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droid
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Comet C/2011 L4 (PANSTARRS)
      #5593168 - 12/28/12 07:13 PM

I just read that Comet C/2011 L4 (PANSTARRS) will be brightest in the March evening sky perhaps 2nd magnitude or better?
With that only being three or so months away, is it visible now in a small telescope or binoculars????


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RobK
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: droid]
      #5593298 - 12/28/12 08:31 PM

Quote:

I just read that Comet C/2011 L4 (PANSTARRS) will be brightest in the March evening sky perhaps 2nd magnitude or better?
With that only being three or so months away, is it visible now in a small telescope or binoculars????




At present it's a southern object only but it has been picked up again after its flirtation with daylight, brightening nicely. I photographed it in twilight on 18 Dec and there have been two observations posted which average out at around mag 9 or a touch brighter. Northern hemisphere observers will have to wait until March 2013 to see it assuming all goes well, but you'll get the best of it! In the south, we will see it until mid-February only, but quite low in the sky. Bright moonlight is currently washing it out visually.

FWIW, here's a link to my image, just a dot!
http://i727.photobucket.com/albums/ww271/Rob_Kau/C2011L418Dec2012smsttext.jpg

Cheers -

Rob


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5593417 - 12/28/12 09:52 PM

Just as Rob indicates, Comet PANSTARRS is currently a Southern Hemisphere object only, soon to be lost in the twilight. Not until very near the time of the comet's perihelion passage (March 10) will it begin to come within range of most of us in mid northern latitudes.

Unfortunately, reliable information concerning the comet's upcoming apparition has been rather sparse of late. Even the February issue of S&T devotes only a relatively brief and general column to PANSTARRS, although it could possibly prove to be a major spectacle in March.

A major point of conjecture concerning the comet's likely performance centers on the fact that the orbit is ever so slightly hyperbolic, implying that this is the first time PANSTARRS has ever passed close to the Sun. Oort Cloud comets like 2011 L4 carry within them a high potential for not living up to expectations with regard to their brightness predictions. Comets Cunningham, Kohoutek, and Austin have been past prime examples of this. Widely heralded as "Great Comets to be", each dramatically failed to live up to anywhere near their early brightness predictions.

Another rather disheartening fact concerning Comet PANSTARRS is that it will be visible only very low in the west in twilight during almost its entire apparition. So, even if it does turn out being very bright, much of its luster could be lost in the fading glow of daylight.

As if to add insult to injury, the March new moon will enter the evening sky just as Comet PANSTARRS becomes visible, the moon's steadily growing brightness thereafter hampering observations of the comet's tail. However, a rather extraordinary imaging opportunity may exist on March 13th. That evening the thin crescent moon is likely to be seen projected onto the outer portion of the comet's ion tail!

BrooksObs

Edited by BrooksObs (12/29/12 08:01 AM)


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Jure Atanackov
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5594080 - 12/29/12 10:23 AM

It's quite amazing to see how the same situation we had with comet C/2006 P1 (McNaught) is repeating with comet C/2011 L4 (PanSTARRS). Observing geometry for comet McNaught during the last three months before perihelion was so poor, that we had almost no useful observations of the comet. It was nearly impossible to make any predictions. The same is now repeating for comet PanSTARRS.

While the comet is still at r~1.7 a.u. and entering the heliocentric distance range where many comets have experienced breaks in their photometric curves, I'm quite optimistic about its current brightness. The last pre-conjunction that I know of and feel comfortable with (experienced observer, good conditions) was by J.J. Gonzalez on August 23 with the comet at m1=9.5 and 6' coma diameter. The last observation of this comet that I know of was by Alexandre Amorim on December 24 at m1=8.1. This was with the Sun at -12° and he only saw 1' of coma, so the comet must actually be much brighter. It's probably pointless to speculate how bright it is, but it just might be doing fine at the moment.

I still vividly remember how C/2002 T7 (LINEAR) fizzled in 2004. It brightened and developed very rapidly in January 2004, heading for a really good show, but then stalled in February and never became brighter than 2nd magnitude. I hope PanSTARRS fares better.
Clear skies!
Jure


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Centaur
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: droid]
      #5596530 - 12/30/12 04:43 PM

I've updated my graphics and data based on Solex orbital elements for Comet C/2011 L4 (PANSTARRS): www.CurtRenz.com/comets

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Centaur]
      #5620188 - 01/13/13 05:05 AM

Quote:

Oort Cloud comets like 2011 L4 carry within them a high potential for not living up to expectations with regard to their brightness predictions.




Jakub Cerny has posted an analysis of the recent brightness measurements and brightening trends on Comets-ML. He suggests that typical of this class of comet (Oort cloud originator) the brightning trend is dropping and that we should now expect a peak brightness 1 mag lower than the prior prodictions. I've attached a link to his analysis graph


http://www.kommet.cz/datas/users/panstarrs-lc-2013_1.jpg

Quote:

Analysis is based on 155 visual observations.




Any coments from the experts here? Is this analysis reasonable?


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5620307 - 01/13/13 08:57 AM

Indeed, Tonk, Jakub's analysis and conclusions are quite valid and not at all unexpected as far as I am concerned. Comet PANSTARRS only just recently reached the approximately 1.5 a.u. solar distance threshold where dynamically "new" comets often exhibit a distinct decrease in their rate of brightening with approach to perihelion.

One of the biggest mistakes in cometary astronomy (particularly among amateurs) in these days of comets being discovered at enormous heliocentric distances is taking the early photometric data and extrapolating the initial brightness parameters all the way to the time of perihelion, particular when small. Behavior at very large solar distances does not imply the same level of activity will prevail when near to the Sun as the outgassing of different volatiles are involved.

The most famous example of this mistake was, of course, made in regard to Comet Kohoutek some forty years ago. As this widely heralded "comet of the century" crossed the orbit of Mars its photometric parameters steadily slowed until they were reduced to those similar to a simple reflecting body. The resulting celestial display, following months of ballyhooing by the press, turned off the general public to astronomers' credibility for years thereafter.

So, the warning goes out once more to be cautious about what is said concerning Comet PANSTARRS' future. Only its brightness behavior from now on until perhaps the very beginnings of March will actually be predictive of how bright it will look to northern hemisphere observers come mid March - all the beautiful plots and graphs compiled throughout 2012 from brightness data likely having little influence concerning what is yet to come.

BrooksObs

Edited by BrooksObs (01/13/13 09:04 AM)


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5620397 - 01/13/13 09:55 AM

Thanks John - nice explanation

Quote:

... to Comet Kohoutek some forty years ago




I missed the hype (UK press didn't seem to get wind of it) but as a 15 year old on my first ever attempt at observing with binnoculars (prompted by a sky chart published in the Times). I found the comet and got hooked. I have only good memories of Kohoutek for that reason.


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5631117 - 01/19/13 07:34 AM

A revised brightness formula prepared by Seiichi Yoshida from recent magnitude measurements of the comet now puts peak brightness at +3

http://www.aerith.net/comet/catalog/2011L4/2011L4.html

Seiichi puts n now at 2.4 with m1 set at 5.5 meaning the comet is less intrinsically bright than originally thought and brightening slower than hoped.

This is a drop from the prior estimate using n = 4.0 and m1 = 4.0.

CN Experts - is this typical with Oort comets? (still learning my way round)


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Centaur
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5631741 - 01/19/13 03:20 PM

Quote:

A revised brightness formula prepared by Seiichi Yoshida from recent magnitude measurements of the comet now puts peak brightness at +3

http://www.aerith.net/comet/catalog/2011L4/2011L4.html

Seiichi puts n now at 2.4 with m1 set at 5.5 meaning the comet is less intrinsically bright than orginally thought and brightening slower than hoped.

This is a drop from the prior estimate using n = 4.0 and m1 = 4.0.

CN Experts - is this typical with Oort comets? (still learning my way round)




Thanks for the info, Tonk. Indeed, estimates for the peak brilliance of a recently discovered distant comet are often reduced (greater magnitude) as it moves closer.

For prediction algorithms, JPL puts the comet total magnitude (M1) at 4.7 and the comet total magnitude slope (K1) at 10. Those are their figures today and have been for some time.

Plugging those figures into the formula puts the current estimated magnitude at +7.1. The greatest brilliance would occur on March 9 at magnitude -0.3.

If your researcher is correct, I suspect JPL will revise its data. At that time I’ll update the related graphics on my website: www.CurtRenz.com/comets


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Jure Atanackov
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Centaur]
      #5634327 - 01/21/13 03:14 AM


Tonk,

the latest analysis of photometric data by Jakub Cerny shows an even worse trend, with the comet reaching only magnitude 3.5 at perihelion.

Clear skies!
Jure


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5634340 - 01/21/13 04:23 AM

Thanks for the update Jure. I haven't read my comets-ml digest this morning

My purchase of a new high quality camera lens was predicated by the prospects of this comet - decision time being mid February. Looks like I'll defer until the autumn for ISON an fall back to my trusty TV85 for this one as I've plenty of experience with imaging mag 4 comets! If ISON doesn't play ball I'll save some money!


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curiosidad
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5634534 - 01/21/13 09:10 AM

Hello,
Such comets are often very unpredictable, and do not know why, they usually get worse!


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: curiosidad]
      #5634588 - 01/21/13 09:44 AM

Quote:

and do not know why




I think the "why" is understood - its down to comet composition and structure. If that could be ascertained when the comet is remote a better prediction would be forthcoming.

However its usually the other way round - how a comet performs amongst other measurements (orbit/spectra etc) gives a clue to what its made of and its structure. I.e. after/during the event and not in advance !


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: curiosidad]
      #5636607 - 01/22/13 10:34 AM

Quote:

Hello,
Such comets are often very unpredictable, and do not know why, they usually get worse!




There a number of competing explanations available, with many of the most recently proposed being highly complex and involved. One of the earlier, simpler, models suggested that dynamically "new" comets, like PANSTARRS, approaching the Sun for the very first time have a thin outer crust, or coating, of highly volatile and easily evaporated material. As the comet first approaches the Sun, these materials sublimate very rapidly and give the impression that the comet is brighter and more active than it really is. However, once gone, the deception ends with the comet's more normal, less active, surface exposed, revealing the intrinsically much fainter and tamer object that it actually is. Honestly there are several variations to this interpretation alone, but the one offered here is probably the most easily understood by the average amateur astronomer.

BrooksObs

Edited by BrooksObs (01/22/13 02:09 PM)


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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5643802 - 01/26/13 04:54 AM

Hi, any news from last days? Is there even any chance for this comet to be visible with tail in 10x50? I mean from northern hemisphere.

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5643934 - 01/26/13 08:20 AM

You will have to wait until March when it is visible in N Hemisphere

Patience!


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5644002 - 01/26/13 09:11 AM

Quote:

Hi, any news from last days? Is there even any chance for this comet to be visible with tail in 10x50? I mean from northern hemisphere.




The most recent observation that I am aware of is this one:

2013 Jan 24.74 UT; m1=7.2; Dia= 5’; DC= 6; 11x70 B [Chris Wyatt, Walcha, NSW,
Australia]
Twilight, tail to WSW, fan shaped WSW to ESE, tail more defined on the NW edge,
5’ in length on the longest side (WSW), ESE edge much shorter. Bright stellar
pseudo nucleus with diffuse and fainter outer coma.

The comet's current magnitude implies a continuation of the reduced rate of brightening exhibited since its recovery several weeks ago. Considering that currently a rudimentary dust tail is evident visually, this suggests that a more prominent example of such a feature will evolve as the comet approaches the Sun.

However, when theoretically near its brightest and best during March the comet will be situated very low in the western sky and backed by rather bright twilight for Northern Hemisphere observers. While this initially did not seem likely to pose a serious problem when the comet's peak magnitude was anticipated to be zero, or brighter, it is increasingly likely that twilight will indeed be a major factor, along with light from the waxing moon, in this likely fainter comet's visibility.

BrooksObs

Edited by BrooksObs (01/26/13 09:14 AM)


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5644491 - 01/26/13 02:22 PM

Quote:

Quote:

Hi, any news from last days? Is there even any chance for this comet to be visible with tail in 10x50? I mean from northern hemisphere.




The most recent observation that I am aware of is this one:

2013 Jan 24.74 UT; m1=7.2; Dia= 5’; DC= 6; 11x70 B [Chris Wyatt, Walcha, NSW,
Australia]
Twilight, tail to WSW, fan shaped WSW to ESE, tail more defined on the NW edge,
5’ in length on the longest side (WSW), ESE edge much shorter. Bright stellar
pseudo nucleus with diffuse and fainter outer coma.

The comet's current magnitude implies a continuation of the reduced rate of brightening exhibited since its recovery several weeks ago. Considering that currently a rudimentary dust tail is evident visually, this suggests that a more prominent example of such a feature will evolve as the comet approaches the Sun.

However, when theoretically near its brightest and best during March the comet will be situated very low in the western sky and backed by rather bright twilight for Northern Hemisphere observers. While this initially did not seem likely to pose a serious problem when the comet's peak magnitude was anticipated to be zero, or brighter, it is increasingly likely that twilight will indeed be a major factor, along with light from the waxing moon, in this likely fainter comet's visibility.

BrooksObs




Today's Spaceweather (26 Jan.) has a recent pic--scroll down the page to see it.

Chris Wyatt's detailed observation report suggests that observers down south are getting a very good look at PANSTARRS. Even without reaching negative magnitudes it could prove to be a very satisfying sight in binoculars or small telescopes come March.

Being low in evening twilight might make for difficult or impossible naked eye observations, but I'll bet it will look good in binoculars.

I know that Comet C/2006 P1 (McNaught) was brighter before perihelion than PANSTARRS will probably ever be, but I needed 10x50 binoculars to get a good view of it just above the horizon when I made this sketch just 2 days before perihelion. Through the binoculars it looked like a magnesium flare. Of course, it then went on to greatness.


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Dave M
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5645883 - 01/27/13 11:33 AM

Quote:


I know that Comet C/2006 P1 (McNaught) was brighter before perihelion than PANSTARRS will probably ever be, but I needed 10x50 binoculars to get a good view of it just above the horizon when I made this sketch just 2 days before perihelion. Through the binoculars it looked like a magnesium flare. Of course, it then went on to greatness.




Be nice if PANSTARRS turned into a Northern Hemisphere (2006 McNaught)


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Dave Mitsky
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5646205 - 01/27/13 02:53 PM

It certainly would.

Dave Mitsky


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5646293 - 01/27/13 03:48 PM

For what it may be worth, I have just performed a linear regression analysis of 24 Southern Hemisphere visual magnitude estimates spanning 2013 January 01 to 26. The results indicate the following brightness formula prevails:

m1 = 5.98 + 5 log(D) + 7.59 log(r) , n = 3.04

I would note that this is in reasonably good agreement with parameters independently determined by Yoshida recently and indicating a much reduced peak brightness in March than had initially be projected.

However, I would add that the scatter in the data is definitely more that I would like to see.

BrooksObs

Edited by BrooksObs (01/27/13 08:06 PM)


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Jure Atanackov
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5646769 - 01/27/13 07:34 PM

I did a similar exercise a couple of days ago with 31 estimates from January 01 to 25 and got: H0=5.7, n=2.8. Both sets of photometric parameters give peak brightness at m1=2.3 (but that's still six weeks away).
Clear skies!
Jure


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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5656235 - 02/01/13 12:06 PM

It's now Feb. the Moon is slowly going away I'm waiting for another obs.

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MikeBOKC
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5656255 - 02/01/13 12:18 PM

There are some good locator charts for PANSTARRS in the new March issue of S&T.

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: MikeBOKC]
      #5656287 - 02/01/13 12:39 PM

Even better ones here

http://cometchasing.skyhound.com/

and here

http://www.shopplaza.nl/astro/comets/comets.htm


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Centaur
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5656354 - 02/01/13 01:19 PM

Quote:

It's now Feb. the Moon is slowly going away I'm waiting for another obs.




Comet C/2011 L4 (PANSTARRS) will reach its maximum southerly declination of 45.6° on 2013 FEB 05 where it is essentially out of sight for observers well north of the tropics. However it will soon be headed northward as the charts and ephemeris on my comets webpage indicate: www.CurtRenz.com/comets

During late February the comet will appear to pass the first magnitude star Fomalhaut. The separation will be only 2.5° on February 26. Unfortunately the Sun will also appear in the vicinity. Below is an equatorial chart I created to illustrate the close approach.



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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Centaur]
      #5657610 - 02/02/13 05:58 AM

Hi, of course I know about March visibility. I had rather in my mind another southern hemisphere observations confirming or denying this very weak 3 magnitude...

Edited by pogrzex (02/02/13 05:58 AM)


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5657707 - 02/02/13 08:46 AM

It would appear that all the most recent incoming photometric data on PanSTARRS only serves to confirm the recent (not unanticipated) reduced rate of brightening. As of yesterday morning the comet was reported as of magnitude 6.5 with a 6' coma and a 0.2-degree, slightly curving, dust tail directed toward the NW.

Once again re-evaluating the growing body of photometric data ths morning and using 26 selected observations spanning Jan. 01 to Feb 02 results in the formula:

m1 = 5.6 + 5 log(D) + 6.6 log r

implying a maximum brightness of no more than +2.0

BrooksObs

Edited by BrooksObs (02/02/13 11:12 AM)


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5658116 - 02/02/13 01:05 PM

Its been a while since a mag +2 comet anyway so I wont sniff at that.

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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5658188 - 02/02/13 01:45 PM

Yep.

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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5659337 - 02/03/13 03:53 AM

Consider that +2 mag is now optimistic scenario.

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Ptarmigan
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5662494 - 02/04/13 09:13 PM

Quote:

Its been a while since a mag +2 comet anyway so I wont sniff at that.




I would not laugh at a magnitude 2 comet either as they are rare as well. Comets are hard to predict.


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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ptarmigan]
      #5664750 - 02/06/13 07:48 AM

Hey, the comet is now making nice gas tail. What does it mean for us?

http://spaceweather.com/submissions/pics/m/Minoru-Yoneto-3238_1360123770_lg.jpg

Edited by pogrzex (02/06/13 10:14 AM)


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Dave M
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ptarmigan]
      #5664850 - 02/06/13 09:21 AM

I`ll take a mag 2 comet any day of the week

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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5665041 - 02/06/13 11:33 AM

Quote:

Hey, the comet is now making nice gas tail. What does it mean for us?

http://spaceweather.com/submissions/pics/m/Minoru-Yoneto-3238_1360123770_lg.jpg




Probably nothing very heartening, I'm afraid. Were PanSTARRS a more active comet one would have anticipated the development of an ion tail significantly early than this. In fact, there apparently still wasn't a detectable one even as late as last week! By way of comparison look at the ion tail on Comet Lemmon which is more typical of a type I tail (and has been present for some time) while currently at 1.2 a.u. from the Sun. Then compared that with PanSTARRS', with that comet at 0.91 a.u. Pretty darn weak, I'd say.

Likewise, the latest observations would seem to indicate that the comet's brightness may be beginning to fall behind even that predicted by the magnitude formula I had posted up-stream, making the prediction of a peak brightness of +2.0 in mid March ever less likely.

BrooksObs

Edited by BrooksObs (02/06/13 12:42 PM)


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azure1961p
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5666105 - 02/06/13 09:57 PM

What magnitude was hale-Bopp or hyakutake?

?

Pete


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: azure1961p]
      #5666184 - 02/06/13 10:44 PM

Quote:

What magnitude was hale-Bopp or hyakutake?

?

Pete





At their peaks, -0.5 and 0.0 respectively.

BrooksObs


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5666193 - 02/06/13 10:48 PM

Ok - thanks.

Still 2+ is impressive in my book. Very-good is entirely acceptable . Frankly anything brighter mag 6 to me is good so this ought to be refreshing.

Pete


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: azure1961p]
      #5666392 - 02/07/13 02:17 AM

Quote:

What magnitude was hale-Bopp or hyakutake?





What significance does it have? They were visible on dark sky easily with naked eye. There is no chance to see +2 mag object with naked eye so low over the horizon + on so bright sky. To me it's no comparison!

Edited by pogrzex (02/07/13 02:17 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5668390 - 02/08/13 06:45 AM

Quote:

There is no chance to see +2 mag object with naked eye so low over the horizon + on so bright sky. To me it's no comparison!




Its called a washout!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5670398 - 02/09/13 09:48 AM

A new analysis of selected visual photometric data spanning Jan 7 to Feb 9 results in the following magnitude formula:

m1 = 5.6 + 5 log(D) + 6.7 log(r) , cc = 0.93

The fit to the data is excellent and it is noted that these parameters are hardly any different from those derived a week ago, suggesting that these terms are becoming quite certain now. They are also rather similar to those derived for Comet Kohoutek back in 1974. Descriptions using binoculars and small telescopes continue to indicate a bright pseudo nucleus within the coma and a short but obvious and rather dramatically curved dust tail, with the ion tail almost absent.

Considering our viewing geometry in mid to late March the above implies an ever more probable peak magnitude of close to +2.5 with the comet displaying a broad, highly curved tail, perhaps of rather low surface brightness which will have reduced visibility particularly when viewed at low elevation against a twilight backdrop.

BrooksObs

Edited by BrooksObs (02/09/13 09:58 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5670516 - 02/09/13 11:08 AM

So, something similar to C/2002 V1 (NEAT) in the second week of Feb 2003...

Mr. Bortle, what do you think about comet Kohoutek's return to a higher n at log(r) < -0.6? Would it be reasonable to expect something similar from PanSTARRS?

http://www.lesia.obspm.fr/perso/nicolas-biver/cometsmagpreperi-2011l4-2012s1.jpg

Clear skies!
Jure

Edited by Jure Atanackov (02/10/13 08:27 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5671957 - 02/10/13 08:28 AM

Jure, while a possibility I would tend to think it is more likely that Comet PanSTARRS' post perihelion behavior will be rather different from Kohoutek's by virtue of PanSTARRS' very high dust production rate. In constrast, Kohoutek showed a strong ion tail, which has been so far very weak in PanSTARRS, and only a modest dust tail (except when very near perihelion) for a comet with such a small perihelion distance. This would imply a marked difference in composition, reflected in the gas vs. dust production ratios of the two objects. PanSTARRS so far seems to be a very dusty comet (particularly "heavy" dust at that).

I would also note that, in my opinion, total magnitude determinations when a comet is further than 2.5 a.u. from the Sun should be regarded as increasingly suspect, particularly those made during the post-T interval, for a number of quite valid reasons.
BrooksObs

Edited by BrooksObs (02/10/13 09:41 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5674257 - 02/11/13 03:32 PM

One thing the low elevation of C/2011 L4 does remind me of is whether or not the ICQ extinction tables/method needs updating.

There are tables provided for altitude to every 0.5 km to account for Rayleigh scattering and the 0.016-mag/air mass extinction for ozone is essentially "baked into the cake".

It's the aerosol extinction, though, that perhaps needs a makeover. There are three tables to account for various aerosol loads ("average", "winter", and "summer"), with the "average" set at 0.120-mag/air-mass and the winter and summer values set at 70% and 130% of that, respectively.

There are multiple issues I've got with this approach. (1) The "winter" extinction table can be used year-round at desert locations and most of Australia, and even that doesn't account for how clean the air can be in these locations. Likewise (2) some locations with humidity and high industrial emissions rarely have clean enough air to justify the "average" extinction table, and (3) the aerosol extinction is assumed to decrease logarithmically with altitude. Normally that's the case, but there could high-altitude haze (e.g. forest fire smoke, volcanic ash) that might be absent from the lowest 10,000-ft altogether.

Aerosol extinction, in other words, simply is what it is for a particular location and time. The only way to really account for it in your estimate is to compare the brightness of stars low along the horizon with those near overhead and to back-calculate the aerosol (and, thus, total) extinction if--IF--an estimate needs to be corrected for atmospheric extinction. It'd be very cumbersome to put it in tabular form, but a simple spreadsheet program with a few inputs would easily suffice.

Obviously an experienced comet observer should go out of his/her way to seek out suitable comparison stars at similar altitudes as the comet to avoid the use of extinction tables altogether, but some comets take away that option from the get-go. And I'd concede that the methodology of the observer can easily introduce as much error and uncertainty as atmospheric extinction to begin with. It's just something that's bothered me for some time, and the low elevation of C/2011 L4 at its brightest just reminds me of it. This isn't meant to be a slight to Dr. Green's very important and well-researched 1992 ICQ article regarding atmospheric extinction; quite the opposite. Maybe it's time to update to procedure a bit by tailoring the equations to specific conditions and locations.

Clear Skies,
Phil


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5674272 - 02/11/13 03:39 PM

For those interested in Dr. Green's article on atmospheric extinction, see:

http://www.icq.eps.harvard.edu/ICQExtinct.html

Clear Skies,
Phil


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5683038 - 02/16/13 09:29 AM

Updating the comet's photometric parameters to include this week's reported observations from select southern hemisphere observers suggests a possible slight up-tick in the figures. However, it must at the same time be appreciated that the comet can now only be observed at extremely low altitude in the morning sky in brightening nautical twilight. Data spanning 2013 Jan 7 to Feb 16 results in the magnitude formula:

m1 = 5.6 + 5 log(D) + 7.1 log(r) cc = 0.97

If carried to perihelion this implies a peak magnitude of 2.1 as seen from the Earth during mid March.

Reports of the comet's appearance as seen with with small instruments and binoculars this week indicates the head to be extremely condensed and the typical double tails (ion and dust) are now both apparent and photographically of almost equal length.

BrooksObs

Edited by BrooksObs (02/16/13 10:22 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5684226 - 02/16/13 08:55 PM

What will be the best time to photograph C/2011 L4? Is the tail likely to grow after perihelion as the comet dims? Even though it will be at its brightest 3/9 I'm just wondering if it will be more photogenic after that as it moves away from the horizon and the tail possibly grows.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: krp]
      #5685013 - 02/17/13 11:33 AM

You will require a unobstruted western horizon. It will set soon in twilight close to the crescent Moon on 12 March 2013. I am expecting dimming of the tail by moonlight and distance above the horizon.

Comet will be in twilght skies. Would like to see it in darker skies, but appreciate any view I can get of this comet in the March skies. Expecting clouds on the horizon to be a hinderence.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: SabiaJD]
      #5685549 - 02/17/13 05:10 PM

KRP - John Sabia is quite correct in his post. The fact is that there is a distinct possibility there won't be a time when the comet's tail will be easily viewable, or can be photographed to real advantage, before it fades.

The head of Comet PanSTARRS will be seen only very low and in the western twilight well into April for mid northern latitude observers, by which time C/2011 L4 will have faded considerably. At the same time odds are that the comet's bluish ion tail could prove difficult to recognize, particularly visually, in the intense twilight. The brighter and more visually apparent dust tail is likely to initially be directed toward the southeast at a low angle and largely subdued by the bright sky. The latter appendage may likely not be seen to project more-or-less upwards in classic comet fashion until fairly late in March, by which time the moon, then in its gibbous phase, could severely hamper any visibility.

So, astro photographers are likely to be faced with a catch as catch can senario, attempting to trade off comet altitude, favorable tail direction, twilight and moonlight interference to gain any impressive images.

BrooksObs

Edited by BrooksObs (02/17/13 05:15 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5685660 - 02/17/13 06:07 PM

Quote:

So, astro photographers are likely to be faced with a catch as catch can senario, attempting to trade off comet altitude, favorable tail direction, twilight and moonlight interference to gain any impressive images.




Indeed - with ten years of comet photography under my belt, this one is proving to be a hard plan!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5685729 - 02/17/13 06:46 PM

Of course, all this is educated speculation at this point.

Have your cameras and pencils ready, folks.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5686515 - 02/18/13 07:44 AM

We can only hope.

Rich (RLTYS)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Rich (RLTYS)]
      #5686866 - 02/18/13 11:57 AM

Far from mere speculation, I'm afraid, Special Ed. In the case of Comet PanSTARRS the facts conspire to give us the least favorable viewing circumstances for any bright comet in decades.

BrooksObs

Edited by BrooksObs (02/18/13 11:58 AM)


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eps0mu0
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5687821 - 02/18/13 09:09 PM

Least favorable viewing circumstances in decades?
At least we'll get a chance.
I seem to remember Kohoutek also had less than optimal viewing circumstances: low in the evening sky right after sunset. I was a fairly young and inexperienced observer, but I was unable to catch it, even though both Venus and Jupiter provided helpful guideposts in the sky.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5687927 - 02/18/13 10:09 PM

Quote:

Far from mere speculation, I'm afraid, Special Ed. In the case of Comet PanSTARRS the facts conspire to give us the least favorable viewing circumstances for any bright comet in decades.

BrooksObs




Hey--not "mere" speculation--I said "educated" speculation. I think you and Tonk and Jure are awesome (and I never use that word).

I'm just hoping that we visual observers and sketchers can see and record something that eludes the AP types (because of exposure issues, etc.).


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5688058 - 02/18/13 11:27 PM

Nice shot of PANSTARRS on spaceweather
http://spaceweather.com/gallery/indiv_upload.php?upload_id=76708


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5688361 - 02/19/13 06:17 AM

WOW! A beautiful image.

Rich (RLTYS)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Rich (RLTYS)]
      #5688368 - 02/19/13 06:31 AM

Indeed.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: eps0mu0]
      #5688501 - 02/19/13 09:05 AM

Quote:

Least favorable viewing circumstances in decades?
At least we'll get a chance.
I seem to remember Kohoutek also had less than optimal viewing circumstances: low in the evening sky right after sunset. I was a fairly young and inexperienced observer, but I was unable to catch it, even though both Venus and Jupiter provided helpful guideposts in the sky.




In point of fact even Comet Kohoutek was far better situated in the sky for observation by northern hemisphere observers than will be PanSTARRS. Kohoutek rose steadily upward from the SW horizon and away from the twilight as January of '74 progressed. PanSTARRS, on the otherhand, will virtually parallel the western horizon from mid March until well into April, never being higher up than 5-10 degrees an hour after sunset in twilight and essentially setting by the time full darkness comes. A nice binocular object in the afterglow of dusk perhaps, but no naked eye spectacle.

Incidentally, looking back over my observing journals, which span 1957 to the present, I cannot find any "bright" comet that was ever so continuously poorly placed for observation from my site following its perihelion as is PanSTARRS!

BrooksObs

Edited by BrooksObs (02/19/13 09:07 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5688582 - 02/19/13 09:54 AM

Quote:

I cannot find any "bright" comet that was ever so continuously poorly placed for observation from my site following its perihelion as is PanSTARRS!




Indeed - should be called PantsARRS


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AlaskaIsCold
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5691917 - 02/20/13 10:52 PM

I really hope that it puts on a reasonably good show.
But even if it does. Odds are I wont be able to image it.
I mean really how often do you hear "It was a star filled crystal clear march night in anchorage alaska." hahaha. Still though *fingers crossed*


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5693190 - 02/21/13 05:32 PM Attachment (46 downloads)

Quote:

Quote:

Least favorable viewing circumstances in decades?
At least we'll get a chance.
I seem to remember Kohoutek also had less than optimal viewing circumstances: low in the evening sky right after sunset. I was a fairly young and inexperienced observer, but I was unable to catch it, even though both Venus and Jupiter provided helpful guideposts in the sky.




In point of fact even Comet Kohoutek was far better situated in the sky for observation by northern hemisphere observers than will be PanSTARRS. Kohoutek rose steadily upward from the SW horizon and away from the twilight as January of '74 progressed. PanSTARRS, on the otherhand, will virtually parallel the western horizon from mid March until well into April, never being higher up than 5-10 degrees an hour after sunset in twilight and essentially setting by the time full darkness comes. A nice binocular object in the afterglow of dusk perhaps, but no naked eye spectacle.

Incidentally, looking back over my observing journals, which span 1957 to the present, I cannot find any "bright" comet that was ever so continuously poorly placed for observation from my site following its perihelion as is PanSTARRS!

BrooksObs




As stated above, Kohoutek was a difficult comet to find in early twilight the first week of Jan 1974. By the second week of January 1974, it was higher in altitude and easily seen against a darker background sky before setting.

This image of C/1973 E1 Kohoutek take on January 4,1974 EST. KAF 500 Slide Film, 400mm telephoto lens mounted on a equatorial mount. Taken by my friend Ken Mason

Stars on right are Alpha and Beta Capricorni

Edited by SabiaJD (02/21/13 05:35 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: SabiaJD]
      #5693303 - 02/21/13 06:33 PM

Wow - brings back memories. Kohoutek was my first astronomical observation and my entry into the astronomy hobby

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5696198 - 02/23/13 09:04 AM

Updating my previous posts concerning the evolution of C/2011 L4, it is significant to note that no sightings of the comet seem to have been reported by southern hemisphere observers over the past 3 days as the comet moves ever deeper into the twilight. At last report PanSTARRS was 4th magnitude with a 1 degree tail, situated very low in the afterglow of dusk about 29 degrees almost due south of the Sun and visible only briefly in nautical twilight. Although continuing to brighten steadily, it seems ever more likely that the comet may become temporarily lost in twilight as its elongation from the Sun dwindles to just 15 degrees between now and March 10th. Just when it might be visually recoverable by northern hemisphere observers remains open to question and highly dependent on just how bright the comet becomes.

As of today selected photometric observations covering the past 6 weeks indicates a very steady but slow rise in the comet's brightness and development. An analysis of these data indicate that they can be very well represented by the formula:

m1 = 5.6 + 5 log(D) + 6.9 log(r)

as can be seen from the graph presented below.



These parameters, only very slightly differing from those presented earlier, but now even more certain, suggest a peak brightness of about +2.2 on or about March 10th, with a slow progressive fading thereafter taking the comet to about magnitude +5.0 by month's end.

These parameters also imply a resemblance to Comet Mrkos, 1957 P1, both in regard to observational geometry and brightness. If this is true, then PanSTARRS could put on a fairly respectable showing during late March and early April although heavily impacted by the inconvenient timing of the March full moon.

If PanSTARRS attains 2nd magnitude it should likewise exhibit a fairly broad, strongly curving, dust tail between 5 and 15 degrees in extent. How much of this will be suppressed by the bright twilight in mid March is, of course, open to question. However, those with the lowest western horizons and clearest, darkest, skies are likely to be favored since this will allow following the comet as late as possible in the dying twilight glow.

BrooksObs

Edited by BrooksObs (02/23/13 11:46 AM)


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Rich (RLTYS)Moderator
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5699332 - 02/25/13 06:35 AM

Quote:

Wow - brings back memories. Kohoutek was my first astronomical observation and my entry into the astronomy hobby




The latest issue of S&T has a good article on Kohoutek.

Rich (RLTYS)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5700794 - 02/25/13 11:29 PM

Quote:

...it is significant to note that no sightings of the comet seem to have been reported by southern hemisphere observers over the past 3 days as the comet moves ever deeper into the twilight.




Not quite right, there has been a steady stream of sightings right through. You probably need to cast your net a bit wider, into southern astronomy forums, groups, blogs etc. The comet has been both a morning and evening object recently - in evening skies, I first imaged it on 17 Feb and since then there have been regular evening sightings, images and observations. Observations are the problem due to the difficulties with bright skies but some experienced observers are now reporting it in the mag 3s. I last saw it visually on the morning of 16 Feb (15 Feb UT) in fairly bright sky after it had cleared an annoying cloud band! It was beautiful, a 'classic' comet - a small, very bright inner coma (false nucleus) surrounded by a small coma swept back into a large broad fan tail, with a bright edge each side. And this was through a very modest telescope.

Regardless of its performance at perihelion and observing it in bright skies, I think you northerners have a real treat in store for you! I'm still hoping to get another look at it, but first I have to get rid of bushfire smoke and cloud which has plagued me since the 17th!

Cheers -

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5700824 - 02/26/13 12:01 AM Attachment (59 downloads)

FWIW here's my PANSTARRS images from 15 & 17 Feb. All were taken in bright sky through thin cloud. There are a lot better than these around! The garish one from 17th was particularly difficult, with the comet at less than 3-deg altitude, twilight background glow and a bright Moon illuminating a band of haze and smoke.

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5701081 - 02/26/13 07:22 AM

Rob, nice images of Comet Panstarrs, thanks for the views. At this point I'm quite jealous.

Rich (RLTYS)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Rich (RLTYS)]
      #5701107 - 02/26/13 07:41 AM

Thanks Rich, I suspect I'll be the one who is jealous shortly!

I should add in regard to the image on 17 Feb that it is presented at a much wider scale than the other two - aside from the poor sky condition, there was a another hiccup in that my polar alignment slipped without me noticing and hence there was bad star trailing.

Cheers -

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5701320 - 02/26/13 10:09 AM

Rob,

Thanks for the report and images--they look good.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5701450 - 02/26/13 11:28 AM

Quote:

Quote:

...it is significant to note that no sightings of the comet seem to have been reported by southern hemisphere observers over the past 3 days as the comet moves ever deeper into the twilight.




Not quite right, there has been a steady stream of sightings right through. You probably need to cast your net a bit wider, into southern astronomy forums, groups, blogs etc. Rob




To be honest, Rob, I peruse mostly those sites posting reliable observations from experienced comet observers, north and south, because of the often mistaken and error-prone posts one sees on so many of the "popular" astronomy websites.

As things stood, for the first time in weeks a 5-day gap (Feb 20-25) appeared in the posted data on the sites I cover. Only last evening did a new, rough, observation from the evening of the 24th get posted by John Drummon of Gisborne, NZ. John noted the comet to be "about" magnitude 3.0 with a short tail, situated very low in the sky deep in the evening twilight. This approximate magnitude is in rather good agreement with the parameters I had posted earlier.

Unfortunately, the comet's position in bright twilight and with a lack of much in the way of really suitable comparison stars is likely going to severely hamper accurate observation of PanSTARRS for some time to come, as the same difficulties will prevail when the comet first becomes visible to northern observers.

Incidentally, nice photos on your part!

BrooksObs

Edited by BrooksObs (02/26/13 11:40 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5702162 - 02/26/13 05:50 PM

Nice shots Rob. How much did you crop that last one?

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: krp]
      #5702188 - 02/26/13 06:08 PM

This Japanese folk Minoru Yoneto in New Zealands has been following the comet photographically with a decent setup.

http://homepages.ihug.co.nz/~mkyoneto/camel.htm

His latest photo of the comet taken on the 22nd (UT) shows a dust tail of 2 degrees. The ion tail was still rather weak though.

Anyways this is a great resource for up-to-date photographic references on the comet's development. Looking at the lovely dust tail I'm sure we northerners have something great in store awaiting.

Jack

Edited by jiahao1986 (02/26/13 06:10 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5702428 - 02/26/13 08:42 PM

Nice image of PANSTARRS. Looks rather bright.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ptarmigan]
      #5704916 - 02/28/13 08:57 AM

For those northerners awaiting their first glimpse of Comet PanSTARRS the latest sightings reported by southern observers earlier today continue to show the comet to be following the magnitude formula I posted here last weekend very closely. The comet is now about 2nd magnitude and in addition displays three distinct short tails on briefly exposed images. There is a moderately obvious straight ion (gas) tail, a classic gently curving normal dust tail, and a much shorter and fainter feature that in years gone by was often classified as a type III "heavy dust" tail. All three taken together present a very broad fan of bright material issuing from the comet's head and spanning an arc roughly 75 degrees in breadth. What sort of tail lengths may be apparent visually in the very bright twilight of mid March for northerners remains to be seen, but with the comet's head shining at +2.0, or possibly even a little brighter, at least a few degrees can be confidently anticipated and the comet should present a fine sight for those with binoculars.

BrooksObs

Edited by BrooksObs (02/28/13 09:14 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5705204 - 02/28/13 12:03 PM

Quote:

For those northerners awaiting their first glimpse of Comet PanSTARRS the latest sightings reported by southern observers earlier today continue to show the comet to be following the magnitude formula I posted here last weekend very closely. The comet is now about 2nd magnitude and in addition displays three distinct short tails on briefly exposed images. There is a moderately obvious straight ion (gas) tail, a classic gently curving normal dust tail, and a much shorter and fainter feature that in years gone by was often classified as a type III "heavy dust" tail. All three taken together present a very broad fan of bright material issuing from the comet's head and spanning an arc roughly 75 degrees in breadth. What sort of tail lengths may be apparent visually in the very bright twilight of mid March for northerners remains to be seen, but with the comet's head shining at +2.0, or possibly even a little brighter, at least a few degrees can be confidently anticipated and the comet should present a fine sight for those with binoculars.

BrooksObs




John,

I've got a set of 15x70's that are just waiting for a chance to collect some photons from this comet, so I'm definitely looking at the period between March 20 - March 25 to allow it get a little higher.

Based on your experience, does C/2011 L4 stand a decent chance of having a post-perihelion "bump" in brightness/dust production, or at least a brief period of a few days to a week or more after perihelion where the output remains the same before decreasing?

Clear Skies,
Phil


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5705247 - 02/28/13 12:24 PM

So this comet might be a dud,after all the hype I've read about it,I hope this isn't the case for the comet coming this fall. I've been waiting for a naked eye comet with a tail for a looooong time(And I hope I get to see PANSTARRS with binoculars later in March).

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: OldDeadOne]
      #5705376 - 02/28/13 01:43 PM

The latest update from S&T is here:

http://www.skyandtelescope.com/observing/highlights/Comet-PanSTARRS-Updates-1...

An observation on 2/28 has the comet at mag 2.6! IF, and that is a big IF, this is correct PanSTARRS is running about 1/2 mag behind the original light curve.

We might get a very good show!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Darren Bly]
      #5705417 - 02/28/13 02:04 PM

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5705473 - 02/28/13 02:45 PM

Quote:

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky




That's my understanding. Remember Comet IRAS–Araki–Alcock? IRAS stood for Infrared Astronomical Satellite so this is really nothing new.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5705514 - 02/28/13 03:02 PM

Hi, Phil. I expect that you will get a fine view indeed with those 15x70 binoculars. Actually they will be the instrument of choice for me as well for doing much of my observation of PanSTARRS.

Concerning the possibility of PanSTARRS exhibiting a perihelion asymmetry (a post-T bump) in its lightcurve, while for comets nothing can be absolutely ruled out for any given one, I would speculate that the odds for C/2011 L4 deviating much from the photometric parameters reflected by the Jan and Feb observations are vanishingly small. Perihelion asymmetry is generally not an aspect commonly displayed by dynamically "new" comets. Likewise, PanSTARRS is already proving to be extraordinarily dusty for a "new" comet, so I would not anticipate any further slowing down and holding its brightness longer during the post-T interval.

What concerns me most at present is how northern observers will interpret the comet's visual impact. The geometry between PanSTARRS and Earth are such that its dust tail will be present almost exactly side on to us, resulting in a low overall surface brightness. At the same time PanSTARRS will be seen against a portion of the sky with very few really bright stars to compare it with, compounded by its being set against a bright twilight sky (at least early on). I feel that the result will be a very wide scatter in observers' opinions as to just how bright and impressive it is. Some observers will sure consider it a very nice and bright object, while other opinions will surely range on down all the way to bitter disappointment. Certainly, no one should be in anticipation of another Comet McNaught at this point. In fact, as I had warned earlier, we will see Comet PanSTARRS under the most unfavorable viewing circumstance for any really bright comet in nearly the past half century!

BrooksObs

Edited by BrooksObs (02/28/13 03:05 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5705551 - 02/28/13 03:24 PM

Quote:

I've been unable to find a source that discusses this matter.




Try the comets-ml yahoo group - its a recuring and lengthy topic with references to the official rules etc

Short answer is yes - otherwise a comet ends up with a huge series of names.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5705567 - 02/28/13 03:29 PM

Quote:

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky




Dave, I covered the answer to this question in fair detail recently in the "What scope R U gonna use for Upcoming comets!!" thread. Rather than repeat it again here, might I refer readers to that post.

BrooksObs

Edited by BrooksObs (02/28/13 03:30 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5706284 - 02/28/13 10:01 PM

Quote:

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky




This link might help (or not!):
http://www.icq.eps.harvard.edu/cometnames.html

"Today there are numerous professional CCD survey programs that scan the sky most clear nights of each month looking for near-earth objects (NEOs), which are usually minor planets (or more rarely, comets) that pass -- or can pass -- within about 0.1 AU of the earth. Convention is now that most comets found by such surveys, which each employ numerous people, are labelled/named usually (but not always) for the survey program name; thus, we have some 117 comets labelled "LINEAR" as of Sept. 2003, 35 comets labelled for "NEAT", nine comets labelled for "LONEOS", seven comets labelled "Spacewatch", four comets labelled "Catalina", and three comets labelled "Tsuchinshan", Sometimes two-member teams will get both names on a comet, but two names is a firm limit for such teams; occasionally a single astronomer from a large-survey program will be the observer, discoverer, and communicator of a new comet discovery, and such individual names are in such cases sometimes allowed to go with the comet rather than the team name."

Cheers -

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5706578 - 03/01/13 03:54 AM

Quote:

occasionally a single astronomer from a large-survey program will be the observer, discoverer, and communicator of a new comet discovery, and such individual names are in such cases sometimes allowed to go with the comet rather than the team name




E.g. McNaught or Garradd (etc) otherwise in this case they would be labelled "Siding Springs" - this does happen if Rob or Gordon submit the object as an asteroid and it later turns out from someones elses observation to be a comet (e.g. C/2013 A1)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5706582 - 03/01/13 04:01 AM

Quote:

Quote:

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky




Dave, I covered the answer to this question in fair detail recently in the "What scope R U gonna use for Upcoming comets!!" thread. Rather than repeat it again here, might I refer readers to that post.

BrooksObs




Thanks, John. I found a page that discussed the matter briefly after I posted my query here.

Dave Mitsky


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5706585 - 03/01/13 04:05 AM

Quote:

Quote:

Is the reason that comets discovered by automated survey systems such as Pan-STARRS, LINEAR, and NEAT are named after the surveys simply because there are, I assume, a number of individuals involved in conducting such surveys? I've been unable to find a source that discusses this matter.

Dave Mitsky




This link might help (or not!):
http://www.icq.eps.harvard.edu/cometnames.html

"Today there are numerous professional CCD survey programs that scan the sky most clear nights of each month looking for near-earth objects (NEOs), which are usually minor planets (or more rarely, comets) that pass -- or can pass -- within about 0.1 AU of the earth. Convention is now that most comets found by such surveys, which each employ numerous people, are labelled/named usually (but not always) for the survey program name; thus, we have some 117 comets labelled "LINEAR" as of Sept. 2003, 35 comets labelled for "NEAT", nine comets labelled for "LONEOS", seven comets labelled "Spacewatch", four comets labelled "Catalina", and three comets labelled "Tsuchinshan", Sometimes two-member teams will get both names on a comet, but two names is a firm limit for such teams; occasionally a single astronomer from a large-survey program will be the observer, discoverer, and communicator of a new comet discovery, and such individual names are in such cases sometimes allowed to go with the comet rather than the team name."

Cheers -

Rob




Thanks, Rob. The following link within the article that you linked spelled out the convention clearly.

http://www.ss.astro.umd.edu/IAU/csbn/cnames.shtml

Dave Mitsky


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5707021 - 03/01/13 11:25 AM

Looks like there is a chance to get a bit brighter than 2 mag. Still biggest question is just how will it look in my 10x50's. 3 degree tail (or more) is in my opinion minimum to be called "exctiting view" any chances for that?

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5709030 - 03/02/13 03:47 PM

Latest update concerning Comet PanSTARRS' brightness. A couple of further brightness observations from recent days indicates that the comet continues to brighten nicely. A new reduction of selected available magnitude estimates is illustrated in the graph below.



The resulting magnitude formula reads as follows:

m1 = 5.6 + 5 log(D) + 7.5 log(r)

The comet's currently projected maximum brightness based on this formula is between +1.5 and +2.0 for a couple of days around March 10th, with PanSTARRS remaining a bit brighter thereafter than earlier envisioned.

BrooksObs


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5709067 - 03/02/13 04:10 PM

Things are looking up, so to speak, for Comet PanSTARRS. I've seen a couple of reports of the comet having reached naked-eye visibility. There's a photo taken over light-polluted Melbourne on March 2nd posted at http://spaceweather.com/gallery/indiv_upload.php?upload_id=77081

Dave Mitsky


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Jure Atanackov
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5709220 - 03/02/13 05:48 PM

Also, first striae are appearing in the dust tail:

http://spaceweather.com/gallery/indiv_upload.php?upload_id=77090

CS!Jure


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5709249 - 03/02/13 06:02 PM

where in the sky will it be available for us to look for it and when? I will be using my son's binoculars

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5709377 - 03/02/13 07:01 PM Attachment (20 downloads)

Hi all. The striae have been around for a few days - I imaged the comet on 01 March and if you check this image you'll see one stria extending faintly to the top of the frame, a length of about 3 degrees:
http://i727.photobucket.com/albums/ww271/Rob_Kau/C2012L401Mar2013text.jpg

We went to a mountaintop location to view the comet. That gave a flat horizon, and skies were very clear. The comet was a wonderful sight, quite bright naked-eye with a 1-degree tail showing strongly. The head looked like a moderately bright star, not as bright as nearby Fomalhaut. It became easier to see as the sky darkened but faded again as the rapidly increasing airmass near the horizon did its stuff! So there was a sweet-spot of about 15-20 mins for naked-eye viewing. The naked-eye view was not unlike this (darken the sky a little in your mind's eye!):
http://i727.photobucket.com/albums/ww271/Rob_Kau/IMG_0103sm.jpg

In binoculars it was beautiful, and clearly visible even fairly early in twilight in a light sky.

Cheers -

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5709413 - 03/02/13 07:30 PM

By the way, I should add that none of the photographs around do justice to the visual view. They all burn out the head - I tried even short exposures of a second or two and none revealed the beautiful, bright little inner coma (false nucleus). What a treat you've got in store for you!!

Rob

Edited by RobK (03/02/13 07:30 PM)


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dan777
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: OldDeadOne]
      #5709473 - 03/02/13 07:58 PM

Quote:

where in the sky will it be available for us to look for it and when? I will be using my son's binoculars



http://www.skyandtelescope.com/skytel/beyondthepage/185665152.html


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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: dan777]
      #5709895 - 03/03/13 03:11 AM

So in the first week after perihelion light pollution will not have any significant disturbing effect?

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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5710061 - 03/03/13 07:51 AM

Quote:

Hi all. The striae have been around for a few days - I imaged the comet on 01 March and if you check this image you'll see one stria extending faintly to the top of the frame, a length of about 3 degrees:
Rob




In fact, the features that folks seem to be calling "striae" (at least based on the photos I've examined) are really the comet's different tails. The long narrow and seemingly independent appendage at the right side of the tail complex is the comet's Ion, or gas, tail. The dense central column of brighter material is the classic dust tail, which if the sky was darker would be seen to curve progressively to the left as it advances. And the left-most shorter fan with the sharp trailing edge of material represents a spray of much heavier dust, years ago referred to in comet circles as a Type III tail.

This latter feature isn't too often seen, but our current almost perfectly side-on view of PanSTARRS is providing us with the best structural view of a large comet's tail in decades. More typically our view of bright comet tails is decidedly foreshortened.

BrooksObs


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5710449 - 03/03/13 11:26 AM

The three different types of tails are easily discernible (we had an opportunity to see a nice Type III tail with C/2001 Q4 (NEAT) in 2004). But there are features in the 'classic' dust tail, that appear to be striae:

http://spaceweather.com/gallery/full_image.php?image_name=Minoru-Yoneto-3303_...

CS!Jure

Edited by Jure Atanackov (03/03/13 11:29 AM)


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jure Atanackov]
      #5710659 - 03/03/13 01:27 PM

Quote:

The three different types of tails are easily discernible (we had an opportunity to see a nice Type III tail with C/2001 Q4 (NEAT) in 2004). But there are features in the 'classic' dust tail, that appear to be striae:

http://spaceweather.com/gallery/full_image.php?image_name=Minoru-Yoneto-3303_...

CS!Jure




Quite honestly, Jure, I see no evidence of striae in the tail in the image accompanying your post. There are some tail streamers apparent near the leading edge of the main tail, but that is it.

Tail striae originate as very brief dust outbursts/ejections from the nucleus and generally only become noticeable once they have moved fairly well out into the tail. Their long dimension will also be aligned at an angle to the axis of the main tail itself, making them look like narrow stripes across the tail (as with Comet McNaught). I really cannot say that I've seen evidence of those sorts of features in any images of PanSTARRS I've examined so far.

BrooksObs


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5710693 - 03/03/13 01:53 PM

There's an image of Comet PanSTARRS posted at http://spaceweather.com/gallery/indiv_upload.php?upload_id=77134 that may be the first one captured from the northern hemisphere.

Dave Mitsky


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5710799 - 03/03/13 02:55 PM

Quote:

may be the first one captured from the northern hemisphere




Ah the IR filter trick


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Ptarmigan
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5711190 - 03/03/13 06:35 PM

Comet PANSTARRS is at magnitude 2.3.

http://www.skyandtelescope.com/observing/highlights/185665152.html

Edited by Ptarmigan (03/03/13 06:38 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ptarmigan]
      #5711870 - 03/04/13 01:58 AM

The daytime skies here in Karachi have been a beautiful crisp blue and the night time skies wonderfully transparent since February's last week. Eagerly looking ahead to the evening sightings of the comet.

Haven't been able to edit the ssystim.ini file within the <Documents&settings\<username>\application data\stellarium\data> folder because the parent folder is locked and I cannot open it, so not exactly sure when PanSTARRS would first appear above the horizon at dusk from my city (24.9 N). Anyway I hope the excellent skies all the way to the horizon continue to be around.

I have a cross-country flight scheduled for the 10th around dusk Trying to secure a left window side seat on that 747, because it would be facing west

I've already seen the Milky Way, Omega Centauri and a meteor from an airplane window: http://dawn.com/2013/02/16/is-it-a-plane-is-it-a-ufo-no-it-is-the-iss/ Comet PanSTARRS would be a very nice addition to the list. Let's see how it goes.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5712275 - 03/04/13 10:52 AM

Beautiful shot Rob..
I cant wait to see it here up North ..


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5712366 - 03/04/13 11:53 AM

I really hope the comet keeps getting brighter (or at the very least, stays at around mag two-ish) for the next couple of weeks

Edited by tezster (03/04/13 11:54 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: tezster]
      #5712728 - 03/04/13 03:21 PM

I would be happy with a mag 2-ish comet. My girls would get to see their first naked eye comet.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5712860 - 03/04/13 04:34 PM

Quote:

Haven't been able to edit the ssystim.ini file within the <Documents&settings\<username>\application data\stellarium\data> folder because the parent folder is locked and I cannot open it, so not exactly sure when PanSTARRS would first appear above the horizon at dusk from my city (24.9 N).




You no longer have to add orbital elements manually. You can go to Configuration Window, Plugins, Solar System Editor, Solar System, Add new solar system objects.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: dan777]
      #5713259 - 03/04/13 08:11 PM Attachment (31 downloads)

Thanks a bunch Dan! It worked. Here are the elements I'm using:

[PANSTARRS]
name = C/2012 L1 (PANSTARRS)
parent = Sun
radius = 10
oblateness = 0.0
halo = true
color = 1.0,1.0,1.0
tex_halo = star16x16.png
tex_map = nomap.png
coord_func = comet_orbit
orbit_TimeAtPericenter = 2456329.3937
orbit_PericenterDistance = .337628
orbit_Eccentricity = 1.0
orbit_ArgOfPericenter = 331.2931
orbit_AscendingNode = 67.5247
orbit_Inclination = 59.95487
lighting = false
albedo = 1
orbit_visualization_period = 365.25

But it seems that Stellarium is plotting the comet one month ahead of where it should be. The 5th Feb position is perhaps where it should be on 6th or 7th March, no?


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5713344 - 03/04/13 08:45 PM

Newton would weep at that path!

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dan777
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5713688 - 03/05/13 12:24 AM

Quote:

But it seems that Stellarium is plotting the comet one month ahead of where it should be.



I think you're getting C/2011 L4 PanStarrs mixed up with C/2012 L1 Linear


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AlaskaIsCold
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5713796 - 03/05/13 02:45 AM

I am hoping that I can image it with my Wide Field Newtonian.
610mm 6" should be zoomed in enough to see something (Hopefully not -too- close up) If I can see something -really- good then I get to break out the 4x5 with the 90mm equiv. lens and hope for the best.


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5714172 - 03/05/13 10:48 AM

Quote:

Thanks a bunch Dan! It worked. Here are the elements I'm using:

[PANSTARRS]
name = C/2012 L1 (PANSTARRS)
parent = Sun
radius = 10
oblateness = 0.0
halo = true
color = 1.0,1.0,1.0
tex_halo = star16x16.png
tex_map = nomap.png
coord_func = comet_orbit
orbit_TimeAtPericenter = 2456329.3937
orbit_PericenterDistance = .337628
orbit_Eccentricity = 1.0
orbit_ArgOfPericenter = 331.2931
orbit_AscendingNode = 67.5247
orbit_Inclination = 59.95487
lighting = false
albedo = 1
orbit_visualization_period = 365.25

But it seems that Stellarium is plotting the comet one month ahead of where it should be. The 5th Feb position is perhaps where it should be on 6th or 7th March, no?




Little surprise, Yaar, that Stellarium is giving falses positions in that every one of the orbital elements you've listed is inaccurate for C/2011 L4. In fact, the orbital inclination value is tens of degrees off and even the name you indicate is incorrect! The bright Comet PanSTARRS C/2011 L4, not L1.

I don't know where you might have obtained these elements, but in the future I'd certainly not rely on that site again for elements!

BrookObs


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Yaar
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5714263 - 03/05/13 11:38 AM

Thank you Dan and BrooksObs. I copied the (mixed-up) elements from this forum and also from the SourceForge.net forums. I'm glad you guys caught the embarrassing error.

Now I opened the configuration window and under the "Solar System tab" of the "Solar System objects" window, clicked the "Import orbital elements in MPC format" button at the bottom of the tab. An "import data" window opens. Under the "Lists" tab of the "Import data" window, I selected the "Type" as "Comets" and the "Source" as "Download a list of objects from the internet"; under "Or select from the list" I chose "Select bookmark" and then "MPC's list of observable comets," and then clicked the button "Get orbital elements."
A list of objects found was loaded. Scrolled down and checked PanSTARRS (the correct one!) and ISON.

Thanks for the help guys PanSTARRS is already above our horizon at dusk but it still very low.


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5714369 - 03/05/13 12:35 PM

I'd suggest that you get orbital elements from MPC direct and not secondhand mangled data

The index for all comets is here http://minorplanetcenter.org/iau/Ephemerides/Comets/index.html

and from the list - C/2011 L4 (Pan-STARRS) - http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=CK11L040

and files that hold the full MPC comet list can be uploaded from here for various software packages - http://www.minorplanetcenter.net/iau/Ephemerides/Comets/SoftwareComets.html


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5714394 - 03/05/13 12:46 PM

Beautiful image Rob - best I've seen - I love the dark sky

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5714588 - 03/05/13 02:29 PM

According to the picture taker, it was taken at NOON in France. This would make it about 6am EST the same day. He said is was "only visible during the day".

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: cpsTN]
      #5714603 - 03/05/13 02:35 PM

Quote:

He said is was "only visible during the day".




Yeah figures as in N hemi on that date comet rose after sun and set before sun


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5714641 - 03/05/13 02:57 PM

A corrected one needs to be made for stellarium...or what do I need to replace to make it correct?

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: tezster]
      #5715115 - 03/05/13 06:58 PM

Quote:

I really hope the comet keeps getting brighter (or at the very least, stays at around mag two-ish) for the next couple of weeks




Sky and Telescope now reporting that it looks likely to be brighter than mag 2 on Mar. 10th. Scouting out a good viewing location now! Just hoping the weather cooperates at least one or two days from the 10th onward, I'd like to get one night in of observing/sketching it and another night of imaging it.


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RolandosCY
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: drbyyz]
      #5715743 - 03/06/13 01:46 AM

Has anyone spotted it in the evening twilight yet from northern latitudes? No luck yet at 35N...

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norton67
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: drbyyz]
      #5715899 - 03/06/13 07:16 AM

I hope we get to see this comet here in Michigan. It has been cloudy almost everyday and night for 6 weeks plus.

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Yaar
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RolandosCY]
      #5715930 - 03/06/13 08:11 AM

Sighting report posted on the S&T PanSTARRS page by Al Sunni:

Quote:

I may be the first to spot Comet PanStarrs in northern hemisphere Tuesday 5th from latidude 15+ KHARTOUM, SUDAN. It was about 3 degrees above local horizon at about 7:25 PM Local Time after sunset but it was faint to see details because of poor seeing it was 17 southwest of the sun and I suggest its mag to be 1+.




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Yaar
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5715933 - 03/06/13 08:14 AM

Another later sighting report by Rich Jones posted on the same page:

Quote:

Tampa Bay Area Fla, USA, 27d55m Lat N; 82d42m Long W; Tues evening 05 March 2013 at 06:45 EST (11:45 UTC). Sky was crystal clear, local sunset at 06:32 EST. Observed Comet PanSTARRS in western sky with naked eye. Surprisingly bright. Approx 10d above twilight horizon. Great sight with 10x50 binoculars. Comet color appeared golden in the evening twilight conditions. Tail was well developed & Vee-shaped with bottom of Vee pointed toward sun. No problem seeing with naked eye even in bright twilight. Estimate 1st magnitude or brighter. Sky & tel location info a great assist, Thanks!!




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dan777
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: OldDeadOne]
      #5716010 - 03/06/13 09:15 AM

Quote:

A corrected one needs to be made for stellarium...or what do I need to replace to make it correct?




Bert, I'm not sure I understand your question. I've had PanStarrs in my Stellarium for quite some time.


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RobertED
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5716012 - 03/06/13 09:16 AM

Yukky weather here in RI since Christmas....hoping for next week!!!!

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magic612
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobertED]
      #5716086 - 03/06/13 10:01 AM

I've not seen anything yes, but like norton67 we've been almost entirely cloudy for the last 5 weeks or so here near Chicago. I had one clear night a few days ago, but it wasn't really clear in the evening hours. Skies are SUPPOSED to be only "partly cloudy" for the next several days, but whether that means clear to the west at sunset is another matter altogether.

I made some daily "here's where the comet is at exactly 30 minutes past sunset" charts to help both photographers (and me!) find the comet's location every day. So far I just have March 10 through 17 up, but I'll be posting graphics for it's location through early April, as the comet, though fading in magnitude, will be near M31 once it gains a bit of elevation and moves more northward.

http://eyesonthesky.com/Blog/CometPANSTARRS.aspx

(I also made that page to contain lots of caveats about seeing it in sunlight/twilight, as many press reports seem to suggest that a 1st magnitude object is "spectacular" or "dazzling" in twilight. Having viewed Mercury many times at dusk, my caution is to simply lower expectations as I don't believe this comet will reach Hale-Bopp-type visibility. So take my caution written on that page with a grain of salt if you're used to comet observing like this - it's meant to manage what people can expect to see. And I'd much rather be wrong about it appearing dim or hard-to-see than suggesting to the general public that it looks really, really bright.)


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Phillip Creed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: magic612]
      #5716329 - 03/06/13 12:50 PM

Here's some awesome footage of C/2011 L4 with low-light cameras, both wide-angle and through a 10" reflector, from the Northern Tablelands of Australia:

http://www.youtube.com/watch?v=7xvILkuznQ0

Clear Skies,
Phil


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MDB
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5716372 - 03/06/13 01:18 PM


Thank you Dave!

Mike


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dyslexic nam
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: MDB]
      #5716510 - 03/06/13 02:15 PM

I am ridiculously excited about seeing this. I will be downtown Toronto on the 14, so no chance of seeing it then - need to hope for a couple of clear nights on the 12th or 13th...

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RolandosCY]
      #5716624 - 03/06/13 03:10 PM

Quote:

Has anyone spotted it in the evening twilight yet from northern latitudes? No luck yet at 35N...




CN member PrestonE reported seeing it at 6:50 p.m. on March 4 from an altitude of 6,000 feeet in Mexico (21 degrees north).

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/genobs/Number...

Dave Mitsky


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Mike B.
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RolandosCY]
      #5716938 - 03/06/13 05:49 PM

I tried last night (3/5/13) with a pair of Celestron 15x70 binoculars, but I was unable to spot it. (I'm at 30 degrees N. Latitude.) There was too much murk and clouds on the horizon. I will try again tonight with the bino's, since it is much clearer today. Plus, I have an old CG3 mount w/clockdrive and my camera mounted on it that I plan on using to take some images. I might get lucky.

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REC
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Mike B.]
      #5717059 - 03/06/13 06:54 PM

Just saw it tonight at 6:30 pm in NC. Very bright and naked eye for sure! Binoculras showed a streak, so no star. Only about 5-10* over the horizon and visible for about 15 min. before it sank. Looks really promising:)

Bob


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Mike B.]
      #5717165 - 03/06/13 08:01 PM

Quote:

I tried last night (3/5/13) with a pair of Celestron 15x70 binoculars, but I was unable to spot it. (I'm at 30 degrees N. Latitude.) There was too much murk and clouds on the horizon. I will try again tonight with the bino's, since it is much clearer today. Plus, I have an old CG3 mount w/clockdrive and my camera mounted on it that I plan on using to take some images. I might get lucky.




Good luck Mike. I found a clear open view to the west on the way home from work last night at an abandoned road that dead ends into an open field. I can see the california coast mountains heading toward the bay area maybe 60 miles away. Im carrying my new 25 x 100 Orbies with me every evening now in hopes to catch an early glimpse and this weekend plan to set up my 180mm F/6 APM scope out there with my 41 pan and 2" swan band filter. Its show time!

...Ralph


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dan777
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: REC]
      #5717244 - 03/06/13 08:45 PM

Quote:

Just saw it tonight at 6:30 pm in NC.




Thanks for the heads-up Bob. Looks like I might have a shot at it this Friday.


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Foehammer
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RolandosCY]
      #5717628 - 03/07/13 01:32 AM

Quote:

Has anyone spotted it in the evening twilight yet from northern latitudes? No luck yet at 35N...




Was attempting just that yesyerday evening with those crystal clear conditions we had. No luck! Will attempt again today if conditions hold!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave Mitsky]
      #5717938 - 03/07/13 08:58 AM

Hi Everyone,

I attempted for the past 2 evenings, but clouds and haze to the west prevented seeing it again.

From my seeing notes and with the clear skys this morning I am hopeful for this evening.

I am at 20 d 53.572 and 100 d 45.962 at 1904 meters elevation with a totally clear view across our lake...

Will post again this evening.

Very Best Regards,

Preston


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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RolandosCY]
      #5717957 - 03/07/13 09:13 AM

Quote:

Has anyone spotted it in the evening twilight yet from northern latitudes? No luck yet at 35N...




I originally posted this in another thread, but I had no problem finding it from 33 N during March 6's twilight. I snagged a couple of pictures with my point-and-shoot camera and posted them online at http://www.flickr.com/photos/benbrowning/sets/72157632937591972/.

To see it I ended up using a topographical map to find a local ridge about 35 minutes away from my house. But, after seeing how high it was when first visible (almost 4 degrees above the horizon) I'm fairly certain I could have seen it from the top of a parking garage in our little downtown square.

Weather permitting I plan to take my 80mm refractor to the parking garage tonight and grab some better pictures.


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RolandosCY
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Foehammer]
      #5717984 - 03/07/13 09:32 AM

Quote:

Quote:

Has anyone spotted it in the evening twilight yet from northern latitudes? No luck yet at 35N...




Was attempting just that yesyerday evening with those crystal clear conditions we had. No luck! Will attempt again today if conditions hold!



Depending from where you searched, it should had been visible. I tried from the roof at Acropolis through openings between the tall buildings (no time to go outside Nicosia). At 18.01 I could spot stars of magnitude 3 with my 15x70s, but I believe the comet was hidden behind the Pahit-ice court. Maybe we'll get an opening in the clouds tomorrow, as Saturday is again [predicted cloudy.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5718007 - 03/07/13 09:46 AM

Ben, I'm at bit perplexed by your posted images of PanSTARRS from last evening. From the images the apparent direction of the tail is contrary to what it should have been. In your images the "tail" seems inclined decidedly toward the northwest at perhaps a 45 degree angle (to the image's right). The calculated direction for the tail last evening should have had it pointing toward the southwest at about a low 30-40 degree angle (toward the image's left). Did you happen to follow the object long enough to clearly see that it shared in the diurnal rotation of the sky?

I would be very interested to see if you can spot and image the comet this evening and get the same appearance.

BrooksObs

Edited by BrooksObs (03/07/13 09:48 AM)


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stargazer424
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5718024 - 03/07/13 10:02 AM

How high in the sky will it get? I live in NJ and haven't seen a comet since Hale-Bopp in 1997. I am really looking forward to trying to see this one and ISON later this year.

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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5718044 - 03/07/13 10:13 AM

I was perplexed by the tail direction as well, as the finder chart images I've seen on Sky and Telescope's website (http://www.skyandtelescope.com/observing/highlights/185665152.html) show the tail should be facing southwest as you said. These images have been rotated and cropped (but not mirrored) from what was originally captured on the camera, and I have a few more that didn't bring out enough detail to bother posting. I'll look over all of them again and see if I can process them in some useful way to highlight the object's movement over time.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5718101 - 03/07/13 10:41 AM

Hi Ben, That looks exactly like what I saw on March 4ht at 6:50pm as far as size...a bit lower, but it is pointed in the wrong direction...I think your image got flipped...

Visually it was pointed the opposite direction toward the sun.

Wish I had thought to take a pic with my point and shoot.

The weather here Monday evening we very clear due to the northern that had passed through over the weekend with freezing weather...but it cleared out all the clouds and haze.

Best Regards,

Preston

Edited by PrestonE (03/07/13 11:27 AM)


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Mike B.
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5718245 - 03/07/13 11:45 AM

Quote:

Quote:

I tried last night (3/5/13) with a pair of Celestron 15x70 binoculars, but I was unable to spot it. (I'm at 30 degrees N. Latitude.) There was too much murk and clouds on the horizon. I will try again tonight with the bino's, since it is much clearer today. Plus, I have an old CG3 mount w/clockdrive and my camera mounted on it that I plan on using to take some images. I might get lucky.




Good luck Mike. I found a clear open view to the west on the way home from work last night at an abandoned road that dead ends into an open field. I can see the california coast mountains heading toward the bay area maybe 60 miles away. Im carrying my 20x80 binos with me every evening now in hopes to catch an early glimpse and this weekend plan to set up my 180mm F/6 APM scope out there with my 41 pan and 2" swan band filter. Its show time!

...Ralph




Ralph, I struck out again (on Wed, Mar 6th, 2013.).

The sub-tropical jet stream moved in and was pushing lots of high altitude clouds from the west-southwest, exactly where the comet would have been. It was clear for most of that day, too. Oh, well...

I have one more clear evening before it clouds up for some rain forecast for this weekend. It is supposed to be clear again on March 12th, just in time to catch Comet Panstarrs and the moon low in the west. Hopefully, I'll see it then if I don't get to see it tonight.


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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Mike B.]
      #5718289 - 03/07/13 12:00 PM

Given that the tail directions in my picture looks wrong and I cannot find any conclusive evidence to refute that, count me out as someone who has seen the comet. While I very well may have seen it in binoculars, I cannot be sure. I'll try again tonight.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5718421 - 03/07/13 01:14 PM

Hi Ben,

Tony Flanders with Sky & Telescope just replied to an email that I sent to him this morning with your pictures attached.

He is thinking that it is a con trail as between the two pictures the clouds moved a great deal and also the imaged item.

Take a look at the dim white structure on the hill side and the relation of the imaged item in the two pictures...it has moved TOO much against the background to be the comet.

This may explain some things...hopefully tonight we all have clear skys!!!!!!!!!!

Very Best Regards,

Preston


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5718424 - 03/07/13 01:16 PM

Yes, Ben, after initially looking at the two images earlier my first impression was that they were of very distance aircraft con trails seen in greatly foreshortened perspective, especially given the observing circumstances you had reported (detected very shortly after sunset, but so obvious that the object could be easily photographed, with a simple camera, inferring a magnitude probably as or even brighter than Venus).

Actually, I've see these sorts of "comets" from time to time around sunset too since I'm located ~75 miles north of the metro airports in a good spot for viewing flight paths of departing planes headed west at an extreme distance.

BrooksObs

Edited by BrooksObs (03/07/13 01:18 PM)


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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5718456 - 03/07/13 01:39 PM

I appreciate all the feedback, and in the future will definitely post my pictures up for comments before jumping to conclusions. So far the forecast for tonight is clear so I'll get another chance but I had too many issues with the location from last night that I'll try my luck on top of a parking deck instead.

I'll be back out with binoculars and with my 80mm refractor and DSLR already setup just in case the opportunity presents itself for a conclusive image.


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Phillip Creed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5718468 - 03/07/13 01:45 PM

Dear C/2011 L4,

Please have a Comet Holmes-style outburst sometime in the near future.

Sincerely,
Everyone Reading This



(hey, one can always hope for the ol' 15-magnitude bump in brightness)

Clear Skies,
Phil


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5718560 - 03/07/13 02:29 PM

Quote:

Dear C/2011 L4,

Please have a Comet Holmes-style outburst sometime in the near future.

Sincerely,
Everyone Reading This



(hey, one can always hope for the ol' 15-magnitude bump in brightness)

Clear Skies,
Phil




Man, wasn't comet holmes incredible!

...Ralph


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5718634 - 03/07/13 03:08 PM

Quote:

swan band filter. Its show time!




Given that Pan-STARRS is predominantly a dustly comet I'd doubt the SWAN band filter will help much at all.

Now comet Lemmon (still in southern skies) is a comet that would benefit - its has a large green coma - perfect!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5719278 - 03/07/13 08:26 PM

Broken clouds to the west...just packed it in...no recovery of the comet...

Our weather forecast for the coming week is bad...thus, it will only be with very good luck that we see it again.

Best Regards,

Preston


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: PrestonE]
      #5719301 - 03/07/13 08:36 PM

Amazingly, despite a forecast of "fog," we had mostly clear skies this afternoon into sunset, with just some small, thin bands of clouds to the west. However, the sky was not as transparent as I would have hoped that direction.

I started a couple minutes before sunset, and took about 40 frames of still pictures over the next 25 or 30 minutes. In between shots, I scanned the area where the comet should have been, memorizing it's distance away from the sun, and elevation above it.

Alas, it was to no avail; there was nothing to be seen of the comet. I even went back to the still frames and played with the brightness and contrast, zooming in on the area it should have been. No trace of it, visually or photographically. I'm hoping for clear skies tomorrow, but then I'm in for rain for several days, at least.


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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: magic612]
      #5719314 - 03/07/13 08:44 PM

So I had nice clear skies again tonight but the haze in the western direction for the first 1-3 degrees above the horizon was substantial. Despite this, I'm hopeful that I may have captured the comet about 20 minutes after sunset just about 2-3 degrees above the horizon.

I first found what I believe to be the comet in binoculars with the help of a compass and a laptop w/ Stellarium up to monitor the current location of the comet. I then slewed my scope to it with the DSLR attached and captured the following video at 5x LiveView: http://www.youtube.com/watch?v=VGT-oL8b3mA

The object I believe is the comet is barely visible starting in the lower right quadrant of the video and moving upwards as time goes on. "Up" in the video is shown by the partial cellular tower in the top left corner of the video. The tail is pointing the right way and the object definitely had a slightly different apparent motion than the stars since during the video my mount was tracking the stars.

In the video I believe if you look closely you can see the nucleus and two tails. I'm fairly certain this is not a contrail - I almost got fooled by one of those earlier tonight but through the telescope the movement of the plane was obvious as was the swirling of its exhaust gases.

Feedback is welcome.


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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5719337 - 03/07/13 08:54 PM Attachment (57 downloads)

Here's a single image taken out of that video with a tiny bit of processing to dial down the red background and try to bring out the object's detail.

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Unknownastron
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5719356 - 03/07/13 09:00 PM

No joy tonight on this comet. As entropy would have it there were clouds very low on the horizon in the southwest, exactly where I needed to look. I scanned the area for a half-hour with 10x50 binos from about 5 minutes post sunset on, but no definites, maybes or possibles. Forecast for next 2 or 3 days for southern Oklahoma not promising but I will look catch as catch can. Hope somebody has better luck.
Clear skies and clean glass,
Mike


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AlaskaIsCold
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Unknownastron]
      #5719737 - 03/08/13 12:48 AM

Still clouded in here at Anchorage, Alaska.

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eros312
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: AlaskaIsCold]
      #5719767 - 03/08/13 01:28 AM

Still no joy here in Tampa. Crystal clear skies.

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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: eros312]
      #5719796 - 03/08/13 02:27 AM

Bad weather also here in Europe....

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5719840 - 03/08/13 04:11 AM

The BBC has woken up to this event. Poor marks for a headline that the comet will be 'lighting sky', and zero marks for the star chart graphics with the comet tail in the totally wrong direction. Lots of points to Terry Lovejoy who got his picture in the piece.

http://www.bbc.co.uk/news/science-environment-21701641

UPDATE - they get some points back after redoing the graphic and a) scaling down the size of the tail and b) pointing it in the right direction


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5719842 - 03/08/13 04:18 AM

Quote:

Here's a single image taken out of that video with a tiny bit of processing to dial down the red background and try to bring out the object's detail.




Do you mean that dark almost black smudge?? If so that is NOT a comet. Anything beyond the atmosphere has to be brighter than the background to be visible. Anything that is darker than the background is well within the atmosphere and is providing a silhouette to the background sky.

Weres the horizon in this video? If its towards the bottom your black smudge is rising and not setting and finally the black smudge remains equidistant with the edge of the mast through out the whole sequence which strongly suggests whatever it is, its attached to the Earth. Possibly something on a wire strung from the mast?


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: magic612]
      #5719935 - 03/08/13 07:31 AM

Quote:

Amazingly, despite a forecast of "fog," we had mostly clear skies this afternoon into sunset, with just some small, thin bands of clouds to the west. However, the sky was not as transparent as I would have hoped that direction.

I started a couple minutes before sunset, and took about 40 frames of still pictures over the next 25 or 30 minutes. In between shots, I scanned the area where the comet should have been, memorizing it's distance away from the sun, and elevation above it.

Alas, it was to no avail; there was nothing to be seen of the comet. I even went back to the still frames and played with the brightness and contrast, zooming in on the area it should have been. No trace of it, visually or photographically. I'm hoping for clear skies tomorrow, but then I'm in for rain for several days, at least.




This makes me feel so much better about the continuous lousy overcast sky's in Connecticut- and the 8" or so of snow this morning.

Pete


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Djarum
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: azure1961p]
      #5720022 - 03/08/13 08:39 AM

Here in Huntsville, AL, I have a perfect unobstructed view..no dice. Maybe in the next few nights. 34.7 is my rough latitude.

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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5720081 - 03/08/13 09:14 AM

Quote:

Quote:

Here's a single image taken out of that video with a tiny bit of processing to dial down the red background and try to bring out the object's detail.




Do you mean that dark almost black smudge?? If so that is NOT a comet. Anything beyond the atmosphere has to be brighter than the background to be visible. Anything that is darker than the background is well within the atmosphere and is providing a silhouette to the background sky.

Weres the horizon in this video? If its towards the bottom your black smudge is rising and not setting and finally the black smudge remains equidistant with the edge of the mast through out the whole sequence which strongly suggests whatever it is, its attached to the Earth. Possibly something on a wire strung from the mast?




Yes, I mean that almost black smudge. However, my processing of that single image to make it stand out is what makes it look that black. In the original images, it's more of a grayish color.

The horizon is towards the bottom left corner of the image. The object definitely looked to be setting to me. It just looks like it's setting a bit slower than sidereal time which gives the apparent upward motion throughout the frames of the video.

Measuring the distance to the tower of a few frames, the object may or may not be attached to the tower at a static distance. I get different distance measurements from different frames but it's things like 24' separation between the object and a fixed point on the tower vs 26' separation - possibly within the margin of error and not conclusive.

Let me pose a broader question - what would the comet look like as seen through large portions of the Earth's reddish atmosphere after sunset? If it's not found before it gets into the haze, would you expect much or any of the tail to be visible? What color? What angular size?


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5720146 - 03/08/13 09:50 AM

I offer below my weekly update concerning analysis of Comet PanSTARRS' brightness behavior.



The data presented in the graph, based on selected observations, many by the southern hemisphere's most experienced comet observers, represents the comet's brightness corrected for its changing distance from Earth and its progressive, rather methodical, brightening as it approached the Sun. Once again it is noted that this trend has been in a perfectly predictable and unchanging manner, as it has since the opening of the year. Dramatic alteration in the comet's rate of brightening, claimed by some other sources, is clearly shown to be untrue. The comet should currently have reached its peak brightness as seen from Earth and is anticipated to very shortly begin a steady fading trend as it withdraws from the Sun and Earth.

BrooksObs

Edited by BrooksObs (03/08/13 09:52 AM)


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5720200 - 03/08/13 10:21 AM

Quote:

it's more of a grayish color




It most certainly would not look grey. What you have in the video is not the comet.

Quote:

what would the comet look like as seen through large portions of the Earth's reddish atmosphere after sunset?





What it would look like is distinctly brighter than the local sky, coloured anywhere from pale yellow, through oranges to pink depending on the level of reddening imparted by the thick atmosphere. The psuedo nucleus will be the brightest portion and look almost stellar and more (pale)yellow - a point of light at the head.

Back in early Jan 2007 this is exactly how I observed McNaught as it brightened enough to become visible in deep twilight sky for the brief viewing window we had in the northern hemisphere


Quote:

would you expect much or any of the tail to be visible?




The tail gets dimmer as you move away from the comet nucleus. Until the comet gets high enough above the horizon at sunset you will always get a greatly truncated version as it fades to blend with the background sky and disappear.

Again McNaught in Jan 2007 did just this. My first observation in bright twilight on the 5th Jan was the stellar psuedo nucleus surrounded by just a few arc minutes of coma fuzz with a hint of elongation, on the 6th the coma was distinctly elongated and about 7 arc mins, on the 10th the tail was now bright enough to emerge from the twilight and appeared just over 2 degrees in length when the comet was 3 degrees above the horizon and got to about 3 degrees as the skies darkened. However the comet was now setting. On the 14th the comet was too close to the sun (< 6 degrees) that the only part we saw was the bright stellar central portion in the daytime sky (the comet was about mag -5 that day)

Otherwise I can only advise that no way CAN the comet appear darker than the surrounding sky. If its not bright enough you just won't see it (after all the daytime sky is not peppered with grey spots where stars should be).


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guangtou
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5720262 - 03/08/13 10:49 AM

I also have a clear view of the horizon in North MS- nothing but contrail decoys! I scanned with 15x and 8x binocs and took shots @ 70mm.

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: guangtou]
      #5720332 - 03/08/13 11:33 AM

I found this today that compares the size of Pan-STARRS with the last "great" comet Lovejoy (C/2011 W3) a couple of winters ago

http://i727.photobucket.com/albums/ww271/Rob_Kau/L4W3scaledimages.jpg

Pan-STARRS is puny!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5720402 - 03/08/13 12:11 PM

Going to try at sunset tonight - I'm at 43.6° latitude, so I'm not going to get my hopes up. The comet will only be 10° above the horizon at sunset. It'll be clear tonight, so I might as well give it a shot.

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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5720409 - 03/08/13 12:13 PM

Quote:

I found this today that compares the size of Pan-STARRS with the last "great" comet Lovejoy (C/2011 W3) a couple of winters ago

http://i727.photobucket.com/albums/ww271/Rob_Kau/L4W3scaledimages.jpg

Pan-STARRS is puny!




since were astronomers and like to use our gear, its plenty good enough for me. I like to see things using my scopes or binos.

...Ralph


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Mike Lynch
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5720569 - 03/08/13 01:38 PM

PHOTOGRAPHED FROM THE NOTHERN HEMISPHERE--IF JUST BARELY!!

Check the photo from a Malaysian photographer at 5 degrees N: http://www.spaceweather.com/

Mike Lynch
Frankfort KY USA


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Mike Lynch]
      #5720614 - 03/08/13 02:02 PM

Nice one, but a little too low yet for most of us. Looking forward to it.

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Ben B
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5720622 - 03/08/13 02:07 PM

Quote:

Otherwise I can only advise that no way CAN the comet appear darker than the surrounding sky. If its not bright enough you just won't see it (after all the daytime sky is not peppered with grey spots where stars should be).




Thanks for the detailed explanation - looks like I may get one more clear sky chance tonight before bad weather moves in.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5721210 - 03/08/13 09:03 PM

No luck here from Ohio tonight. I tried it from a parking lot at Malone University, one of the highest points in all of Stark County. I brought my quick-strike, "guerilla astronomy" set-up of 15x70 Oberwerk binoculars and an alt-az mounted 8" f/4.9 Newtonian. I scanned the bright twilit skies to no avail.

Whatever its brightness, it is definitely not negative-mag.

Clear Skies,
Phil


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Dave M
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Phillip Creed]
      #5721232 - 03/08/13 09:12 PM

Phil,

I had the same exact results as you. I scanned the horizon
with 7x50 binoculars for a good 45minutes, i gave up after 7:20 pm..


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5721270 - 03/08/13 09:42 PM

I also looked for PanSTARRS tonight from 7:00 PM local until 7:30 but no joy. My wife looked too (she has hawk like visual acuity) but we saw nothing with the unaided eye or with the 12x36 IS binoculars.

I maybe should have started a little earlier--a distant mountain blocked the view up to ~5°--but the sky was awfully bright.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5721424 - 03/09/13 12:07 AM

I looked for C/2011 at around 1830 to 1900 with my 10x50 Pentax binos and could see nothing. Albeit, my horizon was not so great with trees and whatnot. My latitude about 35. I was fooled a couple times by some contrails...

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Scanning4Comets
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5721430 - 03/09/13 12:11 AM

Hopefully we will ALL get a peek at this comet!

Cheers,


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Scanning4Comets]
      #5721478 - 03/09/13 01:00 AM Attachment (24 downloads)

No luck here tonight at 38 deg latitude in Sacramento. I was set up by 5:30pm just as the sun was going down, and finally called it quits at 7:30pm. There was some very very low lying muck in the western horizon and some tiny bits of clouds that were breaking up. I'm convinced this is a very small dim object, since I really never heard any detailed visual descriptions of this comet about its overall size and brightness, even from the southern hemisphere observers.
Nevertheless, I scanned the skies with my 6" F/5 Celestron Omni 150r as soon as the sun dipped below the horizon using my Bogen heavy duty tripod which seemed ideal for this type of observing. I varied my eyepieces from a 41 Panoptic to my 12 Nagler, and every Nagler in between, hoping some of the higher magnifications would detect anything. I even studied every tiny speck of clouds in details, thinking some of these specs could actually be the comet.
Despite having a ton of fun doing this, with my sports radio playing, I saw absolutely nothing.
Fortunately, these next two nights are showing clear crisp skies, from right now till Monday, so I'll be back at it, both evenings again.

Straight thru viewing, without any 90 deg or Erect Imaging diagonal seemed to be the most effective way to scan the horizon.

Good luck to all you comet hunters!!

.....Ralph
Sacramento, Calif
(38º 34' N, 121º 29' W)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5721508 - 03/09/13 01:37 AM

Those of us who are clouded out, do not despair - yet. I've not been able to sight PanSTARRS either through binoculars (a 7x35) or unaided eyes even though we have had perfect skies since three days in a row, with only very low horizon haze on Wednesday evening. The shot of the comet from Malaysia (5N) perhaps explains that.

The western horizon for our rooftop is quite unobstructed, with a few under-construction, far off buildings blocking some tiny portions of the sky:




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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5721537 - 03/09/13 02:46 AM

fizzle?

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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Yaar]
      #5721624 - 03/09/13 04:28 AM

Its not really supprising that no-one is seeing anything - a case of pulling trigger far too early. E.g. last night Pan-STARRS would have been 1/2 degree above horizon at start of nautical twilight at 40 N

Tonight its 2 degrees at start of NT, day after is 4 degrees at NT, then 6, 7, 8, 9 and 10 degrees on 15th March

Quote:

fizzle?




Certainly not - just everyone looking when its improbable to see.

I recon first observation below 40 N *might* be tonight - low probability. Better chance the day after - otherwise 12/13th will be much easier as very very thin moon is nearby


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5721636 - 03/09/13 04:49 AM

We are all jumping the gun but that's what we like to do. Since it only takes a few hrs of our time from start to finish, its pretty fun. Im going out tonight and tomorrow also, tonight because its going to be a clear new moon weekend, and Sunday night because I can still get home by 8pm. after that, we are getting a full week of cloudy weather so its now or never, or at least now till the following week when everything clears up again! Tonight its just across from Mars, so if you can find Mars, PannStarr should be right there.

...Ralph


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5721683 - 03/09/13 06:46 AM

Quote:

Its not really supprising that no-one is seeing anything - a case of pulling trigger far too early. E.g. last night Pan-STARRS would have been 1/2 degree above horizon at start of nautical twilight at 40 N

Tonight its 2 degrees at start of NT, day after is 4 degrees at NT, then 6, 7, 8, 9 and 10 degrees on 15th March...






Tony, thanks for the info. I guess you meant the end of nautical twilight (when the center of the Sun is 12° below the western horizon), not the start?

By those calculations, for me the comet would have been 2.5° above the horizon at the end of NT and behind a mountain.

Bragging rights are a powerful motivator.


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5721737 - 03/09/13 07:51 AM

Quote:

I guess you meant the end of nautical twilight




No - start - end of civil twilight if you like


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pogrzex
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5721738 - 03/09/13 07:51 AM

The comet is now visible to STEREO probe.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5721740 - 03/09/13 07:57 AM

I was going to head back over to my good-western-horizon location last night, but enough cirrus clouds had settled in over the western horizon I knew there wasn't any point. The only really frustrating thing? There were no clouds on the horizon to the north, east and south.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: magic612]
      #5721846 - 03/09/13 09:17 AM

The local club is hosting a public/members event Tuesday evening when the comet will be beside the thin crescent moon. Location is beside a city reservoir with a nice flat western horizon. While I join in hopes that PANSTARRS will be a decent naked eye object, so far it's not looking that way. However, it should remain as a better than nothing at all telescopic target into April as it climbs out of the sun's gravity well and becomes circumpolar, with projected encounters with M31 and Polaris. It will be nice to have a fuzzball comet on those nights even though it will have probably shed most or all of its tail and be down into mag 4-6 range. That's still better than most comets.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: buddyjesus]
      #5722268 - 03/09/13 12:49 PM

A friend and I looked from 6:45 till 7:20 with a couple of small clouds...nothing

Will be trying yet again tonight...guess what I saw last Monday was not the comet but a contrail.

Best Regards,

Preston


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: PrestonE]
      #5722317 - 03/09/13 01:15 PM

Someone on the Southern Stars Yahoo Group saw it last night using a C-11 scope. He found Mercury, and then did a short GoTo to the comet. He said he just saw the inner coma, maybe 20 arcsec across. Estimated brightness about 1.2. He said it was not an easy target.

He was in West Texas.

Edited by btschumy (03/09/13 01:17 PM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: btschumy]
      #5722502 - 03/09/13 03:38 PM

Quote:

Someone on the Southern Stars Yahoo Group saw it last night using a C-11 scope. He found Mercury, and then did a short GoTo to the comet...




Do you mean Mars?


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5722528 - 03/09/13 03:54 PM

Quote:

Quote:

I guess you meant the end of nautical twilight




No - start - end of civil twilight if you like




OK, that would put the Sun 6° below the horizon at 6:50 PM local and the comet far down behind the mountain 10 minutes before I even started looking.

According to your numbers, PanSTARRS will be 4° above the horizon at my location (38°N) at the start of NT (6:48PM local this evening). Local sunset is 6:23PM so that tells me I'd better get out there and look much earlier than I anticipated.

I'm going to try and spot Mars and then key off of the Red Planet for PanSTARRS. The sky will be bright so I am not optimistic but it's clear today and that won't last.

Thanks again for the info.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5722574 - 03/09/13 04:18 PM

Quote:

Do you mean Mars?



Oops. Yes, Mars.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: btschumy]
      #5723083 - 03/09/13 10:18 PM Attachment (18 downloads)

Thanks, Bill.

I struck out again tonight (Saturday). Our clear forecast went south and was replaced with plenty of high clouds. I tried anyway beginning 5 minutes after local sunset looking for a half hour with the 12x36's but could not see Mars or the comet. Saw plenty of contrails, though. Here's an example:


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: btschumy]
      #5723085 - 03/09/13 10:21 PM

Tried this evening in as close to perfect conditions (40N, 75W) as I've ever had near the very low western horizon. Sun set around 6:02pm EST. Scanned appropriate area for nearly an hour - nothing but jet contrails (LOTS of them). Another guy pulled into the parking lot I was using and immediately assumed the brightest contrail was "that starry comet". I tried to explain about extinction due to altitude, likely appearance, etc - he just wasn't buying it.

So a big negative with naked eye and 7x50s this evening in NJ.

Grant


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RedLionNJ]
      #5723093 - 03/09/13 10:27 PM

No luck for me either (37N 122W), but I arrived after sunset so didn't have a reference from the sun/moon to base a reference on. Perhaps tomorrow(sun).

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RedLionNJ]
      #5723113 - 03/09/13 10:44 PM

I'm still out with my 6" F5 Celestron observing in a straight thru configuration with my 26 nagler and again with my bogen tripod. At 6:50 pm I found PannStarr. It was very small, I would say maybe 20 arc minutes long with a very bright coma. It was maybe 3 deg above the horizon and the skies were not completely dark. I held my cell phone up to my eyepiece and took a very grainy off center photo of it through my eyepiece. It was barely visible in the photo but definately there. I'll edit this message later with the photo attached. I tried but could not.detect it with my 10x42 nikons, but I was.definitely running out of time because it quickly dipped behind some very low clouds. Mars was visible.to the right of PannStarr. The skies are to perfect to call it a night right now, but I do have a laptop with me and will try and edit the cheesy photo in a bit. Despite all of this, it was very cool to observe. I really don't think small.binos could detect it tonight.
This is being sent from my smartphone.

...Ralph in Sacramento (38 deg latitude)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: wfj]
      #5723114 - 03/09/13 10:47 PM

I had a western horizon almost as good as an ocean this evening, cloudless, hazeless skies - watched the sun set, Mars was just visible in the binos. Comet should have been about 7 degrees south and 2 degrees higher up - nothing astronomical visible in that area. Maybe tomorrow or Monday...

Grant


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RedLionNJ]
      #5723115 - 03/09/13 10:49 PM

I'm still out with my 6" F5 Celestron observing in a straight thru configuration with my 26 Nagler and again with my Bogen tripod. At 6:50 pm I found PannStarr. It was very small, I would say maybe 20 arc minutes long with a very bright coma. It was maybe 3 deg above the horizon and the skies were not completely dark. I held my cell phone up to my eyepiece and took a very grainy off center photo of it through my eyepiece. It was barely visible in the photo but definitely there. I'll edit this message later with the photo attached if its worth showing. I tried but could not detect it with my 10x42 Nikons, but I was.definitely running out of time because it quickly dipped behind some very low clouds. Mars was visible.to the right of PannStarr and not nearly as bright as PannStarr was, at least through a 6" refractor. The skies to are too perfect to call it a night right now, but I do have a laptop with me and will try and edit the cheesy photo in a bit. Despite all of this, it was very cool to observe. I really don't think small binos could detect it tonight.
This is being sent from my smartphone.

...Ralph in Sacramento (38 deg latitude)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723198 - 03/09/13 11:47 PM

I thought I saw it, but am somewhat less confident now that all the negative reports have come in. It was about where it should have been, a short, very well-defined stub, sort of like I saw McNaught a few years back, but pointing hard to the south, a little before 10 o'clock on a clock face, relative to the horizon. Also, unlike a contrail, it set behind a hill rather than simply dissipating, fading, or blowing toward us with the wind.

Hard for me to judge size or brightness, because I couldn't see it with the naked eye and didn't have time to measure it relative to objects on the horizon. Saw it for only a few moments, within about fifteen minutes of the sun dropping behind the distant hills.

Anyway, I'll be trying again from the same spot tomorrow, so if it's clear, I'll know for sure then.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Zebra24601]
      #5723239 - 03/10/13 12:19 AM Attachment (91 downloads)

I posted this in "General Observing" but I'll add it here too if that is okay.


LOL, well I caught it! I was expecting a lot more from this effort and actually just stopped laughing my head off. But here's my meager capture from San Clemente Pier (Catalina Island in the background).

It helps to squint really hard. LOL!!!!


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723243 - 03/10/13 12:20 AM Attachment (85 downloads)

And here is the full frame image. Nikon D800, 20 seconds, f11, 135mm.

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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723260 - 03/10/13 12:29 AM Attachment (66 downloads)

and here is another frame (extreme crop) showing an airplane passing just below.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Zebra24601]
      #5723278 - 03/10/13 12:55 AM

Quote:

I thought I saw it, but am somewhat less confident now that all the negative reports have come in. It was about where it should have been, a short, very well-defined stub, sort of like I saw McNaught a few years back, but pointing hard to the south, a little before 10 o'clock on a clock face, relative to the horizon. Also, unlike a contrail, it set behind a hill rather than simply dissipating, fading, or blowing toward us with the wind.

Hard for me to judge size or brightness, because I couldn't see it with the naked eye and didn't have time to measure it relative to objects on the horizon. Saw it for only a few moments, within about fifteen minutes of the sun dropping behind the distant hills.

Anyway, I'll be trying again from the same spot tomorrow, so if it's clear, I'll know for sure then.




You absolutely saw it. The description of the tails direction was spot on with what I saw, although in the straight through configuration that I had with my 6" refractor with no diagonal installed, my bearings are completely screwed up as to which direction is which. I saw a nice wide tail which fanned out, much wider than the bright coma. The coma had a bright star like center with plenty of fuzz around the coma, and the tail fanned out quite nicely. Again, this was my observations with my 6" F/5 refractor. Within about 5 minutes after I saw it, it dipped behind some very low clouds, then reappeared for about 2 minutes, then dipped below the horizon. I panned to the right and saw Mars.
I think it was very cool to see. I have a hard time hearing that people are disappointed in what it looks like, I think it was incredible.

...Ralph


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723285 - 03/10/13 01:02 AM

Quote:

and here is another frame (extreme crop) showing an airplane passing just below.





Hey Jay,

I'm gonna have to question that photo because there is no visible coma in that photo, and the views i saw of the comet tonight had a very very bright coma, very star like, compared to the tail, and the tail I saw fanned out away from the coma. The tail was nearly as wide as the length of the tail, at least during the twilight time when I saw it.

If i was to say, Id say that was not it!

...Ralph


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723295 - 03/10/13 01:14 AM

What time was the image taken ? Myself and a friend tried to spot it in 11x80's and 10x50's but no luck from up in the foothills above Monrovia tonight.

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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723296 - 03/10/13 01:15 AM Attachment (34 downloads)

well, you may be right but i have multiple 20 second exposures where this object appears in the same spot. in fact, the detail shot with the airplane below is a separate shot from the one above.

Jay

on edit: 135mm lens has an angular size of about 15º wide x 10º tall. This image shows Comet PanSTARRs about 3º above the horizon at approximately 6:32 pm PST.

Edited by Jay (03/10/13 03:32 AM)


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723302 - 03/10/13 01:26 AM Attachment (24 downloads)

airplanes seem to be moving but not this fuzzy

Edited by Jay (03/10/13 01:30 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723314 - 03/10/13 01:36 AM

Quote:

well, you may be right but i have multiple 20 second exposures where this object appears in the same spot. in fact, the detail shot with the airplane below is a separate shot from the one above.

Jay




Honestly, I think that's too high up in the sky for tonight, especially after the sun went down. PannStarr was only 3 or 4 degrees above the horizon tonight and again, there's no visible coma. The bright coma is what catches your attention first when its visible.

...Ralph


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723319 - 03/10/13 01:42 AM

Here's my data from Starry Night Pro set for March 9 at my location. Much higher than 3 or 4 degrees here in Southern California.

March 9th, 2013
_____________________________________

Sunset: 5:53 PM
_____________________________________

Sun at 5:49 PM AZ 265º

PANSTARRS AZ 258º ALT 11º
_____________________________________

Comet Set: 6:46 PM AZ 263º
_____________________________________


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723324 - 03/10/13 03:01 AM

It does look high, but he's shooting with a 135mm telephoto. What I thought I saw looked an awful lot like these picture: Very thin, very straight, no coma visible. I was using 12x60 binoculars, though, so everything's going to look pretty small. Also, the sky was still pretty bright.

I'm working tomorrow, but I'm going to try to take a break just around 6pm and look for PanSTARRS, again. If it's clear, it should be easier and I'll be more certain. If I can't get a break then, I'll try again on Monday evening, someplace with a clear western horizon.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Zebra24601]
      #5723332 - 03/10/13 03:18 AM Attachment (64 downloads)

Here's a shot taken at about ten minutes after those posted above. About 6:40pm. Another 20 second exposure and an extreme crop.

On edit: This shows this object about 2.5º above the horizon.

Edited by Jay (03/10/13 05:15 AM)


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723335 - 03/10/13 03:20 AM

Quote:

Here's my data from Starry Night Pro set for March 9 at my location. Much higher than 3 or 4 degrees here in Southern California.

March 9th, 2013
_____________________________________

Sunset: 5:53 PM
_____________________________________

Sun at 5:49 PM AZ 265º

PANSTARRS AZ 258º ALT 11º
_____________________________________

Comet Set: 6:46 PM AZ 263º
_____________________________________




I've been observing comets for the last 30 years and Ive never seen a comet without a coma. Ive seen plenty of comets without tails, but none without coma's. Also, your 135mm camera is equivalent to less than 3x in magnification, unless you have a 100mega pixel camera, the comet would never be detectable at that little magnification. You can see from what others are posting out here, in that they are not seeing the comet even in 11x binoculars. My scope was at 26x and it was a small object at 26x. Though its not impossible, It would be very improbably that tonight, PannStarr was detectable in a 3x lens system, which would be more than your 135mm camera lens. People out here were not seeing it with 7 to 11x binoculars. I had my 10x binoculars around my neck and after I detected the comet in my 6" refractor, I looked for it with my binoculars and couldn't see it.
PannStarr is very comet looking, tonight it had a bright starlike coma and a fuzzy area around it, and a wide stubby tail, even in the twilight light that I saw it in.
Maybe because I was using a 6" refracor instead of smaller optics, we are seeing the same thing two different ways? Look for it tomorrow, it will be 2 deg higher, when you see it, you'll know what I'm talking about.
Just remember you wont see it right at sunset, there's too much light then, and it still maybe extremely difficult to detect in a pair of 7x50 pair of binoculars. Cameras can pick up more they eyes can, and if so, the coma should be blaring in your photo.

For those looking for PannStarr tomorrow night, I would strongly recommend using a small telescope instead of low power binoculars.
I do think 20x80x, or 25x 100's binoculars should pull it out nicely. Id not recommend anything below 20x. Just look about 10 degrees to the left of where the sun touches the Horizon, and start panning above that area and look for a fuzzy star until it gets dark enough to detect the tail.


...Ralph


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723341 - 03/10/13 03:37 AM

135mm lens has an angular size of about 15º wide x 10º tall. If you scroll up to the full frame shots they show Comet PanSTARRs about 3º above the horizon at approximately 6:32 pm PST. 36 megapixels is quite enough when you factor in a 20 second exposure.

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723352 - 03/10/13 04:06 AM

even this photo shows a coma:

http://spaceweather.com/gallery/full_image.php?image_name=Rob-Kaufman-IMG_010...

compared to yours:

http://www.cloudynights.com/ubbthreads/attachments/5723260-DSC_2604extremecro...

all I'm saying is, "where's the coma" if its comet PannStarr cuz comet PannStarr has a very obvious coma.

I saw a very obvious coma in my views tonight, and another person who saw it last night also said it had a very obvious coma.

I'm not a photographer, so you would know better than me, but wouldn't a camera pick out the coma even more so than the tail?

that's all I'm saying, because your angle looks correct and everything seems right, but there's no coma.

I'll just leave it at that..

....Ralph


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723358 - 03/10/13 04:26 AM Attachment (29 downloads)

Hi Ralph!

"all I'm saying is, "where's the coma" if its comet PannStarr cuz comet PannStarr has a very obvious coma. "

I can attempt to explain what I captured thusly: Hazy high clouds here (vs transparent skies). 135mm vs. 55mm (huge difference in tracking smear). 20 seconds of blur vs 6.8 seconds. I'm not tracking so any specular stellar point, that isn't already fuzzed out by thin high clouds is going to smear and would not result in highly condensed coma -- especially from a site with transparent skies like the photo you linked us to.

The "object" I've captured is tracking exactly as Stary Night is predicting for Comet PanSTARRs. I respect your 30 years (I've been lucky to have been at this for 40 years too and 30 of those involved professionally as a photographer).

Your friend,

Jay

Edited by Jay (03/10/13 05:11 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723401 - 03/10/13 05:47 AM

It is not the comet dude looks to me like some strange cloud or a fake (no offence) :P

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: pogrzex]
      #5723500 - 03/10/13 08:37 AM Attachment (29 downloads)

Yeah, sorry, these shots aren't the comet. The overwhelmingly bright part of PANSTARRS is the tiny, intense inner coma and if your images show just a tail it isn't the comet. Same for binocular & naked-eye views.

As the comet moves into darker skies over the next week, visually look for a faint 'star' to pop out, in the right position. The tail will reveal itself as the sky darkens. It is visible in binoculars before it is visible naked-eye of course - if you can locate the comet (think 'star'!) with binoculars then this significantly helps locate it naked eye.

It's still just visible from the south and a friend in NSW, Australia, successfully saw it again tonight. I haven't seen it since 6 March due to cloud. My "farewell" shot from that night is attached.

Good luck - hope it puts on a good show & I look forward to your reports & images!

Cheers -

Rob


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5723521 - 03/10/13 08:57 AM

Indeed, the posts by Ralph and Rob are 100% correct. The various astronomy forums this morning are listing all sorts of reports of supposed sightings, along with photos, all actually of short jet con trails reflecting sunlight. As in Rob's photo, when you do finally spot the comet its head will far out-shine the tail. What most observers are totally neglecting to appreciate is the fact that at such low elevations over the horizon atmospheric extinction will be very large, in many cases running to 3-4 magnitudes, or even more, depending on the actual clarity of the air. Now imagine trying to see a star of say 3rd or 4th magnitude against that bright twilight background. Telescopes may well bring it out, but not common binoculars and certainly not the naked eye!

But be patient, PanSTARRS will reveal itself in all its glory in the course of the coming week as its elongation from the Sun slowly increases and its elevation over the western horizon grows. Just the span of 3 or 4 days is going to make a dramatic difference in the comet's visibility from most locations. So, just give the comet a little more time.

BrooksObs

Edited by BrooksObs (03/10/13 09:03 AM)


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5723562 - 03/10/13 09:37 AM

BrooksObs & Rob,

Thanks for helping us out here. Trying to catch this particular comet early has been a toughie.

@Rob, Nice final image. I remember when we passed off Comet McNaught to you southern hemisphere observers back in January of 2007 it was bright as a flare through binoculars during twilight. I know it's not your fault you couldn't do the same for us with PanSTARRS.

@Ralph, congratulations on your sighting--it sounds to me like you saw it.


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723613 - 03/10/13 10:23 AM

Well I'm nuts! I'm setting off in 40 minutes to cross to the western side of the UK to try and catch the comet in a viable 15 minute window. Venue is a high hill overlooking the Irish Sea.

Why - because forecast is rubbish for the rest of the week - and when I did the same long distance expedition way back on 5th Jan 2007 I succeded in catching C/2006 P1 when it was only just bright enought to emerge from twilight when very low. I just want to see if I can repeat that experience!


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723620 - 03/10/13 10:29 AM

Quote:

and Ive never seen a comet without a coma




Theres been a few - recently C/2011 W3 was almost comaless. You can't dismiss this just because you haven't experienced it. Its better to dimiss this if someone else has a validated image on the same date with a coma

Heres the recent comaless comet classic - http://i638.photobucket.com/albums/uu109/Lester_045/Comet%20images/1d5bf314.jpg


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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5723629 - 03/10/13 10:35 AM

Good luck Tony, i hope i can get another shot at seeing it on the 12th or 13th, but right now the weather looks iffy..

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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5723639 - 03/10/13 10:51 AM

Quote:

Its not really supprising that no-one is seeing anything - a case of pulling trigger far too early. E.g. last night Pan-STARRS would have been 1/2 degree above horizon at start of nautical twilight at 40 N

Tonight its 2 degrees at start of NT, day after is 4 degrees at NT, then 6, 7, 8, 9 and 10 degrees on 15th March


Quote:

fizzle?




Certainly not - just everyone looking when its improbable to see.

I recon first observation below 40 N *might* be tonight - low probability. Better chance the day after - otherwise 12/13th will be much easier as very very thin moon is nearby




You are correct Tonk. Panstars just reached perihelion on March 9 and now heads north into view for us in the northern hemisphere. The earliest any one can expect to view this comet in the northern hemisphere is on the 10th of March when it sets about 15 minutes after the sun in a still very bright sky. So good luck trying to see it tonight. I too will be making an effort this evening, weather permitting, It is forcast to be cloudy the next three nights here.


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BrooksObs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Dave M]
      #5723658 - 03/10/13 11:09 AM

I likewise wish you good fortune in your trek, Tonk.

However, just a point of information: Comet's lacking distinct comae are all but non-existent in the literature. Comet Lovejoy was a Sungrazer and these are really a distinct class of objects that do, on occasion, become headless as a result of their complete disruption as they pass through the Sun's Roche Limit for these fragile bodies.

Big, bright, well developed comets like PanSTARRS simply do not experience such events and the recent reported sightings of PanSTARRS as just a "tail" streak are all just mistaken views of very distant jet con trails that look somewhhat like intense comet tails to the inexperienced. The lack of the anticipated far brighter head, or coma, give the mistaken sightings away.

Our skies have become so filled with commercial jets over the years that it has become almost impossible to view a sunset without seeing at least one or two examples at a time very low down in the twilight. So, beware of being tricked if your venture does meet with clear skies.

BrooksObs


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BrooksObs]
      #5723697 - 03/10/13 11:21 AM Attachment (53 downloads)

Well, apparently my contrail image has caused a lot of trauma. My friend here unfriended me on Facebook over it then deleted two of my four images on his Astronomy group there and followed that up with saying I had posted doctored and phony images. I had no idea posting my admittedly crummy image would cause so much drama.

I do want to leave you with a relatively crude composite image before I go however. It's shows my contrail in 8 sequential 20 second exposures. The top image taken at 6:34 pm and the last at 6:43 pm PST. The image is less than 4º tall and shows my contrail about 3.5º above the Western horizon.

The funny thing is, I live on the West Coast where the jet stream travels roughly West to East. I have, apparently, caught one that travels in reverse here.

If anyone is really bored just let me know and I will FTP my RAW NEF files to my web space for you to download and sort through yourself. My reputation is important to me and I would like to be absolved of any wrong doing.

Sorry for all the trouble.

Jay Mason


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MessiToM
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723713 - 03/10/13 11:32 AM

sorry to hear that ^ I think it looks legit.....

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RobK
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723718 - 03/10/13 11:35 AM

Quote:

I remember when we passed off Comet McNaught to you southern hemisphere observers back in January of 2007 it was bright as a flare through binoculars during twilight. I know it's not your fault you couldn't do the same for us with PanSTARRS.






I'm glad we've been able to hand over something Michael, not like the botched job we did on Elenin in 2011! After all the care you showed in handing over McNaught in prime condition too!

Patience and persistence is the key - I've not been able to spot PANSTARRS with binoculars until almost half an hour after sunset. That's in very clear air. Mind you, when you get the first view you think, well, it MUST have been visible a little bit earlier! Once I'd located it, naked-eye views followed shortly afterwards but it's not the sort of comet that you walk out into the backyard, look west and say "Wow, look at that!". It's pretty subtle and quite small in the light sky.

However, it is easy to point out to non-astronomers when gets a bit darker because it's so low. You can tell them to spot the 'star' directly over a bush, tree, particular roof etc and they'll see it. People I showed it to as late as the 5th of March had no difficulty seeing the comet or the tail naked-eye. But without assistance they never would have seen anything.

Cheers -

Rob


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BillFerris
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5723730 - 03/10/13 11:46 AM

Jay, you can test your observation by repeating the photograph, tonight. It's unlikely there will be an identical contrail phenomenon in the same location at the same time on subsequent days so, if you can repeat the observation, that would tend to confirm that your photograph is of the comet. If you do repeat the photograph, try to get an accurate measurement of the azimuth of the object. Confirming the correct location would also support a conclusion that you've photographed the comet. If you repeat the photograph but fail to capture the "streak," that would tend to support the conclusion it was a contrail or other transient, atmospheric event.

It's unfortunate your friend is responding so harshly (unfriending of Facebook? Accusations of fraud? Sheesh.) to what may be a negative sighting of this comet. The fact that you documented your observation and publicly shared the image should be a clear indication that you're open to--welcoming of, in fact--others' objective analysis. If it turns out to have been an atmospheric event captured in your photo, you will still have contributed something of value. Negative sightings help us to better understand what is required for a positive sighting.

Bill in Flag


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5723736 - 03/10/13 11:48 AM

Quote:

Well I'm nuts!




I see you've joined the club. Good luck!


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Tonk]
      #5723753 - 03/10/13 11:57 AM

Quote:

Quote:

and Ive never seen a comet without a coma




Theres been a few - recently C/2011 W3 was almost comaless. You can't dismiss this just because you haven't experienced it. Its better to dimiss this if someone else has a validated image on the same date with a coma






Here it is. Paul Ostwald took this image March 9th ~6:49PM local. Look between the power lines to the right of the tower. Scroll down for more info.


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*skyguy*
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5723765 - 03/10/13 12:04 PM

Quote:

My friend here unfriended me on Facebook over it then deleted two of my four images on his Astronomy group there and followed that up with saying I had posted doctored and phony images.




Misidentifying an object in the sky is an easy thing to do ... even long time observers can make this mistake ... and it's usually an honest mistake. However, accusing someone of "faking" an observation or image is just plain wrong and should not be tolerated without 110% proof of a wrongdoing.


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BillFerris]
      #5723774 - 03/10/13 12:06 PM

Hello Bill,

I intend on shooting again tonight. Here is where I was on the 8th: https://sphotos-b.xx.fbcdn.net/hphotos-prn1/858597_443961562364604_1724517140... I moved North on March 9th to just below the first blue Amtrak marker on the map to get a better pier comet composition but had no idea how dim and small it would turn out.

You can get a very accurate of my bearings from this posted image. It shows the where the sun is setting on March 9th and the coordinates can be verified with any planetarium software. I did not move the tripod. http://www.cloudynights.com/ubbthreads/attachments/5723358-DSC_2503.jpg

I was hoping to shoot using the identical camera and lens configuration from the ridge behind my house tonight. How important do you think it will be for me to head back to the identical March 9th location? I will if matters but since the comet will be higher and further North shouldn't its appearance in the camera be of sufficient proof?

I now know the sting most 14 year old girls are well familiar with... "Unfriending". I think I will get over it... well, I hope I do.

Jay Mason


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: BillFerris]
      #5723779 - 03/10/13 12:09 PM

Quote:

...The fact that you documented your observation and publicly shared the image should be a clear indication that you're open to--welcoming of, in fact--others' objective analysis. If it turns out to have been an atmospheric event captured in your photo, you will still have contributed something of value. Negative sightings help us to better understand what is required for a positive sighting.

Bill in Flag




Jay,

I agree with Bill. It never once occurred to me that the image was falsified and I would venture to guess that's true of 99+% of the rest of us in this forum. The truth is--this bad boy is just hard to spot right now and a lot of us have found that out.

BTW, your widefield shot with the pier is lovely.


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723817 - 03/10/13 12:24 PM

Special Ed

Thank you! It was even lovelier the day before but too many clouds made a comet catch impossible... I did get a better bearing on the sun however and therefore adjusted my location slightly on March 9.

web page https://sphotos-b.xx.fbcdn.net/hphotos-prn1/856832_444379522322808_873032927_...

Jay


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723821 - 03/10/13 12:27 PM

Quote:

...in the straight through configuration that I had with my 6" refractor with no diagonal installed, my bearings are completely screwed up as to which direction is which...I panned to the right and saw Mars...
...Ralph




Ralph,

I got to thinking about this and a refractor with no diagonal would have zero reflections and an upside down view (like a Newtonian reflector). Wouldn't you have had to pan to the left to see Mars? Were you using a GEM or alt/az mount?


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723841 - 03/10/13 12:44 PM

Quote:

Quote:

...in the straight through configuration that I had with my 6" refractor with no diagonal installed, my bearings are completely screwed up as to which direction is which...I panned to the right and saw Mars...
...Ralph




Ralph,

I got to thinking about this and a refractor with no diagonal would have zero reflections and an upside down view (like a Newtonian reflector). Wouldn't you have had to pan to the left to see Mars? Were you using a GEM or alt/az mount?




Your right Ed, I panned to the right to see mars. I was surprised it was so big, I think because it was just above the mountaintops, just a degree or so from my horizons view. It was perfect round balls, even at the 28x i was seeing it as.

I was using my alt/az mount, which made it pretty easy to pan the skies.

...Ralph


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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: aa6ww]
      #5723877 - 03/10/13 01:06 PM

OK, Ralph. And I didn't really write what I meant clearly. You would pan to the right but in the ep view, objects would appear to travel in from left to right (since it was upside down).

Edited by Special Ed (03/10/13 01:29 PM)


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RobK]
      #5723948 - 03/10/13 01:48 PM

Quote:

Yeah, sorry, these shots aren't the comet. The overwhelmingly bright part of PANSTARRS is the tiny, intense inner coma and if your images show just a tail it isn't the comet. Same for binocular & naked-eye views.

As the comet moves into darker skies over the next week, visually look for a faint 'star' to pop out, in the right position. The tail will reveal itself as the sky darkens. It is visible in binoculars before it is visible naked-eye of course - if you can locate the comet (think 'star'!) with binoculars then this significantly helps locate it naked eye.

It's still just visible from the south and a friend in NSW, Australia, successfully saw it again tonight. I haven't seen it since 6 March due to cloud. My "farewell" shot from that night is attached.

Good luck - hope it puts on a good show & I look forward to your reports & images!

Cheers -

Rob




That's a nice shot Rob. When I finally was able to detect it, it was just a few degrees off the horizon. Your description is perfect also. The comet does just kinda pop into view once it gets dark enough. Through a telescope, the view is pretty spectacular, the coma and wide tail are very detailed. I'll be using my larger 180mm F/6 refractor tonight since now I know how big it is and what I can expect to see.

..Ralph


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723956 - 03/10/13 01:53 PM

Quote:

OK, Ralph. And I didn't really write what I meant clearly. You would pan to the right but in the ep view, objects would appear to travel in from left to right (since it was upside down).




The straight thru views are kinda confussing. I have a nice William Optics 2" erect imaging diagonal, but when I use my widest eyepieces like my 41 Pan or my 31 nagler, it seems to vignette a little and with this comet, we need all the help we can get!

...Ralph


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Unknownastron
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5723974 - 03/10/13 02:00 PM

Jay, I must say I am on the fence regarding your "Panstarrs photo". It does look like a foreshortened contrail more than a comet as I can's see any brightening of a nucleus. However, it is overall the approximate size and brightness I expect for this comet. It also seems to have moved exactly as the comet would, just over 2-degrees in 9 minutes. I can not honestly say I thik it is or is not the comet. If clear tonight, I would go back to the exact spot with the exact rig and see what you can get.
It was absoloutely bad form to unfriend you and claim a falshood, as the worst you may have done is photograph something that looked a lot like the comet but was not. Anyone who has bgeen observing the sky for years will have a few erroneous observations under their belt. Even if it was not the comet you are the gentlemen and the astronomer here.
Clear skies and clean glass,
Mike


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RenoNV
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Special Ed]
      #5724001 - 03/10/13 02:11 PM

A group of four from Jack C Davis Observatory spotted 2011 L4 last night at Lake Tahoe, and a lot of the guesses above are wrong. First, the comet definitely had a bright nucleus. Second, your Starry Nights predictions are inaccurate, update the orbital parameters with JPL Horizons values and be sure that your altitude, latitude and longitude are GPS accurate. Third, it was rather visible in binoculars and larger telescopes would have been swamped (until the point that L4 set) by the sky brightness. Fourth, Mars was never visible (maybe hints of it), despite being brighter simply because the sky was too bright. Fortunately, the most eagle eyed member of the group refused to quit and Rick spotted the comet as we were packing up about 18:30 via his U-boat binos. It was never naked eye visible, and there were ALOT of contrails in the sky - which were getting blown all over.

Stay until dark! Don't give up, keep checking the horizon.

I watched the comet set behind the mountains on the western side of Tahoe thru 10x50s. No pictures, I didn't have enough faith to drag the extra weight along. Just 4 sets of binocular powered eyes, looking about an hour prior to perihelion. Several flashes were noted, but due to the Air Mass, we could not tell what the actual source for the flashes might have been. We used C2A for info, since it is easy to update the ephemeris, it plots trajectories and you can tune the field star brightness.


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Richard Low
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: RenoNV]
      #5724019 - 03/10/13 02:30 PM

The sky was terrible after the heavy downpour, so it was quite fortunate that Jiahao and I, together with the guys from NTU, managed to observe Comet Panstarrs on 10 Mar 2013 from about 7:30pm to 7:45pm (UT 11:30-11:45) at Nanyang Technological University (NTU), Singapore.

It was observed with the "Yellow Sub" 6 inch f/8 apo at about 30x with 40XW and the 10 inch dob.

I managed to capture a shot using EOS 6D with 400mm f/5.6, 1/8 sec, iso3200.



This cropped but otherwise unedited photo reflects quite closely what we saw in the 6" at 30x.


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Richard Low]
      #5724043 - 03/10/13 02:42 PM Attachment (54 downloads)

I love this hobby!!!!

My shots are either waaay too high or waaay too low to be viable. Incredible variance.

Okay, this little 14 year old friendless Facebook girl is gunna stir the pot with another dead horse COMTRAIL image.

A good conversation everybody! Thank you!

Jay

Edited by Jay (03/10/13 02:48 PM)


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the1andonlyfinn
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5724052 - 03/10/13 02:47 PM

Hoping to spot it here in SoCal tonight. I might just use my dob to sweep the horizon after sunset while the wife scans with binoculars. Took us some time to find an observing spot but looks like Palmdale Road runs due west/east with no mountains or hills for miles in either direction. Here's hoping!

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OleCuss
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: the1andonlyfinn]
      #5724183 - 03/10/13 04:14 PM

Jay:

I believe that you are posting straight and true. I've no doubt that your image is undoctored and that the phenomenon was present. I'm casting no doubts on your virtue or intellect.

But I don't think that was the comet. To me it looks to be too high in the sky for PanSTARRs at this time and I really don't see the coma.

I'd not fret about your reputation, I'd just try to be out there again tonight and take another shot at things. I'll be looking forward to your future product!


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Jon Isaacs
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: the1andonlyfinn]
      #5724217 - 03/10/13 04:28 PM Attachment (44 downloads)

My friend Kau and I spotted Panstarrs L4 last night (March 9th) from our "Havenly" Hideaway in Boulevard, California, we're about 5-6 miles from the US-Mexico border on the eastern slope of the Laguna mountains at about 3700 feet. It's a blue zone, the skies were very clear, right to the horizon which is about 3 degree elevation.

We had two scopes setup, my NP-101 and my ST-80 which is fitted with a 2 inch focuser, I was using the 31mm Nagler for a 6.0 degreee TFoV at 13x. I was focusing on the distant horizon which consists of brush and about a mile away. I was using Sky Safari Pro for altitude and azimuth data with a digital level to set the altitude, guessing on the azimuth.

I picked it up at less than 3 degrees above the horizon with the ST-80. It first looked like a star at in a fast Newtonian, quite bright but with a small tail. I was much smaller than we had expected but it was clearly a comet and in the few remaining moments (probably about 10 minutes before it set) we are able to locate it in the NP-101 and see the structure more clearly at about 34x as well as 10 x 50 binoculars.

It reminded me very much of watching Comet Holmes several years ago as it set across the desert.

Don't give up.

Jon


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Octans
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: OleCuss]
      #5724252 - 03/10/13 04:40 PM

Quote:

I really don't see the coma.




I think what he's trying to point out with that last image is that the "line" that looks like the tail is the coma -- just blurred because of Earth's rotation and the too-long 20 second exposure. With the comet being near the celestial equator, that "line" should be about 20 seconds of RA = about 5 arcminutes in length. At that scale, the comet seems to be a reasonable height above the horizon.

Edited by Octans (03/10/13 04:45 PM)


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aa6ww
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jon Isaacs]
      #5724257 - 03/10/13 04:44 PM

Quote:

My friend Kau and I spotted Panstarrs L4 last night (March 9th) from our "Havenly" Hideaway in Boulevard, California, we're about 5-6 miles from the US-Mexico border on the eastern slope of the Laguna mountains at about 3700 feet. It's a blue zone, the skies were very clear, right to the horizon which is about 3 degree elevation.

We had two scopes setup, my NP-101 and my ST-80 which is fitted with a 2 inch focuser, I was using the 31mm Nagler for a 6.0 degreee TFoV at 13x. I was focusing on the distant horizon which consists of brush and about a mile away. I was using Sky Safari Pro for altitude and azimuth data with a digital level to set the altitude, guessing on the azimuth.

I picked it up at less than 3 degrees above the horizon with the ST-80. It first looked like a star at in a fast Newtonian, quite bright but with a small tail. I was much smaller than we had expected but it was clearly a comet and in the few remaining moments (probably about 10 minutes before it set) we are able to locate it in the NP-101 and see the structure more clearly at about 34x as well as 10 x 50 binoculars.

It reminded me very much of watching Comet Holmes several years ago as it set across the desert.

Don't give up.

Jon




This is awesome Jon, you posted almost exactly the same thing I saw with about the same description and about the same remaining time before it slipped below the horizon.
Very cool and congratulations. More tonight, definitely!!

...Ralph


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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Octans]
      #5724337 - 03/10/13 05:19 PM

Quote:

Quote:

I really don't see the coma.




I think what he's trying to point out with that last image is that the "line" that looks like the tail is the coma -- just blurred because of Earth's rotation and the too-long 20 second exposure. With the comet being near the celestial equator, that "line" should be about 20 seconds of RA = about 5 arcminutes in length. At that scale, the comet seems to be a reasonable height above the horizon.




Thank you, yes! I see the drift direction, its length, the fact that it is the only such "cloud" anywhere in any of my images, headed very near the predicted path, or at least arguably in the general direction, of comet PanSTARRs... and of course, all the while, moving against a West to East jet stream, remarkably, toward the same horizon the sun sank behind.

Uncanny to me but I suppose stranger things have happened.

Jay


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Tonk
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5724368 - 03/10/13 05:37 PM

Quote:

I likewise wish you good fortune in your trek, Tonk.




Just back from my trip. Drove through blizzards there and back, but the destination up on the approach road to Kingsdale was clear skies to 1 degree above the sea horizon looking direct out to Barrow-in-Furness at sunset. That last degree was a band of clouds out over Northern Ireland

I can report that at 54N on the 10th March Pan-STARRS wasn't bright enough or high enough to break through atmospheric extinction over the Irish Sea. According to my data I had the following

18:04 - sun set at azimuth 265 - comet at azimuth 252
18:25 - sun alt -4 degrees - comet alt 5 degrees - azimuth 257
18:43 - sun alt -7 degrees - comet alt 2.5 degrees - azimuth 262
18:59 - comet set at azimuth 265

I was hoping to get a glimpse between 18:25 - 18:43 - no luck


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JMW
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5724373 - 03/10/13 05:40 PM

We had several scopes set up looking for the comet in the twilight. We were trying to observe Mar to get a position fix but couldn't see it in the bright twilight. My wife was the first to spot the comet in our TEC 140. A minute later it was observed in a C5 scope. We had about 8 people set it in one scope or the other. We had only about a 5-7 minute window after twilight faded enough before the comet dropped behind the low western mountains. A couple of us could detect a bit of the coma around the brighter center. We were fortunate to have wonder clear steady skies last night and had a fun time observing until we gave up do to the cold. Had a good time observing Saturn before we packed it in. Looking forward to Saturn getting higher earlier in the evening.

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Jay
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Re: Comet C/2011 L4 (PANSTARRS) new [Re: JMW]
      #5724528 - 03/10/13 07:11 PM

Hi all,

I had some interest in seeing my files so a sampling of Nikon RAW NEF images are now posted. You will need Photoshop CS5.5 or better to open them. They are large files -- 7360 × 4912 pixels:

http://www.admason.com/Astronomy/DSC_2503.NEF.zip
http://www.admason.com/Astronomy/DSC_2503.psd.zip
http://www.admason.com/Astronomy/DSC_2600.NEF.zip
http://www.admason.com/Astronomy/DSC_2604.NEF.zip *Used for inverted COMTRAIL
http://www.admason.com/Astronomy/DSC_2606.NEF.zip
http://www.admason.com/Astronomy/DSC_2611.NEF.zip
http://www.admason.com/Astronomy/DSC_2613.NEF.zip *Used for the Pleiades

Thanks!

Jay


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drbyyz
sage
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Reged: 11/04/12

Re: Comet C/2011 L4 (PANSTARRS) new [Re: Jay]
      #5724678 - 03/10/13 08:16 PM

Saw it in my 15x70s at roughly 8pm from outside charleston, sc. Light clouds on the horizon but a bit of the tail was visible, less than half a degree long by my poor estimating skills. It was roughly 5 degrees above the horizon and I would bet naked eye if not for the clouds.

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peteryan
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Reged: 05/17/07

Loc: SE Alabama
Re: Comet C/2011 L4 (PANSTARRS) new [Re: drbyyz]
      #5724741 - 03/10/13 08:52 PM

I caught it this evening at 7:14 CDT here is SE Alabama. I had almost given up when I saw it in 7X50 binos; not visible to naked eye. Very hazy,smoky, dusty on horizon when it finally revealed itself. Bright nucleus. curved, fan shaped tail maybe half a degree spread. After about ten min, was lost in obscuration. As a total noob I was enchanted!
Pete


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Ben B
member


Reged: 02/03/13

Loc: GA
Re: Comet C/2011 L4 (PANSTARRS) new [Re: peteryan]
      #5724785 - 03/10/13 09:27 PM Attachment (45 downloads)

I believe I finally caught it tonight at 8:29 EDT in western Georgia. It was perhaps 4 degrees above the horizon when I first caught it in binoculars and managed to barely get a picture of it before dropping below the clouds. There was definitely a fuzzy coma visible through binoculars with just a hint of a tail, probably due to how low it was when I caught it.

Attached is a picture - it's quite a wide field, but in the very center of the image you can barely see the fuzzy coma right above the line of dark clouds.


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peteryan
member


Reged: 05/17/07

Loc: SE Alabama
Re: Comet C/2011 L4 (PANSTARRS) new [Re: Ben B]
      #5724842 - 03/10/13 10:27 PM

Good job Ben! Couldn't get an image from my location.
What camera/lens/exposure?
Pete


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hottr6
Carpal Tunnel
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Reged: 06/28/09

Loc: 7,500', Magdalena Mtns, NM
Re: Comet C/2011 L4 (PANSTARRS) new [Re: peteryan]
      #5724887 - 03/10/13 10:53 PM

I saw it tonight before it set behind the western canyon wall at 1951 MDT. I saw it easily with 7x35 binos, but not with the naked eye. The head was quite visible, but the fanned tail was very faint, extending maybe 0.5-1 degree. More would be visible in a darker sky.

Shane in gray-zone NM

Edited by hottr6 (03/10/13 11:37 PM)


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Edward E
scholastic sledgehammer
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Reged: 03/26/06

Loc: Tucson, Arizona
Re: Comet C/2011 L4 (PANSTARRS) new [Re: droid]
      #5724939 - 03/10/13 11:30 PM Attachment (23 downloads)

A winter storm cleared out the skies Saturday and the sunset tonight was picture perfect so the comet hunt was on. I spotted the comet @ 02:10 UT ~ 6 degrees above the Tucson Mts. with a 9X50 spotter scope. I was never able to see the comet with just my eyes. I was able to get a few good photos of the comet as it set behind the Mts. Here is one made @ 02:17 UT with a Canon Power Shot SX220i set @ 400 iso, f5.6, 1.7X zoom, 2 second exposure:

Edited by Edward E (03/11/13 01:40 AM)


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BillFerris
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Reged: 07/17/04

Loc: Flagstaff, Arizona, USA
Re: Comet C/2011 L4 (PANSTARRS) new [Re: hottr6]
      #5724955 - 03/10/13 11:40 PM

Enjoyed observing Comet PanSTARRS for about 20 minutes, tonight. Here are a couple of images.






Both images are crops from the same 4288 x 2848 original, which was taken at 7:15 PM MST about a half-mile from my home in Flagstaff, Arizona. The original was taken with a Nikon D90, 300mm (effective focal length, 450mm) f/5.6, ISO 200, 2.5 second exposure. - Bill in Flag


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Ben B
member


Reged: 02/03/13

Loc: GA
Re: Comet C/2011 L4 (PANSTARRS) new [Re: peteryan]
      #5724956 - 03/10/13 11:40 PM

Quote:

Good job Ben! Couldn't get an image from my location.
What camera/lens/exposure?
Pete




Thanks! The image was taken with a Sony RX100 (high end point-and-shoot) at 37.1mm, ISO 200, 3.2 seconds @ f / 4.9. The image is cropped to about half its actual field of view and size reduced for display on here. There's a higher resolution version of the same crop at http://www.flickr.com/photos/benbrowning/8546160055/sizes/k/in/set-7215763293...

The comet had more structure visible in binoculars than what shows up in the image. I didn't have enough time to dial-in focus and tweak other settings before it dropped below the clouds.


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Edward E
scholastic sledgehammer
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Reged: 03/26/06

Loc: Tucson, Arizona
Re: Comet C/2011 L4 (PANSTARRS) new [Re: Edward E]
      #5724964 - 03/10/13 11:45 PM Attachment (66 downloads)

Another with a 3 second exposure:

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saguaro
member


Reged: 04/19/12

Loc: Southern Arizona
Re: Comet C/2011 L4 (PANSTARRS) new [Re: Edward E]
      #5724974 - 03/10/13 11:52 PM

Edward,

I spotted the comet setting over the Tucson Mountains at 7:11 pm, just a minute after your sighting! Easily seen in 7x50 binoculars but not with the naked eye. Tracked it in my 8-inch SCT until it disappeared in the horizon haze at 7:32 pm.

-Robin in Tucson (near Saguaro Natl Park West)


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Comet C/2011 L4 (PANSTARRS) new [Re: saguaro]
      #5724988 - 03/11/13 12:14 AM

I saw it again tonight from my urban driveway. Picked it up in an Orion 100mm r/6 at 37.5x about 6 degrees elevation. I point the scope with a digital level and Sky Safari, the deviation between the two was 0.1 degree... Small tail. Visible in 11 x 80s and 10 x 42s.

Jon


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Jay
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Reged: 09/01/06

Loc: Southern California
Re: Comet C/2011 L4 (PANSTARRS) new [Re: Unknownastron]
      #5724991 - 03/11/13 12:15 AM Attachment (75 downloads)

Hi all!

Fun night and good news. My COMTRAIL PanSTARRs was back again today. Brighter, and higher than yesterday and right in the area predicted by Starry Night Pro (just like yesterday March 9, 2013)

Thank you to those of you that gave me the benefit of the doubt yesterday. Unkownastron, I hope this gets you off the fence and at least put me in the plausible column.

Attached is a 20 second exposure with a 135mm lens.

Jay

Edited by Jay (03/11/13 12:22 AM)


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