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Tonk
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Reged: 08/19/04

Loc: Leeds, UK, 54N
Re: Comet C/2011 L4 (PANSTARRS) [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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azure1961p
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Re: Comet C/2011 L4 (PANSTARRS) [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) [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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Reged: 02/03/13

Loc: GA
Re: Comet C/2011 L4 (PANSTARRS) [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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Reged: 12/08/12

Re: Comet C/2011 L4 (PANSTARRS) [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) [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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Reged: 03/27/10

Re: Comet C/2011 L4 (PANSTARRS) [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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Loc: Leeds, UK, 54N
Re: Comet C/2011 L4 (PANSTARRS) [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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tezster
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Re: Comet C/2011 L4 (PANSTARRS) [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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Reged: 10/23/11

Loc: Sacramento, Calif.
Re: Comet C/2011 L4 (PANSTARRS) [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) [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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nirvanix
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Reged: 06/07/07

Loc: Saskatoon, SK
Re: Comet C/2011 L4 (PANSTARRS) [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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Reged: 02/03/13

Loc: GA
Re: Comet C/2011 L4 (PANSTARRS) [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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Phillip Creed
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Re: Comet C/2011 L4 (PANSTARRS) [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) [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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Special Ed
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Re: Comet C/2011 L4 (PANSTARRS) [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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Domerman
Just Lucky, I Guess.
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Re: Comet C/2011 L4 (PANSTARRS) [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
Markus
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Reged: 12/26/04

Re: Comet C/2011 L4 (PANSTARRS) [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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Reged: 10/23/11

Loc: Sacramento, Calif.
Re: Comet C/2011 L4 (PANSTARRS) [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
(38 34' N, 121 29' W)


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Yaar
sage


Reged: 02/18/09

Loc: 24.94N
Re: Comet C/2011 L4 (PANSTARRS) [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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