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A Comet as a challenge for beginners.

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#1 CosmoSat

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Posted 21 December 2012 - 04:55 PM

Observed this comet C/2012 K5 Linear a few days ago and the second withing the past 2 months(the first being Comet 168P/Hergenrother). Its a fairly bright telescopic comet at around mag9 now and supposed to brighten up to about mag8 by months end and is visible in the pre dawn skies. Only the core and coma is bright and its elongated shape is visible. Dont expect to see a long tail or anything.

I thought this might be an interesting additional object for many beginners who have been reporting their first views of DSO's here and almost everybody seems to hve decent sized equipment at hand.

Over the next few days the comet will be at a close proximity to Dubhe (Alpha Ursae Majoris) and should make for a easy hop. I hve attached a star chart to give an idea where the object will be for a couple of weeks or so. all positions marked are 00.00 Hrs UT.

Clear Skies!

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#2 nploop102

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Posted 21 December 2012 - 05:00 PM

whoa....I gotta try this.

#3 Fuzzyguy

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Posted 21 December 2012 - 05:14 PM

Thanks Sat, I'll put this on my list! I also followed 168P last summer. It was fast enough you could see that it was moving in relation to stars in the background if you watched for 30 minutes or so. This one looks like it's moving even faster!

#4 Doc Bob

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Posted 21 December 2012 - 05:14 PM

Thanks Sat!
I convinced myself to purchase a "comet filter" a couple of years ago . . . never used it, but this might be the time to try it out!!

Good viewing,
Bob

#5 CosmoSat

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Posted 21 December 2012 - 05:36 PM

@ nploop102,
I am sure u will find it an easy target with Dubhe as the starting point, use a low power eyepiece to start with.

@ Larry,
Yes its moving pretty fast, for those observing in the eastern countries right now will see it move across from east to the west of the star its close to as seen in the attached pic.

@ Bob,
Never used a comet filter yet( or know how they function) so would like to know how the comet looks like with and without it. Hope u get to see some traces of the tail too!

Here's a map for the weekend with stars down to mag 9.5 before the moon sets in next week.

Clear Skies!

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#6 CosmoSat

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Posted 23 December 2012 - 12:24 AM

Observed it again tonight, very easy to locate with dubhe in the same field of view. The tail is seen easily now. One can easily tell its a comet by its fan shape when compared with the galaxies in that region. Not as bright as M81 nearby tho larger in size.

Clear Skies!

#7 BrooksObs

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Posted 23 December 2012 - 12:50 AM

CosmoSat - A quality C2-type (Swanband) comet filter can prove quite helpful in a number of ways. In looking through one if it causes the comet's image to appear somewhat brighter this implies high gas production, or dominance. Conversely, if the comet appears to grow fainter looking through the filter, the comet is a "dusty" one. By the same token, the filter can identify the general nature of the different tails in regard to their dominant partical content.

And finally, these filters can prove useful in substantially suppressing the brightness of a twilight sky when trying to pick out a comet as it first is emerging from the solar region on the sky. This aspect should prove very helpful with comets PANSTARRS and ISON in 2013.

BrooksObs

#8 David Knisely

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Posted 23 December 2012 - 01:10 AM

Cosmosat wrote:

@ Bob,
Never used a comet filter yet( or know how they function) so would like to know how the comet looks like with and without it. Hope u get to see some traces of the tail too!


The comet filters block a lot of light except for the 5007 Oxygen III emission line and the bands of emission from certain comets in the Swan Bands wavelengths of molecular carbon (C2) and Cyanogen (CH). Not all comets have large amounts of emission, so the results with the comet filters will vary somewhat between comets. The old Lumicon Comet filter had a single passband for this similar to their standard UHC nebula filter but shifted somewhat in center wavelength. It tended to help a little bit more on those comets that have a lot of swan band emission, but again, these broader filters may not exactly make a huge difference in the contrast of the view. So much of the light from a comet comes from scattered or reflected sunlight that a filter may tend to make them somewhat dimmer, although they will notch out the airglow emission and some light pollution emission lines. For recommendations, either the Orion Skyglow LPR filter or the Lumicon Deep-sky filter would be good choices in broad-band filters if you don't want to get a regular comet filter. Clear skies to you.

#9 BrooksObs

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Posted 23 December 2012 - 09:45 AM

Elaborating just a bit further on the virtues of quality comet filters, specifically the one offered by Lumicon, they offer considerably more potential advantages in the hands of someone at least moderately familiar with comets and their physical make-up than may initially meet the eye.

Not only do they allow one to define whether the comet's main outgasing products are predominately gas, or dust, but they will often bring out very subtle internal features and details that are otherwise overwhelmed by the coma's overall brightness.

Often a comet filter will reveal individual filamentary streams of inoized gas leaving the inner coma and extending in a directly anti-solar direction perhaps otherwise hidden within the general glow of the inner tail (often composed of a combination of gas and dust). Likewise, dust features like the jets, arcs and related feature such as were visible in comets Bennett, West, Halley, et al. can become apparent in dusty comets by virtue of the dimming/suppression of the overall brightness of the coma is lowered.

And as I've already pointed out, these filters can be of considerable assistance in first detecting very bright comets situated against a highly luminous sky immediate after sunset, or just before sunrise. The suppression of much of the background sky's brightness can render visible a potentially spectacular object that would otherwise be lost in the brilliant light of twilight to other observers for days yet to come.

Among serious comet observers quality comet filters, such as the Lumicon product, are often taken to be an essential standard accessory.

BrooksObs

#10 wky46

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Posted 23 December 2012 - 10:26 AM

Not supposed to clear up here for a while but will definately give it a go once it does (maybe the moon will have waned sufficiantly by then). And having these wonderful maps you posted will definately give me incentive to try. Thanks CosmoSat

#11 nploop102

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Posted 23 December 2012 - 10:40 AM

@ nploop102,
I am sure u will find it an easy target with Dubhe as the starting point, use a low power eyepiece to start with.


Ha! You flatter me with your confidence in my absolute beginner skills. Unfortunately, forecast calls for clouds over the next few evenings.

#12 Seldom

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Posted 23 December 2012 - 11:34 AM

Saw it the other evening, around 9PM MST. It was pretty dim with the moon, but viewable. Would be better at dawn.

#13 CosmoSat

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Posted 23 December 2012 - 04:30 PM

Hi BrooksObs,

Thats some neat and convincing piece of information u hve posted on the advantages of using a comet filter. I had never really given a thought of using filters for any of the objects...solar system or dso's (other than the sun ofcourse). But as I was reading ur post...was already forming mental images (tho a bit exaggerated i know :p ) of how a comet would look like in the twilight sky through the telescope using one of these! I guess i would consider one in the near future.. tho would like to try before getting one.
Thanks a lot!

Clear Skies!

#14 CosmoSat

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Posted 23 December 2012 - 04:30 PM

Hi David,

A fellow amateur i know has one of the orion light pollution filters tho never used it. Will give it a try one of these days. And now i know will be reading more about the comets ..their composition..the emission lines and all that..
Thank You too!

Clear Skies!

#15 CosmoSat

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Posted 23 December 2012 - 04:37 PM

Hello wky46,

The next few days should be good really after the moon has set in the pre dawn sky. Hopefully the weather turns good for u.

Clear Skies!

#16 CosmoSat

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Posted 23 December 2012 - 04:52 PM

Hi nploop102,

Try observing it around midnight or later when its close to the meridian to get the best views..and yes..after the moon has set and u will sure find it. This past weekend would hve been good really as its close proximity to Dubhe would hve made it an easy target for u. I saw it last night with Dubhe in the same field of view of the eyepiece. Goodluck to u.

Clear Skies!

#17 CosmoSat

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Posted 23 December 2012 - 05:00 PM

Hi Seldom,

We couldnt detect it at all last night when the moon was up in the sky and the comet about 30 degree altitude rising in the NE. Saw it as a faint nebulousity when the moon was very low and about to set on the western horizon. After the moon set..it suddenly appeared bright..hint of a tail n all!

Clear Skies!

#18 Seldom

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Posted 23 December 2012 - 06:29 PM

Looks like it should be viewable for an hour or two before the moon by the New Year. Will it be getting brighter, or dimmer?

#19 darthwyll

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Posted 23 December 2012 - 09:49 PM

I got it! I'm very new to astrophotography but I was able to get at least some data. Still learning.


https://www.dropbox....12 K5 Label.jpg

#20 XwarpfactorX

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Posted 24 December 2012 - 01:59 AM

I went out and viewed it last night, and was even able to snap a quick photo. K5 is the third comet I've seen total, and the second I've seen through a scope.

http://i1217.photobu...EAR_23DEC12_...

I believe it is supposed to brighten by a few tenths of a magnitude over the next few days.

#21 stargazer424

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Posted 26 December 2012 - 10:07 AM

WOW! I didn't know there were any visible comets to target! If I can get out, I'll have to see if I can track it down...

I assume an 8" dob will have enough light gathering to pick it up, if I can get it in view?

#22 Kevdog

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Posted 26 December 2012 - 01:39 PM

If I get a good night, will have to try this. My C11 should show it much better than my LT8 did!

If you are not a star hopper, but have Goto then you can lookup the RA and Dec from PlanetDroid on android, enter it as a user object in your mount, then slew to it. (Note, you do have to look it up this way just before you view as it does move quickly).

That's how I found 168P a few months ago.

I never got a chance, but I was going to download the ephemeris from Meade and load it onto my telescope. Haven't yet had time to figure out how to do that for my Celestron yet (and don't have the connection cable yet). But that way the telescope always knows where it is.

#23 CosmoSat

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Posted 26 December 2012 - 01:44 PM

As of the now comet is about 8 mag and can easily be seen in a 8" scope. Tho it might be difficult to view it the next few days with the moon in the sky almost throughout the night. After 30th the comet will be favorably placed for observation before the moon rises and can be viewed after around 8pm in the evening. I hve attached a map but note the time is + 5.5 ahead of UT for each new day marked.

Clear Skies!

Attached Files



#24 Dennis_S253

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Posted 26 December 2012 - 07:10 PM

thans for the heads up. I just downloaded it in Stellarium. Your charts look right on. Maybe it will clear in the next couple nights.

#25 nploop102

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Posted 27 December 2012 - 10:43 PM

C'mon clear skies....

forecast doesn't look good until after the New Year. bummer.






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