C/2012 K1 PANSTARRS effort.

[JB80 (Jarrod)]

Here is my rough effort from last night. This is proving to be a tougher task than I originally hoped but mainly due to my wide field rustiness more than anything.
The first night I had 2 1/2 hours worth of subs with the comet bang in the middle tossed because it was out of focus. Last night my first mini sighting run was successful which is what this pic is from but it was only 7 and a half minutes worth. I then repositioned and shot for nearly 2 hours but somehow managed to miss the comet all together.
There was also hazy cloud which hasn't helped noise wise.

So basically it's all coming together to get a good run eventually as I wont make the same mistakes 3 times in a row, maybe.

Anyway this is seven and a half minutes of 30 second exposures with a 75-300mm zoom at 300mm, darks added, ISO 1600 on the Polarie.

Things to try the next chance I get are to up the exposures to a minute(not too taxing on the Polarie), much longer session, possibly try with the OIII filter? and centre the damn thing.

Overall I'm happy as it's the second real comet pic I have taken and it's certainly definable.

[cometcatcher (Kevin)]

That came out reasonably well. Good work.

Comets are fairly broadband in the spectrum even though they look green. There are specific "swan bands" to identify certain gasses - mostly greenish. Narrow filters like the OIII don't help much photographically. Lumicon used to make a swan band comet filter but it was for visual use. They recommend the deep sky filter for comet photography, if a filter is used at all.

[JB80 (Jarrod)]

Thanks Kevin.

I really want to give it a bit more time next time, I know my lens is not the best nor my processing but I'm reasonably sure just more time will be an improvement.

I only thought to try the OIII as it's already in the camera from the day's white light efforts. I'll take it out then.

[Rob_K]

Good job Jarrod, nice to see a DSLR/lens/Polarie shot that isn't a Milky Way widefield! There will be lots of comets within your reach. I've gone up to 3 mins at 200mm zoom with a Polarie so a minute shouldn't be any problem. Do you have the little 'telescope' accessory for accurate alignment?

Don't worry about filters - DSLRs pick up the nice green if it's a 'gassy' comet. People who do astrometry on comets often use R-band filters which pick up the dust reflections but miss out on the Swan band emissions which give the nice green extended comae. Visually, 'comet filters' provide greater contrast at the eyepiece to see faint gassy comae but photographically you might as well take all the light you can get. Keep up the good work!

Cheers -

[JB80 (Jarrod)]

Thanks Rob.

I try to vary it up when I can plus the MW isn't up yet in theses parts so that helps. I have had 300mm for 2 minutes, I wouldn't like to push it further than that.
Yep I have the polar scope for it and Polaris to help, makes it kind of easy.

Well I won't bother with the filter then if it's not needed, maybe on a non comet target but as you say the more light the merrier.