Globular Cluster M13

Hello folks, despite all the bad weather, I have managed to get a shot of M13 with my new set up of my C80ED and CGE mount. Here is M13, shot with a Canon 40D, it's a stack of 36x90 second exposures UNGUIDED : cheer: plus 30 dark frames at ISO800, shot on November 29th last.

The air was very cold and dry that night with very strong moonlight. You can also see a little 11th magnitude galaxy at top right, a real first for me

www.webtreatz.com/gallery/displayimage.php?pos=-67

Thanks for looking ,

Keith.

My favourite DSO in the sky !!
Globulars are not imaged often enough IMHO.
Tough little targets they are, you got a nice one of this globular, even got a nice galaxy in there aswell !
thanks for putting it up.

Hi Keith - nicely framed and the colour is pleasing.

On my monitor the backround looks rather bright and there seems to be a little tracking error across the image with stars looking ever so slightly eggy. I thought at first it could be coma but on a closer view the egginess is across the image.

Was it maybe one or two iffy subs?

By the way, I hope you know that my critisism is constructive - my first M13 in comparison - well, let's say it just doesn't compare and I'd be embarrased to post it alongside yours

I'd love to see you give this another go - your composition is spot on. If you can nail the tracking and the background, hell, that's a nice wallpaper for me

Cheers
Dave

Hi lads, thanks for your comments. You've said it exactly as it is Dave, the stars are a little eggy, maybe it was one or two bad subs, I stack the best 90%, maybe I'll put that down to 80% so.

The background is a little light as there was some serious moonlight that night, it was very strong and no filters were used. I'd love to give it another go in the springtime, but I'm pleased with it since it's unguided. I don't expect wallpaper worthyness just yet, maybe with enough practice I'm still getting used to the CGE :silly:

Keith..

Nice!

I solved it with tycho2,ngc/ic - also note an ex supernova marked with an yellow cross by Asiago supernova catalogue(2009):

larryo.org/tmp/m13_solved.jpg

Larry

Larry

How happy are you with your plate solutions? - I only have screen shots of your application but I have a definite sense that the catalogue circles are systematicaly skewed to the bottom right of target stars.

When you perform a plate solution do you calculate what your residuals are?

A good plate solution would have residuals (given best eforts in timing and observer location etc) in the order of about 0.2" for an applciation to be useful (in my humble oppinion).

I'm new to astrometry - but I would want as best accuracy as I can attain - if I were to do this sort of stuff - which I might - one day.

BTW to Kieth G - good image of M13 - I tried it - don't think I was collimated or focus was out - these clusters are under estimated in terms of targeting. With these things its hard to get detail of features - they're so intricate. I liked your post - its a good stab - there is a bit of a trail - but its better than my only capture of this target.

Mark