Another Go at M81 & M82

[Davide Simonetti]

I like returning to these targets regularly because on every attempt I manage to bring out a little more of M81 (which is absolutely vast and should fill nearly a quarter of the frame). I guess the trick is to keep adding more data. 

This image comprises of data from February 18th and March 25th 2015. 28 x 30 Second exposures at 3200 ISO plus 43 x 30 second exposures at 6400 ISO with 19 dark frames and 16 flat frames.

[graemlourens]

Hey Davide

Also one of my favorite targets up to now, difficult but not impossible ones with moderate equipment

I am a little surprised that there is no visibility of M81 arms. In your raw frames do you see detail of M81 that then got cut out when you darkened the image? (maybe you can post a unprocessed single image?)

Regards, Graem

[Davide Simonetti]

Hi Graeme, there isn't much more visible in the light frames but when I play with the image after Deep Sky Stacker has done its job, there is a faint lightening from the nucleus to where the edge of the Galaxy should be. Unfortunately it isn't quite enough for me to work with and I lose it when I darken the sky. Part of the problem is I live in a heavily light-polluted part of London. When I get to my computer later today I'll post a light frame (it'll probably have to be a shrink down JPEG version). Cheers.

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[Xplode]

Very good when thinking about the slow scope you are using

Your biggest problem isn't light pollution, but a scope that is really slooooooooooooowwwwww.

If you want better results there is no way around getting a scope with faster optics

[graemlourens]

Uhhh, i should have checked the scope jep f11.8 is very slow.

so then i'm very impressed how well M82 shows up !!

[kalasinman]

Hi David, I've been comparing sessions with 45sec exposures @iso640 with  1/4 the number of subs at 2 mins. @iso 1250, perhaps due to seeing on different nights, but I'm getting the idea that longer subs gives more faint detail. I think the biggest improvement would be an EQ mount, or move to Tibet.

[Davide Simonetti]

Hi David, I've been comparing sessions with 45sec exposures @iso640 with 1/4 the number of subs at 2 mins. @iso 1250, perhaps due to seeing on different nights, but I'm getting the idea that longer subs gives more faint detail. I think the biggest improvement would be an EQ mount, or move to Tibet.

An EQ mount would solve a few problems, at the moment I'm muddling along with the AltAz mount perched on a homemade wedge but even with as good a polar alignment as I can get, I still can't expose for longer than 30 seconds before stars start streaking. When finances allow I'd like to get a proper EQ mount and maybe a guide scope

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