M-81 nemesis

Hello All;

For the past couple of years I have been able to take some great galaxy and nebula shots with textbook style detail. I have been using an sbig 237 with an 11 inch f 4.5 dob on an equatorial platform. Two galaxies that seem to be my nemesis have been m-81 and m-31. The picture attached is a poor quality shot of m-81 (8 shots stacked at 65 seconds each for a total exposure time of 520 seconds or a little over 8 and a half minutes). The camera was at medium resolution and was -14 degrees at the time of the shots. This shot is very typical of what I get when taking M-81 or M-31. Do I need a longer exposure time? I tried stacking more images on top of this shot with less than pleasing results. Any input on how I can improve these results on these galaxies would be appreciated.

Thankyou

Attached Image:

m31 and m81 are tough galaxies--they have very bright cores and extremely dim outer regions. The key to viewing both is to use non-linear histogram adjustments and perhaps even some layer masking. Looks like you have a nasty lower right to upper left gradient and some vertical bands. Is the image dark/flat corrected? This usually takes care of most of the banding. Also, the gradient should be removed before making your histogram adjustments on the galaxy. More exposures NEVER hurts. My $0.02