Do you know the name of that chain of galaxies in your picture?
I believe it's a portion of Markarian's Chain.
Why are you using ISO 1600? Unless you are taking your images in pristine dark skies avoid using such a high ISO. An ISO of 400 will yield much less noise and won't wash out as quick.
Force of habit I guess. I'd been imaging with no guiding for several months, so I used the highest ISO to take the shortest exposures. I'm beginning to get the hang of auto-guiding, so I should be able to back off on the ISO. I'll try the 400 speed at my next opportunity (if we ever get clear skies in this part of western N.C. again!).
Thanks for the comment and suggestion.