All,
I tried the North American Nebula last night, or that region, anyway, and found after stacking this morning that I (again) had sensor dust:
NAN - Album on Imgur
Does anyone else run across this when leaving the shutter open for 1.5 mins at a time or so? Do you just peremptorily clean it, or do you run a test image?
BTW, I used a 60-300 Adaptall-2 for this, and found the images to be better than the Vivitar 200mm.
