I tried for Comet Asassn and even with 60 subs, I did not get much. The Canon 200mm F/2.8 lens was just too small of an image scale to do it justice. Bortle Red Zone conditions did not help. Plus, the parking lot lights from the nearby theater were still on for most of the imaging session. When they go off at 2:30 am, I can see about a mag to a mag and a half dimmer stars in the sky. I can do 5 minutes exposure instead of just 3 with them off and it makes a difference in the final outcome.