Although it doesn't appear very obvious at this size, this is one of my carelessly focused subs mentioned on the previous post. I thought I would post it to show just how good the transparency can be on occasion even from a light polluted site. Unfortunately such conditions are a rare appearance. On most imaging sessions I'm usually wondering if there is any benefit going from 8 to 10 minute exposures. Revealing the improvement a good sky brings, this sub of M51 is a 15 minutes exposure and could probably have been 20 or more minutes to advantage. When compared to some of the examples of subs published on earlier posts my annoyance at not making the best of the conditions by taking more care with focus might be easier to understand.