The first time I looked at the sketches I was thinking that the filter made the nebula worse - then I adjusted the viewing angle of my screen and suddenly I could see what you meant. Interesting observation and the issue with the screen has made me think (somewhat laterally) about when I view through a scope: to stop being so impatient and to try the usual observing tricks, adjust my view etc. As always - a gratefully received blog entry - I tend to look at planets and doubles but (if the clouds ever clear [blah blah]) then it looks like I may go DSO hunting for a change. BTW: when's the book coming out?