[codemonkey (Lee)]

Thanks everyone!

I tried to shoot some flats last night figuring the scope hadn't been moved so I might be ok, unfortunately I ended up with a big dark patch in the flats that wasn't in the lights so they were unusable (maybe condensation?).

Either way, what I did notice was how nasty it was... the lights don't come close to telling the full story. I'll definitely be taking flats in future!

Originally Posted by RickS

I also recommend that you take flats but it's also a good idea to get rid of the dust from time to time. Here's a calculator that will help you figure out where you need to clean: http://www.wilmslowastro.com/software/formulae.htm#Dust

Cheers,
Rick.

That's a really cool link, thanks Rick! According to that, the dust should be on the glass covering the CCD sensor, which is interesting because I was pretty confident that it was on the filters.