Nice set of images there.
Regarding sky flats...you can go down the pain in the "A" route Jase has suggested with sky flats or just get one of these:
http://www.pbase.com/strongmanmike20...andy_lightring
Absolutely simple to use, repeatable and you don't need to be restricted to dusk or dawn, besides and as I often found, what if it gets cloudy before you can take your sky flats and you must dismantle your imaging settup? - can't get matching flats then huh?
Sky flats work well for a permanent setup where your equipment is left assembled the same way for extended periods, thenyou can get the matching falts another dawn or dusk.
Just my 2c worth
