First of all, this is a stitched panorama shot. 24mm focal (39mm at 35mm equivalent) was about as wide as I could get with my gear. So I oriented my camera vertically and made a series of 6 shots. I opened the aperture up to the widest setting of 2.8 since light was scarce and being focused at infinity (manually) it made no significant impact on DoF. The shots were exposed for 30 seconds each. That also was the longest my camera could handle.
Now, after I stitched the shots together in PTGui some problems became apparent. The moon was way overexposed. Actually a friend of mine was specifically shooting the moon and he said 1/1000 was the right value to get the moon exposed correctly. In my situation in place of a moon I had a large white ball with halo and some lens flare as a side effect (just a few reddish blobs). Actually, my compliments to 24-70 f/2.8L lens - I dare not think what kind of flare my old Sigma 18-125 would produce. Also at 30" exposure the stars get blurred. The Earth rotates fast enough for the stars to travel about 8 pixels on my camera.
Now, here's what I've done. I've stamped out the moon completely with the surrounding sky, so now I had a moonless sky with plenty of stars. I then created a new layer and painted some new stars on top of old stars using the brush tool of three sizes. I actually made them red at first to tell them apart from original stars. Then I filtered out the original stars using dust&scratches (actually, I could have just stamped them out). Then I desaturated the new stars so they became grey, played with levels and opacity and voila - a totally new set of stars on the sky in correct astronomic locations only not blurred as the original ones. As for the moon - I got it off some astronomy site and just color corrected it and added some halo. I would have shot the moon myself, but it was about 5 days before full moon and I didn't like that
After that I removed stuff that was really unnecessary in that shot - like some electric wires and stray little trees on the snow.
Oh, and the shots were done high in the Carpathian mountains at about 2AM. We had snowstorms for a few days and then suddenly the clouds disappeared and the sky was totally clear. We started shooting because we thought we'd not get another chance. We were wrong, fortunately, so later I'll show some day shots with lots of sunlight.
