Just some star trail images from a few nights out with Chris Allington, Tyler Burg and Evan Ludes. Pretty much each night was cold as hell. We were timing the near full moon on some of them so the snow would be lit up more, as well as any objects. Pretty much each time the settings used were F4, 400 ISO, for 30 seconds, shot in JPG. Then stack them later in photoshop or a stacking program. I think I had white balance set to tungsten to get rid of any of those casts.
This was about 4.5 hours long, but at 2 hours in frost started to move around the lens and cover it. This was just east of Blair, only 15 miles or so north of Omaha. This was not at all removed from light pollution really. None of them were except maybe the ones at the bottom from Murray Hill. A big bright moon was also out, not helping(yet purposely desired for snow light). Using 400 ISO helps pop out the stars. Since you are stacking a bunch of shorter 30 second shots, there just isn't any big light build up.
On these first couple the tripod was slowly moving as it adjusted to the bitter air, around 0F. It only shows up on the shorter star trails and anything not moving like a street light. You can correct it with the foreground stuff by just masking in one single frame/shot. Frost covered the lens again after about an hour and a half on this one. The strap, tripod legs, and camera body seriously looked like they'd been snowed on, there was so much frost covering everything. I'm doing this with the 5D II I just got lol. Cameras are to be used, not babied...I figure.
Again on this one I had some slow camera movement issues as things slowly adjusted to the real cold air. Maybe there was some lens creep going on too. What I don't get is why it looked like there were two of things like the telephone poles. I tried to thumb through the frames one by one but wasn't seeing where it jumped. Thing is with the moon moving it can affect shadows obviously. Like the shingles on that barn get real soft looking when you stack them all since their shadows are moving. I wonder if that is what made the two poles and double edge to the barn, that and there was some fog trying to move around. So seems there might have been a faint shadow on fog doing that. I don't know, I again tried to mask in one frame of the foreground stuff. The shot was also obviously started in late twilight to get some of the sunset colors. The stars are stacked with the lighten mode on a layer in photoshop. So anything light(a star) will show through, letting you stack them all with many exposures. I made a bunch of shadow people standing out there, by standing in one spot for about 30 seconds then movin to another location and standing there again, over and over. When I stack though, those don't show through because you are using lighten and they are darker. So if I want them to show up I have to do them all together themselves using darken. I then stack that on this one and use screen. I probably like it better without them.
Another cold night, this time we were doing river steam and hoping for light pillars, which we got big time later on(other account). Cool thing about doing 30 second shots and stacking for star trails is you can also use those for a time lapse video if you want. It looks kind of cool with this river stuff.
Same night but looking north up the river. Steam swamped us out soon after the end of these shots. It's too light over too big of an area to use the other star trail shots after it. It just covers up the stars if you include those.
Chris and I tried Murray Hill for low fog, lit by the moon with star trails(note fog up into hills left edge....cool time lapse stuff again from the trail exposures). Yet again cold as hell. We stood on that hill pretty much the entire night through the sunrise. Took a couple warm up trips down to the cars, but those just seem to make it worse when you go back out. Like you just get colder quicker after you do those. It was between 0-10F for that whole night. You can get real sick of the cold doing this lol. You also get really chapped.
I have other images from this in an account for the fog, without star trails.
Here is one later in the year. This was actually done at F4 with 3200 ISO 30 second exposure stacked.