Over the years I have had many comments on my star-trail photographs. I guess it's because it is not something that many photographers do and people are just not used to the effect.
Not really, all you really require is a camera that can use a cable release and a good steady tripod, and lots of patience.
I actually started doing them out of sheer boredom. A few years ago when I started doing a lot more late season camping up at Riding Mountain in September and early October, I discovered that there wasn't much to do up there once it got dark. Since it gets dark about 8 o'clock I would have a lot of time to kill until I went to bed.
One such night I thought I would give star-trails a try. I had never done any before but had seen a few in the photo magazines so I thought I would experiment with them. I used to hate the dark since I couldn't photograph, but since starting to do star-trails, I love it almost as much as daytime.
The real trick is to find something interesting to put in the photo to give it some perspective. The first attempt I made, I just pointed the camera straight up. The problem with this is while you do get the interesting streaks; you can't tell what they are without something in the photo to give it perspective. They could be headlights, or fireworks, or just about anything else.
My next attempts were quite a bit better as I started to include trees somewhere in the photograph. This gives the viewer the perspective to be able to recognize the streaks as being in the sky.
Now I have developed some favorite techniques. I love the effect of the star-trails reflecting off of water, such as a stream or lake. I like to add any tree(s) that have some character. I prefer to add coniferous trees if possible, usually a pine-tree bent over the water, or an old dead pine tree and have the streaks pass through the branches. I also like taking star-trails over the mountains whenever I'm in the Rockies.
All you do is set your camera up on your tripod, and using your cable release, with the camera on the B (bulb) setting, lock the shutter open. It is preferable to use a fast 1.4, 1.8, or 2.8 lens on the camera since it is very difficult to see anything in this low light. Though you aren't focusing much since the lens is set to infinity, you still have to be able to "frame" the photo properly. i.e. situate that pine tree properly.
The other experiment to make is deciding which stars to aim at. This will determine the direction of the streaks. Depending on what you aim at, the streaks will appear as an arc, or even a circular pattern. Now, I wouldn't consider myself to be even an amateur astronomer, but I believe it has something to do with the position of the north star, which I believe is situated close to the Big Dipper
(one of the few constellations that I can recognize).
I do know that if you include the Big Dipper in the photo you will get the circular pattern. It's pretty cool!
I use ISO 100 film since I prefer the fine grain. I usually stop the lens down to around 5.6 and use about a half- hour exposure. All of these can be up to you to experiment with, these are just my preferences. I used to use high speed film, but have found it unnecessary due to the long exposure times, and I don't like the look of the higher grain.
Please note. It really helps if you use a manual/mechanical camera, or, an electronic camera where the bulb setting is mechanical rather than electronically controlled due to the long exposure times. These long exposure times are very hard on the camera batteries, especially when it's cold out. This can get expensive.
At first I would use my 801 camera since it had the cable release capability, but I would kill the batteries very quickly. This would become even more costly since I was using the more expensive lithium batteries at the time.
I was lucky to pick up a cheap Nikon that a camera store wasn't going to bother to repair since the meter didn't work. To them, it wasn't worth repairing. Luckily, the shutter still worked on the mechanical bulb setting, so I now use this for star-trails.
One of the drawbacks of shooting star-trails is, due to the long exposures, you can't shoot very many on any given night. Also, since it should be perfectly clear on the night you are shooting, this limits the number of shooting opportunities. It can take quite a while to finish a roll strictly of star-trails.
I was again lucky to have a friend who used the same model of Manfrotto tripod as I did, but he decided to change brands. He was nice enough to give me his old gear since the tripod itself needed some repairs. I was able to make one good tripod out of the two, and as a bonus, I was able to use a Manfrotto accessory arm he had also given me. This accessory arm allows you to mount two tripod heads to the top of your tripod, and since I actually had two extra Manfrotto heads that I had purchased over the years, so now I can use two cameras at the same time for shooting star-trails.
My second star-trail camera actually came from my antique collection. I had picked up an old Exacta in mint shape years ago, so I decided to put this old German camera to use since I knew the optics would be quite good. Who cares if there wasn't a meter?
Now I use the dead Nikon usually with either the 24mm f2.8 or 50mm f1.8, and the Exacta with a 50mm f 2.8. Now I can shoot twice as many star-trails as before. It's nice to have the two different focal lengths for each shot, or a choice of vertical or horizontal, as they both will give different results.
Let me tell you, it's a whole different world out there once the sun goes down. One of the first things I noticed was the amount of air/space traffic. Planes, satellites, and meteors have all appeared in my star-trail photos, sometimes together. I have one shot in particular that has three planes and a satellite passing through.
You can tell airplanes by the flashing lights, which appear as dashes in the photo, white lights means the plane was approaching, red lights means the plane was moving away from you. A satellite appears as a straight white streak that crosses the entire frame, and meteors appear as a short white streak.