This is my first (well, actually second) attempt at star trails. As the earth rotates, stars seem to move and if you either expose long enough or take a number of pictures and blend them together you see these beautiful trails.
For this picture I did:
- Take 50 photographs (actually I took 53 but at number 50 I bumped into the tripod so I could not use the last three)
- Each with 20 seconds exposure (using a MIOPS trigger makes it easy. But any other timer will do as well). After each picture I give the camera 1s time for storage.
- 20mm lens
- ISO 100, f2.8
- Load all pictures into layers
- Set the layer blending modes to "lighten"
- If you took a dark frame at the end (picture with lens covered, same exposure time as the rest) you can also add it as a layer with mode "subtract". I took a dark frame but as it was completely black (no hot pixels) I did not use it.
- More exposures. I stopped at 50 because a) I was tired and b) I bumped into the tripod. Will be more careful next time.
- Try to have the polar star in the picture.
- Try different lenses. I have a 50mm prime, want to try this one.