I was reading a blog page of someone who was experimenting with taking photos of star trails and I gave some advice. I decided to repost that advice here as other new photographers might find this useful to experiment with.
First of all, trails alone are a good exercise but of little photographic value because identical results can be produced with a software without having to be outside for a long time at night, especially a cold night. So, a very important element you want to add is a foreground or background subject, as in this two images of mine:
The first photo was a hour exposure with the moon rising. The moon gives enough light to expose the sage brush as well as the mountains.
You also want to be careful to exposing for too long with digital cameras, the sensor can over-heat resulting in burned pixels (those red and blue dots you get in an image) and that’s irreversible damage. Also, it’s preferable to use a full frame sensor camera, as well as a low ISO setting (I prefer 100) because less noise is introduced that way: the longer you expose, the more noise you will have. Ultimately, because of this problems, I think in this particular occasion film camera are still better than digital.
For the kayak I used the technique of light-painting, using a flashlight I lit up the boat so that it would expose properly. The white spot on the top right is a cloud moving. This night had a full moon, so I had to kill the shutter after less than 45 minutes so it woldn’t burn the image.