Such events turn my attention to astrophotography. Some time ago, I told you how to , and I've also explained the basics of by using very long exposures. This week, I'll focus on shooting star trails by taking lots of relatively short exposures and then combining the results.

You have a lot of ways to capture the beauty of the night sky with a camera, but shooting star trails is among the easiest, mainly because you can do it with almost any camera. There's something magical about these kinds of photos, because they reveal the mathematical precision of the cosmos generally hidden from the naked eye--it's easy to see that the earth spins under a blanket of stationary stars.

Photo courtesy of Flickr user

To take a star-trail photo like this one, all you need is a camera with a manual exposure mode; such a camera will let you dial in the shutter speed and aperture setting independently. To make things easier, you'll want either a remote shutter release that you can lock (so that the camera takes photo after photo with no intervention from you) or an "intervalometer" mode, in which you can schedule the camera to take a set of photos automatically. Check your camera's menu or user guide to see whether it has such a mode.