Secrets of Success

Don't be afraid to experiment. Try a variety of exposure settings (a technique known as "bracketing"), and keep a record to help you determine the best combination of film or ISO rating, exposure time, and f/stop for your particular site.

Unlike shooting through a telescope, focusing a camera lens is usually easy — just turn the focus ring to the infinity setting. But many autofocus lenses can actually focus past infinity. Determining the lens's sharpest focus may be a trial-and-error process, involving shooting several frames at different focus settings. The instant feedback of digital cameras makes it easy to find the best focus, and it's worth taking the time to do so. I've found that even a slight shift of focus, by no more than the width of an index mark, can make the difference between stars appearing as pinpoints or as fuzzy blobs.

A lens aimed skyward for extended periods will likely have dew or frost form on its front surface. At home I use a small hair dryer to warm the lens and telescope. At remote sites, a 12-volt heater coil wrapped around the lens barrel (be careful it doesn't turn the focus or f/stop ring) provides enough constant warmth to ward off dew.

An open shutter seems to attract aircraft! Always have a dark cloth or opaque card handy to quickly cover the camera lens until the intruder flies away.

On warm summer nights you might find yourself shooting through a flickering swarm of fireflies. On cold nights batteries can lose power, shutting down your camera or telescope drive. Then there are the plain dumb mistakes, like tripping on the tripod leg, shooting the whole night with the lens stopped down to f/16, or shining a flashlight onto a lens to check for dew, only to realize in your late-night daze that the shutter is still open!

Don't get discouraged — getting it all right is part of the satisfaction of taking souvenir images of the night sky. Just beware: astrophotography can be addictive. But it can also be immensely rewarding.