Demon Science

Astronomy photography is a balance of exposure times, iso and patience. The lower your ISO the longer your exposure will have to be for the light particles to reach your sensor. If you kick up your ISO, which you can think of as the sensitivity of your sensor, you can capture more stars in a shorter amount of time. You'll also want to open up your aperture more to allow more light to pass through the lens. The lower the aperture number the more light can enter. Now you'll want to do this in manual mode, normally the M selection on the wheel. There you can manipulate all your settings. Of course you'll want to use a tripod to steady the shot in longer exposures. The best way, in my humble opinion, is to use an ISO around 100, 200, or 400. This will present less digital noise in your photographs. With the lower ISO you'll need longer exposure times. The exposure is indicated by a fraction (1/60 = 1/60th of a second.) You'll want to start around 15 seconds, which is usually indicated by a solitary "15" displayed. Then move up to "30." With most digital cameras 30 is the longest automatic setting, the next would be "bulb" which exposes as long as your finger is pressing the button, unless you have a remote of sorts which would making your life easier. I find it helpful to have a watch with a second hand and indiglo illumination. From there you can count 45sec, 1min, 1:15 and so on until you get the desired amount of stars glimmering in your image. The longer your image the more you'll want to close down on your apertureavoid over-exposing your image. But keep in mind that when you're doing long exposures the stars will be moving. So after a while they'll start to streak which can be fun for some people but a pain if you're just trying to get a crisp display of our galactic majesty above. You can also get a better image using a variety of filters which I haven't the financial means with which I can experiment. The important thing is to keep trying different combination until you find the images that look great to you. Remember that it requires a lot of juice for longer exposures and that means you'll need extra batteries-especially if you're stopping to look at every picture you take. Also with digital and higher ISOs what looks great in the little display may look atrocious enlarged. So keep your focus set to infinity, be prepared to spend a good handful of hours (bring beer!) trying out some new techniques. OH! Also, if you're setting up for long exposures there's a good chance you will return to find your camera covered in dew. You can combat this with an electric fan. So good luck and happy shooting!