When it comes to backyard astronomy, some things are obvious, some are not. And if you’re just getting started, far more things fall into the latter category. Here are a few essential tips that will allow you to get up to speed quickly.
Seeing in the Dark
If you’ve been around other backyard astronomers, you’ve probably noticed their fondness for flashlights that produce a soft red light and wondered why. Your eyes can see better in dim light after they’ve had a little time to adapt to it. This ability, called dark adaptation, happens naturally, and the longer you avoid bright lights, the more sensitive your eyes become. So what do you do when you need to check your star charts or find a missing piece of gear? This is where the red light comes into play. Our dark adaptation is not adversely affected by dim red light, which makes it ideal for stargazing. Special red LED flashlights suitable for stargazing can be purchased from any telescope dealer, or you can convert a normal flashlight by simply covering its lens with red wrapping or kraft paper. Red cellophane also works, but it is not as easy to find and doesn’t dim the light as effectively.
Decoding Binocular Specs
Binocular specifications are easy to figure out. Have a look near the eyepieces for numbers like 8×40 or 7×50. The first number indicates the magnification, and the second number is the diameter of the objective lenses in millimetres. For example, 10×50 binoculars make objects appear 10 times closer and have front lenses 50 millimetres across. Experienced backyard astronomers prefer binoculars that magnify 7 to 10 times, with objective lenses between 30 and 60 millimetres. Why? Binoculars that magnify beyond 10 times have narrower fields of view and are more difficult to hold steady, making it harder to point them at a specific celestial target. And binoculars with main lenses larger than about 60 millimetres are too heavy to hold up to your eyes for more than a few seconds.
How Powerful Is It?
Most first-time telescope buyers assume that magnification is everything. It’s not. In fact, just about any telescope can be made to magnify any amount. Want 500×? No problem. Just insert the appropriate eyepiece (the interchangeable lens assembly you look through) into the telescope’s focuser, and voilà — power! You can calculate the magnification of a given setup by dividing the telescope’s focal length (found in the manual or printed on the scope itself) by the focal length of the eyepiece (stamped on the top or side of the barrel). For example, a 25mm eyepiece in a telescope with a 1,000mm focal length gives 40×. Want more power? Try a 10mm eyepiece for 100×, and so on. But before you go power crazy, beware of something often referred to as empty magnification. That’s when a telescope’s power is so great, the image becomes fuzzier and dimmer instead of more detailed. For most backyard telescopes, anything over 200×falls into this category. Even large scopes are rarely used above 300×. Experienced observers actually covet a telescope’s low-power capabilities much more. So when you see a small telescope in a brightly coloured box boldly proclaiming “600 power!” walk away. You’ll be glad you did.
Most people live in or near cities. That’s bad news for the astronomy aficionado. The problem is that the skies above major towns and cities are brightly illuminated by light shining into the sky from poorly designed outdoor lighting fixtures. This wasted light, known as light pollution, makes the gentle glow from distant stars and galaxies tough to see. If you want to view the universe in all its majesty, you have to get away from large urban centres and will need an easily transportable telescope.
Picturing the Universe
Seeing is believing, but sharing what you see can also be a rewarding and fun way to enjoy the sky show. Indeed, there are enthusiasts who get so wrapped up in photographing clusters and galaxies that they spend very little time actually looking at them. Although some sky photography can be done with fairly little effort, the detailed images of nebulas and planets you see in books and magazines demand a significant amount of dedication as well as specialized equipment. If you’re just trying to figure out what backyard astronomy is all about, save astrophotography for later. The stars and planets will still be there, and you’ll be in a better position to tackle it once you’ve spent a little time soaking up starlight yourself.