Friday, July 4, 2008

Finding Things to See

I was at a star party one night, and the guy parked next to me had his wife with him, and a brand new telescope. He commented that he'd put out a lot to get the scope, and his wife was skeptical of the value of the money he'd spent. His telescope was a beautiful thing, a very nice size and well designed.

When it got dark, I could hear him struggling. It sounded like something was wrong with his guidance computer, or he had run into some snag with getting it started. It was obvious his wife was getting a bit impatient. My wife was busy looking at Saturn through my telescope, so I walked over and offered to give him a hand.

It turned out he hadn't charged the power pack for his telescope's computer and drive system. He hadn't realized he needed to charge it before using it, or had forgotten. He was about to pack it in, but I offered to point his scope at a few things for him. The fact is, I wanted to get a look through it. As I mentioned, it was a beautiful scope and except for the computer I was a bit envious.

He gave me the go-ahead, so I used the manual controls to put it on Saturn. Then I stood back and let him and his wife have a look. Saturn was crisp and clear, the rings were so sharp you could cut yourself on them. Saturn's moon Titan, and two others, probably Rhea and Iapetus, were on each side of the planet.

After everyone had gotten a good look, I moved on to a series of other showpiece objects in the sky--the Double Cluster, the Ring nebula, and so on. About 1am they were getting tired and decided to pack it in. His wife was in a really good mood, though. As they were packing up, I heard her tell him "That really is a nice telescope. I hope you can get the computer working so we can see that stuff all the time!"

The biggest hurdle to beginning telescope users is getting something interesting to see in the telescope. To do this, you need to know where to point a scope, you need to get it to point there, and it has to stay where you put it.

Where to Point the Telescope

Finding the Moon is easy. Finding bright stars isn't tough (and some of those bright stars may be planets!) Finding other things takes an extra step, but doesn't have to be tough.

Get a book that gently and easily teaches you to find your way around the sky. I highly recommend 365 Starry Nights by Chet Raymo. There are other good books, too, I'll post some reviews later.

Even if you've got a computer on your scope, you'll need to know a few of the bright stars by name. There are different ones up in different seasons. You'll also want to learn at least a few of the easy constellations.

You already have a head start on this. You can probably already find Orion and at least one other constellation (like the Big Dipper if you're in the northern hemisphere--close enough for Ursa Major.) Picking up one or two more will be easy.

Pointing the Telescope

You need a finder that works. Those silly things that look like little telescopes on the side of your telescope don't work. You need a "reflex sight." This is a finder that doesn't magnify the sky, it shows a red dot or red rings on the sky. You look through it and move the scope until the red dot or center ring is on what you want to look at (or use to line up your computer.)

I recommend the Telrad. In my experience it's the best. There are some other good reflex sights out there, too. But get rid of that little telescope finder. Give it to a kid for a toy or something. Some telescopes come with a reflex sight now instead of the little finder scope. This is a plus, if nothing else it shows that the maker of the scope cares about people being able to actually use it.

The Telescope Stays Where You Put It

A mount has two jobs. Hold the scope up where you can look through it, and keep the telescope pointed at what you put it on. No matter how good your telescope is, if the mount doesn't do its jobs the telescope is useless. A so-so telescope on a good mount is worth far, far more than an excellent telescope on a bad or so-so mount.

I like Dobsonian telescopes for beginners. They are stable, easy to use, easy to set up, and they handle a lot of abuse and still work great. The telescopes I throw in my car week after week are Dobsonians.

But, Dobsonians don't have a computer to put them on things in the sky. They don't have a clock drive to keep them pointed at something as the Earth turns.

In spite of that my preference still comes down on the side of the Dobsonian. But a well-made telescope with a computer can work well, too. So long as it has a good mount.

A good mount doesn't let the telescope slowly slide down after you put it on something. It doesn't move the telescope when you lock it into position. It doesn't wobble. You can give the telescope a sharp rap and it will still show the object.

If you're trying a telescope out in a showroom, try to point it at something small and as far away as you can see (don't look toward the Sun, if it's visible!) Even if it's too close for the telescope to focus on it (like a book on the far wall of the store) you should be able to point the scope at it and lock the mount (if it's one that locks--most Dobsonians don't lock, and don't need to) and be able to see your object. It should stay there when you're not touching the scope. It should still be in if you tap the scope, either on top or the side.
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