Practically all books, magazines, and web sites guiding you in the process of buying your first telescope tell you the following two things:
First, don't buy your telescope at a department store.
And secondly, go to a star party before you buy.
OK, that first one is pretty easy. But what about the second? Most of these guides make the implicit assumption that you know what to do once you've gone to the star party. While few of us interested in the night sky are likely to do nothing at the party, we might not make the best use of our time there. With that in mind, here are a few of my own thoughts about star parties, which you can and should combine with other people's thoughts.
First of all, most importantly, be courteous! These are club members, not employees, and they are volunteers. They are not required to show you what you want to see, but if you ask nicely and don't insist, they will generally accede. If you have children with you, you are responsible for them and their actions. Make sure they do not poke their fingers on any optical parts (lenses and mirrors) or risk tipping things over. If they or you do accidentally damage something, notify the owner. Do not attempt to fix the damage yourself; you may only make it worse. While you're waiting in line to try out a scope, don't stand idly—listen for what the owner says about what to do and not do when it's your turn. If you follow these simple rules and some common sense, most club members will be eager to show off their scopes.
The one major exception is someone who is doing astrophotography or CCD imaging. You must absolutely not interfere with the telescope setup in these cases. Don't look through their finder, don't touch the camera or the scope or the mount, don't look into the big end of the telescope. It sounds very blunt, but these people are here to demonstrate their photography set-up, and they quite rightly get upset when they can't show it off because someone has ruined their 30-minute exposure.
Now, down to the fun part of star parties—getting to try out all those different scopes!
What a lot of guides don't tell you is that going to a star party is as much about finding out about you as it is about finding out about the various brands and models of telescopes. If you've been eyeing that big Dobsonian or SCT, watch someone set one of these monsters up. Offer kindly (but do not insist!) to help them set up. Many people are willing and eager to have someone else carry their rocker box or tripod; it's the scope and mount they're leery of having in someone else's hands. Watch someone who knows what they're doing perform polar alignment. It's not necessarily difficult, but it's something you may have to do, depending on what kind of scope you purchase. If it's a GOTO scope, watch them do their initial two-star alignment—that's the process by which you "teach" the computer to locate objects in the sky.
On the other hand, perhaps you're attracted (as I am) to cute, little instruments. If you can, take a look through that 70 mm refractor or the 3.5-inch Maksutov-Cassegrain before buying it. They can offer delightful views of the planets, but you may find out you're more interested in deep sky observing, and while these smaller scopes aren't entirely useless for that purpose, there's no question that you'll be better served with something quite a bit larger, like a 6-inch or larger dob. The bigger scope will show you objects that can't be seen in the smaller ones, and even on those objects that both can see, the larger scope will show you more detail.
Once you've caught a glance of a favorite object in the sky, ask someone to point out where it is above you (if you don't already know where it is). Try to judge if you're the sort of person who would enjoy navigating the night sky on your own, or if you need the assistance of digital setting circles (DSCs) or GOTO. If you already have a pair of binoculars, make sure you bring those along. If you can find the object (or at least the location in the sky where it is) through the binoculars, you're probably well-suited to star-hopping. DSCs and GOTO (read an explanation of how they work) are useful and entertaining, but they do add to the cost of the telescope, so there's no question you can get more scope for your money if you can find your way by star-hopping.
Of course, it's not all about you—you should find out about the equipment too! After looking through a few scopes, you may have decided on which set of optics you like the best, but what about the steadiness of the view? That depends a lot on the quality of the mount and tripod, if any. When testing one out, it's a common tactic to rap the tripod and see how long it takes for the vibration to settle out. A couple of seconds is typical. If it takes 5 seconds or more, the mount/tripod is probably insufficiently strong or stable to support that particular scope.
Scope owners don't always take kindly to people rapping on their tripods, however, so here's an idea you might try—ask them where the focus knob is. Even if the image is perfectly in focus for you, try racking the focus in and out. Is it relatively easy to get the image to stop shaking enough for you to focus, or does it shake so much that you have to let go, wait for the image to steady, adjust the focus again, let it go, rinse, repeat? Keep in mind that you will get better at this, but it is a measure of the mount and tripod's stability.
Try looking through the finder. On some scopes, due to the design of the mount, the finder is so close to the tube, and in so awkward a position, that it's difficult to use. You may want to use a unit-power, red-dot finder (like a Telrad or similar device) instead; if there's one of those at the star party, you should find an opportunity to try it out. Owners of these unit-power finders tend to be strong proponents of their usability, especially for beginners, so most of them will be willing to let you take a peek.
If, by magical chance, you should find someone willing to actually let you move the scope from object to object, and you're not all thumbs, then by all means avail yourself of the opportunity! Let the scope owner teach you how to move the scope. Make sure that you don't force anything; many mounts have clamps and clutches that prevent the scope from slipping when the scope is fixed on an object, and you can damage the mount if you try to move it again without releasing these. Ask yourself if you find it reasonably easy to move the scope in the direction you want.
Lastly, if there is any chance of meeting up with these people again (let's say you're joining the local astronomy club), this is an excellent opportunity to form new connections. If you've narrowed your choices down to a couple, ask people about how they feel about their scopes, from the purchase to the maintenance, to how often they use them. You may need help after your new purchase, and the club members are often just the ones to assist you. You can also get some tips on where to go buying your scopes. Dealers that come highly recommended by club members often cost a little more, but what you get with the extra cost is the assurance that there'll be someone there to help you if misfortune strikes and you have a problem with your new scope.
Just in the day since writing this, I've received lots of other great suggestions. This first three come from John Steinberg:
Don't shine a flashlight at anything. This holds especially if it's a dark-sky party, as opposed to one that takes place in a city. You may find it disorienting in the dark, but flashlights ruin the dark adaptation of others, making it harder to see dim objects through the scope. Red flashlights, although used by amateurs to protect their night vision, are still too bright when shined directly at people and scopes. Don't do it.
Make sure your face and hands are clean. In the normal course of using a scope, these body parts are likely to come in accidental contact with optical surfaces. If they're not clean, they will not only leave dust on the lenses, but those lenses may get scratched, and grease is damaging to optical coatings. So lay off the cheeseburgers and pizza before using other people's scopes. And tone the mascara down if you must wear it.
Go star partying when you're well. For similar reasons, it may not be a good idea to use other scopes when you're sick. There are known cases of colds or conjunctivitis spreading through shared eyepieces. (No kidding!)
Here's another good suggestion from Ed Erbeck, Jr.:
Do make it known you're interested in buying a scope. As I said at the beginning of this article, I'm only providing one viewpoint—mine. (And with these contributions, those of some other readers.) You will get much more information from club members if they know you're researching purchases. You may get more than you want at first, but it's easier to whittle away the facts you don't need than to make up ones you don't have.
Thanks to all the readers who wrote in!
Copyright (c) 2000 Brian Tung