From the April 2007 issue

Glenn Chaple’s observing basics: Go-to a-go-go

April 2007: Go-to telescopes can help beginners navigate the night sky.
By | Published: April 1, 2007
Decisions, decisions! You’re about to purchase a telescope. Will it be a refractor or reflector? Should you place the instrument on an equatorial or alt-azimuth mount? How about the finder — an LED-powered reflex sight or a more traditional optical finder scope? No doubt about it, when it comes to scopes, you have a lot of options.

Consider the choice between a no-frills scope or one with go-to capabilities. The former requires familiarity with the night sky so you can locate each target; the latter lets you navigate the heavens with push-button ease. When go-to telescopes were first introduced 2 decades ago, they were touted as a panacea for the novice who couldn’t find sky objects with traditional scopes. Can’t locate the Andromeda Galaxy? No problem! Press a button on the remote, and your go-to will get you there.

There are drawbacks to the go-to option — cost being foremost. Let’s say your budget allows no more than $400 for a scope. For that money, you could pick up a quality 8-inch Dobsonian-mounted reflector. If you must have go-to technology, you’ll have to settle for a smaller instrument. Usually adding to this expense is the need for batteries to power the system — typically a set of eight AAs, which will provide about 20 hours of use. This could incur an annual expenditure of $50 to $100, depending on how often you use your telescope.

If money isn’t an issue, how about time? You can set up a standard telescope and begin observing after you’ve allowed your eyes to dark-adapt and your scope’s optics to acclimate to the temperature. Not so with a go-to scope, which may take 10 to 15 minutes to initialize. This normally requires leveling the tube and pointing it north, then sighting two or three selected bright reference stars. If you live in an area where trees or buildings block stars, this process may take longer.

A third strike against go-to technology is that it isn’t always user-friendly for the true novice. On several occasions, I’ve been asked to help a frustrated newcomer figure out how to operate a go-to scope. If you’re the type who doesn’t feel like spending an hour reading a manual just to program a VCR, go-to technology may not be for you.

With these warnings, you might think that I take a dim view of go-to instruments. Au contraire! The first time I tried a go-to scope, its capabilities wowed me. What an incredible experience to enter “M82” on the remote and watch the instrument spring to life as it sought out its quarry. To peer into the eyepiece after the scope stopped and see M82’s cigar-shaped glow was nothing short of amazing! Earlier, I noted that a go-to telescope requires a 10- to 15-minute set-up time. Being able to “go to” a target in a minute or two is far more time-effective than spending 10 minutes, or longer, fumbling with sky charts and a flashlight while observing with a no-frills telescope. Cruise the heavens with a good go-to telescope, and you’ll quickly become an advocate.

If money isn’t an issue, and you’re comfortable with technology, consider a 6- to 8-inch Dobsonian or catadioptric scope (Schmidt-Cassegrain or Maksutov-Cassegrain) with go-to capability for your purchase. Whatever you choose, just remember: A wise purchase of any telescope will enhance your enjoyment of backyard astronomy for years to come.

Questions, comments, or suggestions? E-mail me here.

Next month: We’ll take a look at finder scopes. Clear skies!