More than you want to know, perhaps.
Hi,
I'm an astronomy professor, and get this question all the time from my students. You didn't say how much you already know, so I'll assume you're starting out.
There are two big questions to consider: what's your budget, and do you want to be able to take pictures through the 'scope?
If you want to spend less than $200 to $300, buy binoculars and a decent tripod instead. A pair of $200 binoculars on a steady tripod will show you more than a wobbly, cheap telescope that will end up in the back of your closet. Many people start with a scope in the $300 to $500 range, and if they get hooked, go on to a second scope in the same price range as a computer, $1,000 to $1,500. (Of course, I know an orthopedic surgeon with a $45,000 teak, mahogany, and brass scope looking out through a scratched-up plexiglass skylight in his bedroom!)
Buying a telescope is like buying a computer or being a good 'ler, it's all about performance. With a computer, you want the fastest machine you can get for your budget. With a telescope you want the largest diameter (aperture, they call it) for your money. If the tripod is sturdy (and most over $300 will be), everything else is secondary. Get the largest scope you can afford; you can always add accessories later.
Don't be fooled by ads for flimsy department store scopes that brag about the "power" (magnification) of the telescope. Any telescope can give you any magnification! Telescopes have at least two optical elements. There's the big lens or mirror that collects the light (the objective). It's the expensive heart of the telescope, and changing it would be like changing the processor chip in your computer. But then there's the little eyepiece lens on the other end. It's a lot cheaper, and they both affect the magnification. So when you own a telescope, you buy 2 to 4 eyepieces (at a few tens of dollars a piece), and swap them out to change the magnification. Since more magnification gives you blurrier images, you usually end up using low or medium magnification.
The choice of refractor (all lenses) versus reflector (an objective mirror) is pretty much irrelevant in the price range of beginning scopes, but if you go for a second scope in the $1000 range, you'll want to read up on the choices first.
The other big question is, do you want to take pictures? You'll need a camera that can take time exposures (a "bulb" setting), an adapter to fit the camera onto the telescope (often called a t-adapter which fits to an adapter ring specific to you camera body, usually a small few tens of dollars), and most importantly, a motor-driven telescope that will compensate for the Earth's rotation and follow the motion of the stars as they rise and set. That can add a couple hundred to the cost of your scope, but if you want to take pictures, it's well worth it.
A good place to check out brands is in the two major astronomy hobby magazines, Sky & Telescope (available at most book stores) or Astronomy (available at bookstores and many groceries). They only accept ads from reputable dealers. Both have buyer's guides in the January issues, and both have beginner's suggestions online at:
http://SkyandTelescope.com/howto/scopes/article_241_1.asp
and
http://www.astronomy.com/asy/default.aspx?c=ss&id=9
I also recommend finding your local hobby group. Most of them have public viewing sessions where you can look at and through a variety of scopes and talk to the owners - find out what they like and don't like.
Many motorized scopes today are "go to" scopes. You can use a handpaddle or connect to planetarium software such as The Sky on a laptop. After setting them up and telling them the time and location, you simply select an object from the list on the handpaddle, or click on an object on the sky chart on the laptop, and the telescope points to it. Great for finding lots of things quickly, but it can be a crutch that keeps you from learning your way around the sky, one of the real joys of the hobby. I have one but only use it when I just cant find things by "star-hopping" with a good chart.
Go easy on accessories to start. Get a scope with a sturdy tripod and maybe three eyepieces. Spend a little more for a good low-power, wide-angle eyepiece - you won't regret it! (I have a high power eyepiece that atmospheric conditions allow me to make use of a few times a year, but I spent $120 for a good low-power, wide-angle eyepiece that I love!) Get a good guidebook, and maybe some software that displays star charts (Voyager, The Sky, Starry Night are all very good, but top-end. You can download freeware to start, and there are places online like Heavens-Above.com where you can print out simple constellation charts, but they won't specifically show good telescope targets.) Things like filters can come later.
A personal hint. I'm often hearing from students who spent hundreds or over a thousand dollars on a good scope, took it out a few times, got disappointed, and haven't used it in years. Their problem was that they didn't learn what to look at. They pointed it at several bright stars, found they all looked alike, and gave up. At the beginning level, it's not about stars. It's about planets, nebulae, galaxies, star clusters, comets, etc., and you have to learn where to find them. Invest in a good beginner's guide book for telescope owners, with a decent set of star charts. My personal favorite, which I use routinely, is Nightwatch by Terence Dickinson. A good beginner's list of targets is the hundred or so Messier objects. Mr. Charles Messier was a comet hunter who created a list of nuisance objects he kept seeing and suspecting they were comets. The list includes many of the brightest star clusters, nebulae, and galaxies. [Since planets are always moving, you won't find them printed on the charts in books. You'll have to go to charts in magazines or online to find them.]
OK, enough rambling; I hope this helps! I'll shut up now!
Feel free to e-mail me if I can answer any questions.
🙂 E. Bunbury
y.
TOTALLY AWESOME!
