How to Choose a Telescope

How to Choose a Telescope

Like choosing neighborhoods, automobiles, or spouses, buying a first telescope is a highly subjective undertaking. There’s no “best” telescope for everyone. The one that’s right for you will depend on your lifestyle and your astronomy goals. Spending a little time analyzing your motivations will help you make an intelligent choice. Let’s look at the different types of telescopes, and in so doing, some of the considerations that might influence your buying decision.

Power is Not the Important Thing
The first point to emphasize is that magnifying power is NOT the most important consideration when choosing a telescope. Not even close. It is the telescope’s light-gathering capability, or aperture, that determines how much you will be able to see. Overblown claims of 450x or 575x power (or more!) in ads for inexpensive telescopes are pure baloney, and a sure sign of inferior quality. The brightest, sharpest images are obtained at much lower powers, on the order of 25x to 50x.

Refractor A small, quality achromatic refractor of 60mm to 80mm aperture makes a fine starter scope for observing the Moon and major planets. They’re inexpensive ($100 to $350), portable, and maintenance-free — all desirable factors if you’re just “testing the waters” of the hobby. Their small apertures aren’t well suited for faint deep-sky objects, though. If nebulas and galaxies are your main interest, a Newtonian reflector or Schmidt-Cassegrain is the way to go. Moving up to a 90mm or 100mm refractor will snare more objects and provide better performance, for a higher price. Renowned for crisp, sharp images, refractors are the priciest per inch of aperture of all telescope types. A refractor is the scope of choice if you will be doing most of your stargazing from city or suburbs, where the night skies are moderately light-polluted. Here, more aperture doesn’t gain you much, since viewing is restricted mostly to the Moon and planets. In fact, a big scope would only amplify the skyglow, yielding poor washed out images.

Newtonian Newtonian reflectors are great all-around scopes, offering generous apertures at affordable prices. They excel for both planetary and deep-sky viewing. Of course, the larger the aperture, the more you’ll see. Smaller, 3" and 4.5" equatorially mounted Newtonians will provide a nice “survey” of celestial luminaries, and they’re plenty portable. Six-inch and 8" Newts have enough aperture to deliver captivating images of fainter fare-clusters, galaxies, and nebulas-especially in a reasonably dark sky. The tradeoff is their bulk and weight — something you should definitely take into account before you buy. But a 6" Newtonian on a Dobsonian mount is easily manageable by one person, and makes a wonderful beginner scope. Dobsonian-mounted reflectors have lower price tags than their equatorial counterparts, starting in the mid-$300s for a 6" Dob.

SC If portability is important to you, you might want to consider a “catadioptric” scope such as a Schmidt-Cassegrain or Maksutov-Cassegrain. They pack a hefty aperture into a very compact tube. An 8" Schmidt-Cassegrain provides excellent views of the Moon, planets, and deep-sky objects, and is well suited for astrophotography. But an SC is a considerable investment for a beginner — over $1000 for the most basic 8" models (and hundreds more to outfit it for astrophotography). Although compact, an 8" SC is actually quite a lot of scope to manage when you include the beefy tripod and mount. So beware!


Telescope Mounts
A quick word about mounts. Telescopes come on three basic mount types: altazimuth, Dobsonian, or equatorial. The altazimuth is the simplest and is recommended for casual stargazing and terrestrial observing. The Dobsonian mount is a boxy altaz-type mount designed for easy maneuvering of large Newtonian tubes of 6" aperture or greater. Equatorial mounts are a bit more complicated (and more expensive) than altazimuth mounts, but allow the user to follow the motion of celestial objects with a single manual hand control, or even automatically with a motor drive — a great convenience.

The Bottom Line
OK, now that you’ve gotten the crash course on telescopes, here’s some parting advice for aspiring astronomers: Get as much aperture as you can reasonably handle, but not more.

Big aperture is desirable, sure, but you don’t want to end up with a scope that is too big or complicated to conveniently set up, haul around-and use! Also, avoid those gee-whiz, techno-toy scopes with the hefty price tags that are showing up in the big chain stores. For a first telescope, we recommend a basic refractor of 90mm aperture or smaller, or a Newtonian reflector of 6" aperture or less, unless you’re really committed. After you’ve learned the basics of observing and developed an appreciation for the hobby, then you can move up to a bigger, fancier scope.

This information is from Orion Telescopes website.

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