What telescopes are suitable for what kinds of observing?

Keep in mind that a good  telescope, whatever its type, will repay you with a lifetime of enjoyment. It can't be used up or worn out. A poor telescope, on the other hand, will wind up unused in the back of a closet after only a few weeks of shaky and frustratingly inadequate views.

Buying a small, inexpensive "beginner's" telescope to see what astronomy is like, before you move up to a "good" scope, is often a guarantee that you'll never buy a good scope. Most inexpensive "department store special" telescopes have dim and blurry plastic optics, with shaky and difficult-to-use mounts. They can easily get you so discouraged at not seeing anything fun that you'll give up on astronomy without ever knowing how many wonders can be seen with a truly good scope.

So be prepared to spend at least $250 to $500 for a telescope – more, if possible. Try to make your first purchase a quality telescope, even if you have to wait a while to buy it. You'll be happier with a well-made telescope – from your very first look and for many years to come. But even at these prices, with today's technology, you can get a fully computerized telescope that can take the guesswork out of astronomy – a scope that will find, identify, and track celestial objects for you automatically!

That being said, we are aware that some people have strict budget limits. Others are looking only for a small scope as a present for their child or grandchild, spouse, or significant other. They are not looking for a serious observing instrument, simply a somewhat grownup version of a toy telescope for an occasional peek at the Moon or planets from the patio on a warm summer's night. 

For these people, we do have scopes that are well under $250 in the 60mm to 4.5" aperture range that offer quite acceptable visual performance at very economical price points. They are fun for occasional casual peeks at the sky, but they do have their limitations. You will have to track down objects in the sky on your own, as you won't have a computer to do the finding for you, and they rarely have motor drives to follow the objects once you've found them. People usually enjoy astronomy more if their first scope is more than just a bare bones and undersized "starter" scope.

If $250-$500 is more than your budget allows now, and you're looking for a telescope for some serious star-gazing, consider joining an astronomy club. You can attend their star parties for occasional observing and possibly find a member who would welcome your company while observing. Very often the club will also have a "loaner" scope you can borrow while you save up for the scope you really want. Don't buy something that's less than you really want, just because it's in your price range now. If you do, sooner or later you'll want something better, and much of your present investment will go to waste if you can't sell the too-small scope you bought "just to get started."

As you start your search for the right telescope, give some thought to whether you only want to experience the skies with your own eyes, or whether you also want to photograph them so you can share with others the sights you've seen. Astrophotography usually requires an equatorial mount, motor drive, camera adapter, a DSLR camera or CCD imager – things that aren't needed for visual observing. So, if photography intrigues you, plan ahead. Choose a scope that you can use for photography later, even if it costs a little more now. It will be more cost-effective in the long run to pay a little bit more to get a photo-ready scope now, rather than have to buy a completely different scope later.

If you refer to the discussions on the following links about "Why Buy a Reflector . . . a Refractor . . . a Catadioptric," concerning the virtues and drawbacks of the different scope types, as well as to the charts in these sections, you can narrow down which telescope types are best suited to your specific requirements. For example, if your main interest is the planets, the Performance chart in the previous section, combined with the Purpose chart below, might lead you to conclude that either a 6" f/8 reflector, a 4" refractor, or a 3.5" catadioptric might be the most suitable for you optically. But – if you have to transport your scope from home to a distant site each night to observe, the catadioptric's greater portability might well be the most important consideration, as will be seen in the Portability and Light Pollution chart in the next section, "Where Can You Use the Scope You Choose."

PURPOSE – WHAT KINDS OF TELESCOPES ARE SUITABLE FOR WHAT KINDS OF OBSERVING?

Refracting
Telescopes
Will the instrument be used primarily for lunar and planetary observing? Will the instrument be used primarily for deep space observing? Will the instrument be used for (1) lunar and planetary or (2) deep space photography? Will the instrument be used for terrestrial viewing during the daytime?
60mm (2.4") to
102mm (4")
altazimuth mount refractors
Recommended, except can be difficult to find and manually track objects at high powers. 60-70mm have limited capabilities. 80-102mm much more suitable. (1) Lunar snapshots a possibility.
(2) Not suitable.
Quite good, although field of view can be narrow.
60mm (2.4") to
152mm (6")
equatorial mount refractors
Highly recommended, but best in apertures above 70mm to 80mm. 60-70mm have limited capabilities. 80mm and up are more suitable. (1) Very acceptable
with drive.
(2) Very acceptable, if 4" and larger.
Usually unacceptable,
as mount is inconvenient to use.
Reflecting
Telescopes
Will the instrument be used primarily for lunar and planetary observing? Will the instrument be used primarily for deep space observing? Will the instrument be used for (1) lunar and planetary or (2) deep space photography? Will the instrument be used for terrestrial viewing during the daytime?
4.5" to 8"
equatorial mount Newtonian reflectors
Recommended,
if focal ratio is f/6
and above.
Recommended, particularly 6" to 8" apertures. Best from dark sky sites. (1) Recommended.
(2) Recommended in
6” and 8” apertures at f/6 and below.
Not suitable.
10" and larger equatorial mount Newtonian reflectors Acceptable, if an aperture mask or eyepiece filter is used to reduce glare. Highly recommended, if used from dark sky sites. (1) Acceptable.
(2) Highly recommended.
Not suitable.
6" and larger
altazimuth mount Dobsonian reflectors
Acceptable, but an aperture mask or eyepiece filter is recommended if 10" or larger. Highly recommended, 10” and larger best used from dark sky sites. (1) Not suitable.
(2) Not suitable.
Not suitable.
Catadioptric
Telescopes
Will the instrument be used primarily for lunar and planetary observing? Will the instrument be used primarily for deep space observing? Will the instrument be used for (1) lunar and planetary or (2) deep space photography? Will the instrument be used for terrestrial viewing during the daytime?
5" to 9¼" Schmidt-Cassegrains Recommended in all sizes, from all
observing sites.
Recommended, particularly 8" aperture and larger from dark sky sites. (1) Recommended.
(2) Particularly recommended in larger sizes.
Suitable in smaller sizes, if it can be used in altazimuth mode.
10" and larger Schmidt-Cassegrains Acceptable, but performance usually limited by seeing conditions. Highly recommended, but best if used from dark sky sites. (1) Recommended.
(2) Highly recommended.
Generally not suitable for
daytime use.
3.5" to 7" Maksutov-Cassegrains Highly recommended. Dark skies and 7" aperture needed for best performance. (1) Excellent.
(2) Acceptable in 7",
but long focal ratio a drawback.
Suitable in smaller sizes, if can used in altazimuth mode.
Binoculars Will the instrument be used primarily for lunar and planetary observing? Will the instrument be used primarily for deep space observing? Will the instrument be used for (1) lunar and planetary or (2) deep space photography? Will the instrument be used for terrestrial viewing during the daytime?
35mm to 70mm binoculars Acceptable to good for lunar. Not suitable for planetary. Respectable performance in 50mm to 70mm sizes, adequate in 42mm
and below.
(1) Not suitable.
(2) Not suitable.
Very suitable in all sizes.
80mm and larger astronomical binoculars Acceptable to good for lunar if tripod mounted, somewhat usable for planetary in higher powers. Good performance on large scale objects. (1) Not suitable.
(2) Not suitable.
Suitable, if tripod mounted.
Spotting Scopes Will the instrument be used primarily for lunar and planetary observing? Will the instrument be used primarily for deep space observing? Will the instrument be used for (1) lunar and planetary or (2) deep space photography? Will the instrument be used for terrestrial viewing during the daytime?
Refractor
spotting scopes on photo tripod
Acceptable, except difficult to track at high powers. Limited deep space use in small apertures; respectable in larger sizes. (1) Marginally useful, but not recommended.
(2) Not suitable.
Very suitable.
Catadioptric
spotting scopes on photo tripod
Acceptable, except difficult to track at high powers. Limited deep space use in small apertures; respectable in larger sizes. (1) Reasonably useful for lunar shots.
(2) Not suitable.
Very suitable.

Click on this "Where Can You Use the Scope You Choose"  link and we'll take you to the next step in choosing the right telescope for you.



. . . our 35th year