What to Know Before Buying a Telescope

Telescopes come in an overwhelming variety of sizes, shapes, and prices. To make sense of this embarrassment of riches, you need to ask yourself a few basic questions using this guide.

In this telescope buying guide, you'll find that telescopes come in a variety of sizes, shapes and prices!
The author owns a half dozen scopes, including the 70-mm refractor at left and the 12.5-inch truss-tube Dob at right.
Carla Procaskey
How much are you willing to spend? How portable does your telescope need to be? Do you plan to do astrophotography? Why are some telescopes made with mirrors,others with lenses, and some with a combination of the two? What is the difference between a 25 mm eyepiece and a 10 mm? What is a finder scope for? What is Go To, and do I really need it? And what do you hope for and expect from astronomy?

Questions like this can be daunting, especially if you don't know any amateur astronomers  yourself. This guide can answer these important questions to help you start out on the right path when selecting your first instrument to choose the right one to fit your needs and interests: some telescopes are better suited to observe, say, the planets more so than observing galaxies and nebula.

If you shop really carefully using this telescope buying guide, you can buy a good telescope for $100. At the opposite end of the spectrum, we wouldn't hesitate to recommend a telescope costing $2,000 or more to a beginner who is really committed and knows exactly what he or she wants. For most people, the best first purchase might not even be a telescope; a good pair of binoculars will serve you much better when starting out in observational astronomy. And the binoculars will still be handy when you do move up to a telescope.

For a quick overview of what telescopes are all about, see our article Choosing Your First Telescope.

For a more comprehensive discussion of astronomical equipment, download the article What to Know before You Buy from the 2010 issue of SkyWatch, our annual magazine.

12 thoughts on “What to Know Before Buying a Telescope

  1. Anthony BarreiroAnthony Barreiro

    I would advise beginning skywatchers to get a good pair of 10×50 binoculars and to spend a year or two learning to observe the sky through binoculars before getting a telescope. Binoculars are less expensive, much easier to use, and they will show you a much broader area of the sky than the very narrow view through a telescope eyepiece. I have several very good telescopes, but I still use my binoculars much more often than any of my telescopes, simply because it’s so much easier to grab the binoculars for a quick trip out to the back yard or up the hill, without the hassle of lugging, setting up, and breaking down a telescope. A search for "binoculars" here on skyandtelescope.com will lead you to a number of helpful articles.

  2. Ken Renard

    I would agree with Anthony for starting out binoculars are great and you can always use them for years to come. I use my 10 X 50 almost every day. I must say my small 72 mm refractor gets a great deal of use. Its always set up and I can be observing in a few seconds. I was able to look at Saturn and Venus this morning before leaving for work. I have brought the small refractor on trips and carry it around the yard. It also works great for birds and wildlife. Either binoculars or a refractor with a wide field of view will help in learning the sky and makes finding things a bit easier. I am often amazed at what I can see with such a small scope, even in my own backyard. I have had it in dark skies and its amazing.

    My daughter has a skyscanner 100 (mentioned in the article above) which is a great scope for a kid. She is 6 and can play around and you don’t have to beak the bank. We mounted it on a small wooded box with a bolt. Its perfect kid height and is fine for adults as well. We built a sun funnel for it and show all the kids in the neighborhood the sunspots. Just about every day we have out at least one or the other. If you take your time to look most scopes will show you so much.

  3. Anthony BarreiroAnthony Barreiro

    Ken, you’re right! My 70 mm refractor gets a lot more use than any of my bigger telescopes. I took it to Hawaii to watch the transit of Venus, and it performed admirably.

  4. Al


    I read your article with great interest as I am in the process of going from an 8" Celestron NexStar to the largest possible (aperture) telescope (with GoTo system) for star parties, outreach, some astrophotography and possibly spectroscopy (for undergraduate research).

    I am considering a 16" Dobsonian with GoTo system such as this one:

    I would greatly appreciate your input on this choice.



  5. Ted Hauter

    Bino’s with image stability is the only way to go. They are a $1000+ SO..

    Even if this is your first day in astronomy, I highly recommend spending $2500 on a good 8" SCT with GOTO, with a binoviewer or good eyepieces, battery packs to run the goto, a Telrad finder, and star charts, plus maps on your phone.

    If it doesn’t pan out, you can sell this easily for only about a $800 loss – a cost of getting into the hobby. Which is nothing, ask any veteran amateur.

    But it will pan out right? All you need is interest.

    If I had taken this advise, I would have saved around $800 messing around with starter equipment.

    Money that can go towards those IS binos you will need.

  6. Anthony BarreiroAnthony Barreiro

    Ted, I just read your comment, only 15 months late! I disagree that image stabilized binoculars are “the only way to go.” Yes, if you can afford to spend $1300 for a pair of image stabilized 15×50 binoculars, they’re wonderful. But if $100 to $200 is within your budget, you can get remarkably good standard binoculars, without the image stabilization gizmo. Standard binoculars are also much lighter than image-stabilized and don’t need batteries, which always seem to die just when you need them most. I hope that nobody will be discouraged from binocular skywatching because they can’t afford image stabilization.

    1. Ted-Hauter

      Hi Anthony, I have sat down to study the S&T website, and can respond to your comment, only 5 months late! Hopefully regular binos do not go the way of the dinosaurs for the sake of budget minded souls entering the hobby and business, but these are old tools now. Get image stabilized. All beginners should save up for at least 30/40mm IS binos. These can easily be sold for that $800 loss – the cost of getting into the hobby.

      Everyone wants to image a galaxy, see the moon, the planets, wide field areas of the sky to behold, and with a safe filter on the front of the telescope, the sun. All of these actually require different equipment. The closest one can get to covering all these targets is an 8″ SCT with GOTO, low power eyepieces that can then be magnified higher with a Denk bino, a solar white light filter, and a DSLR camera with adapters.

      Where there is no light… there is the night.

  7. Miguel-Garcia

    #1. I tried binoculars first but got frustrated because other than wide star fields I could not see anything like a planet or nebula because of the shaking. It was frustrating. I do not know how people can recommend binos for newbies

    #2. Bought a 6″ SCT but got frustrated because planets were too small ( even jupiter), returned it and got an 8″ newtonian following advice from a fellow astronomer, on a solid goto mount ( Celestron AVX). 3 months later I’m still working the kinks of the collimation ( it is a fast f/4 newtonian) . I did not know fast newtonians are not good for planetary. Still, I will keep it as i’m amazed at the images of deep space objects. Lots of money into accesories, collimation tools, etc ( 10 times what the scope was worth)

    #3. Now looking for a SCT with long focal length so I can see and image planets, and hopefully avoid most of collimation and flexure/focuser shift problems.

    My 7 year old son bought a 4.5 newtonian in a manual equatorial mount without motors. This is the scope he and myself use the most because is very easy to take outside…5 minutes between we grab it and we are looking at jupiter….no messing with polar alignment, computer, etc.

    #4 I would have loved someone to tell me in advance this:
    – First buy an uncomplicated scope, like a mak-cass or small long focal lenght scope in a decent manual mount, preferably alt-az, so you can learn the basics and spend your time actually LOOKING not trying to fix issues, pointing, etc and buying much more required accesories. Spend probably no more than $350, no less than $200 or a cheapo telescope/mount will frustrate you. If YOU LIKE IT AND YOU ACTUALLY FIND OUT YOU HAVE THE TIME you”ll know better where to go next….worst case you can sell it and not much harm will be done ($300 IS NOTHING compared to what you”ll likely end up spending if you get into the hobby)

    #5 Newts/dobs are great, BUT. You need to collimate them. They are likely not going to be collimated properly from factory so you will have to BUY COLLIMATION TOOLS RIGHT OFF THE BAT. Laser collimators are useless because they need to be collimated first, and YOU CANT ALIGN A NETWONIAN SECONDARY MIRROR WITH A LASER. You need the sight tube…so be prepared to AT LEAST spend another $50 in a good sight tube/cheshire. In fast imaging newtonians COLLIMATION IS CRITICAL…you will need to spend as much money as you spent on the scope on center spotting it and accurate collimation tools ( like Catseye sight-tube/cheshire+ autocollimator). Unless you invest in a carbon fiber OTA, long newts have FLEXURE, so either you need to live with it or be prepared to collimate often right there when positioned.

    #6 Be prepared to spend twice or three times as much you spent on the telescope in ACCESORIES. The stock focuser, eyepieces, diagonal, etc manufacturers ship with the standard scope are usually CHEAPO parts to get you going, but any more or less serious amateur astronomer will end up buying the required parts to get the scope working at its intended potential, including a decent focuser, finderscope/telrad. Besides this you’ll need a dew controller/heaters, for goto scopes an external battery ( AA batteries will not last much or do not work at all with the mount’s motors). For astrophotography you’ll spend much more, actually you’ll never stop buying accesories: focusing adapters, filters, imaging capture/processing software, coma corrector, light pollution filter, polar scope, cables, camera power adapter, light box/panel for taking flat frames, etc.

    Despite this I’m still enjoying the hobby….just beware what you are getting into.

  8. A-T

    All of those problems could have been avoided by doing thorough research before buying. Even a casual look around on buying guides and amateur astronomy resources can tell a person that, for instance, long focal ratios are optimal for planetary observing while short ones are better for deep-sky. It is also a widely known fact that Newtonian telescopes and especially Dobs need to be collimated.

    The procedure of buying telescopes, finding out that you don’t like them, and selling them again or returning them is also entirely avoidable. Find a specific model that looks like it could work for you, read reviews about it, ask people who have it, maybe even try to find some photos done with it so you can get a realistic expectation (well, to the extent that astrophotography can give) of what to expect in the eyepiece. If you can, meet with some astronomers, at a club perhaps, and try out their equipment so you can get a feel for what sort of thing you like. If you are spending a lot of money buying things blind, you’re doing it wrong. The internet is your friend.

  9. Miguel-Garcia

    I did some extensive research…there is a sea of posts and reviews and forums, the stuff that matters is not evident to the “untrained” eye…as I said, I’m not complaining, I’m a happy camper, just don’t like much to be surprised. I just would not advise on getting binoculars but tell the truth…the ‘devil’ is in the details.

  10. Martin-Lewicki

    You need both really – binoculars and a telescope. Binoculars only will drive you nuts without a telescope. You will want a telescope to check out that cluster or fuzzy spot you just picked up.

    True about small scopes. I use my highly portable ETX90 on a table-top more than my 6-inch Newtonian. I don’t even bother with the GOTO as it wastes my time. I now know the sky well enough now to rely mostly on my hand-brain “goto”.

    Choosing a telescope is like choosing the right kind of car. You get something that suits your life style and pocket. So test driving at star parties is a good idea but not perfect. It is not until you are finally out there with a scope on your own using it unfettered by a barrage of opinions and distractions that you get to know if you got the right one for you.

    If you talk to the veterans I’d bet they went through a telescope or two before they settled on the one that works for them. And times change too. After a while when you know you scope (and sky) really well and new scopes appear on the market you will probably know what your next (upgrade) scope will likely be.


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