Buying a Telescope

Buying a telescope has caused many amateur astronomers to pull their hair out. One frequently asked question is in the heart of the problem. What type of telescope should I buy? But if you are serious in buying a telescope, let me tell you that this is the wrong question. The one that you should be asking yourself is “What kind of telescope is best for me?”. Isn’t that the same, you might say? The short answer is no. Some telescopes are best suited for observing one object, others are better for astrophotography, and so on. The telescope that you want to get is the one that will best fit your needs.

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Before we continue let me make one thing clear. At the end of the day it’s your money on the line. Make sure you’ve done your research and know what you’ll do with the telescope you plan to get. OK, there are two things we should get straight. In case you haven’t notice, this website is oriented toward beginners, people who plan to start or have recently started to dive into the field of amateur astronomy. So, I’ll try to address the issue of choosing a telescope accordingly. One last thing, I promise :). Quality matters. Buying a good quality telescope, even with specs not as good as you have wanted, is better than buying a telescope that has cool specs on paper and is a piece of junk when you try to use it.

Remember the important question – “What kind of telescope is best for me?”. To answer it let see in which category you fall into. But also remember that the best telescope is the one you’ll use most frequently, not the one that will collect cobwebs in the basement for not being practical enough to be used.

New vs. used telescopes?

That’s a tricky one. Basically, it’s up to you. The benefits of getting a brand new telescope are obvious – excellent condition, warranty, etc. Getting a used telescope is a bit of a gamble. Unless, of course, you buy it from someone you know and trust to have taken a good care of the instrument. But even so there are no guaranties that it won’t break the first time you use it. On the other hand buying a used telescope could save you a lot of money. And good quality telescopes could last a while. I’ve used some very good scopes that were older than me. So you can get a good quality telescope for half of what is worth. As I said, it’s up to you.

I don’t have much money. Can I buy a telescope for $150-200, tops?

Yes and no. A piece of advice, you get what you pay for. Heaving said that, if you’re short on cash you might want to consider buying a binocular. I’m serious. For that much money or less you’ll get a very nice binocular. Nevertheless, you could find some decent scopes (up 4″ or even 6″) that would do an OK job. Such scopes won’t have the best quality optics or the sturdiest mount, so be aware. You get what you paid for. If you travel a lot, a small telescope/binocular might be what you’ll be looking for. Here are a few examples of what you would find out there:

I want to do stargazing. Don’t care much about astrophotography

Well then, you might get out of this without spending a fortune. Go for a low f/ratios – f/8 or less if possible. That would insure having bright images in your eyepiece. Although large apertures also help a lot :). Here are a few more questions to think about. Do you plan to use it in your backyard? If yes, then size doesn’t matter. If you travel to do your observing sessions and transporting the telescope could be tricky, you might prefer something smaller and more compact.

My suggestion for you is a Dobsonian system. They are easy to assemble and more importantly affordable, which means you could buy a telescope with larger aperture to fit you budget. The telescope’s optical system is Newtonian, which means the eyepiece is on the side of the tube. That could make hunting targets less comfortable than the rifle-like aiming of a refractor or catadioptrics. However, with a well-aligned guide on the telescope this should not be a problem.

Sun, Moon and planets

Observing or taking photos of the entire Sun or Moon, or having point-like planets could be done with almost any telescope. Finding details on the planets and getting close-ups of our Sun and Moon is a bit trickier. If you want to do this get a solid mount! When you are at such large magnifications every vibration is fatal. There is no point of getting a good telescope if every time you take a breath the system shakes. So before you even consider buying a telescope, make sure you’ve picked a solid tripod, and a good equatorial mount. I’ll recommend a German type mount, rather than the fork type. In my experience the German types are in general more reliable and sturdier.

About the telescope… Buying a telescope with f-stop of f/8-f/10 and maybe even more (~f/15) is recommended. That way you’ll have the proper focal length for your system. Granted, there are techniques to increase the focal length of your system, but a good start-up f-stop always helps.

I like to do some astrophotography

Again, a good, solid, equatorial mount is a must! It’s as simple as that. Whether you’ll be shooting through the telescope or do a piggyback astrophotography you must avoid vibrations at any cost. For piggyback astrophotography any good quality telescope with normal specs should be fine. As I said before be more picky with your mount.

If money is not an issue, you might consider getting an astrograph. Astrographs are high quality catadioptric tubes (although the cheaper versions are simple Newtonians) that are specifically built for astrophotography. Such scope can produce such stunning images that would make your friends jealous. And it better given how much money you have invested.

A note on Go-to telescopes

They are very good, very useful and… very expensive. If you have that much money and you think this is a feature you must have, who am I to stop you :)? I’d like to have one, too. One reason I would not recommend it for beginners is that you’ll rely heavily on this feature and won’t learn where different celestial objects are on the sky. Hunting down your targets manually will make you much more familiar with your instrument and the night sky. That’s why I think it would hinder your progress as amateur astronomer. Nevertheless, it’s your call.

My personal pick/recommendation

I would not recommend a telescope with aperture less than 6″ (150 mm). If you were to keep it for a while, and are not in the position to buy multiple telescopes, then this would be my minimum diameter. If you are on the move a lot and need compactness and mobility a 4″ (100 mm) would do. Less than that and you’d be better off getting a binocular.

If buying a telescope was on my to-do list and money not an issue, I would get 8-10″ (200-250 mm) with f/6-f/10. That would be a universal instrument that you could use for almost everything. I would go for good quality optics. Whether Newtonian or Cassegrain it’s up to you (or the depth of your pocket). I would rather get a Newtonian (10″ if I have any say in it) and save some cash to spend on a good equatorial mount (a German type if you haven’t guessed by now 🙂 ), than getting the catadioptrics.

But that’s just me. As I said earlier, it’s your money and your choice. Pick what would best work for you. Buying a telescope is an important step, so do your research in advance.

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