«

»

May 18

Telescope Buying Guide

Buying a telescope might seem like a really straightforward idea when you first look into it. After all it’s just a case of heading to the nearest mall and asking what telescopes they’d recommend right? Unfortunately that’s the wrong way to go about it and you really, really need to do your research before you spend a cent on a telescope or any equipment that comes with it.

Telescope Buying GuideYou see the vast majority of the telescopes you’ll find in malls aren’t even worth the $50 or $100 they’re charging for them, and they definitely won’t deliver the results you’re expecting either.

So what we’ve done is put together a telescope buying guide for you to explain all the little details you need to be aware of before you go spending your hard-earned cash on a telescope that simply isn’t worth the money.

The Different Types of Telescopes

Even though all telescopes may look the same from the outside there are some pretty big differences in how they function, and just how good the images of our Moon, Jupiter or Saturn will look when you’re gazing through the eyepiece.

Refractor

This is the type of telescope you’re most likely to find in stores across the country and also tend to be some of the most affordable. Unfortunately most of the trashscopes you’ll find retailing in these same stores are refractors, which tends to give them a bad name. A refractor works by focusing the light it collects through a lens and into the eyepiece itself and is capable of producing very high levels of contrast and crisp images.

Another bonus with refractor telescopes is they can be used during the day and at night time too. The longer the focal length of the refractor then the better your viewing experience is going to be. Most refractor telescopes tend to be pretty much maintenance free too which is handy.

Reflector

These are also known as Newtonian telescopes, because they were invented by the famous physicist Isaac Newtown, but when you hear people talking about a reflector telescope and a Newtonian scope they’re talking about the exact same thing. This type of telescope uses at least at least one large mirror to reflect the light from the back of the telescope towards a focuser set at the front. You’ve probably seen a reflector telescope before – they’re the ones where the person is standing to the side of the telescope instead of at the rear of it. If you’re serious about getting involved in astronomy then investing in a reasonably priced reflector telescope is the best way to get started.

The one major downside to a reflector telescope is that it can’t be used during the day – well not unless you enjoy seeing everything upside down of course. It’s also worth mentioning that the mirrors in a reflector can get out of alignment and you’ll need to perform something called collimation, to fix that particular problem.

Compound

People will refer to these telescopes as catadioptric, compound, Maksutov-Cassegrain and Schmidt-Cassegrain, but again they’re all basically the same thing. To produce images this type of telescope uses a combination of lenses and mirrors to provide you with large amounts of light grasp but in a compact design – unlike some of the larger refractor and reflector telescopes.

When you’re using a catadiopter your viewing position is the exact same as when you’re using a refractor – you stand at the rear of the telescope. Compound telescopes are popular because they require very little maintenance and are usually pretty portable by telescope standards.

The Different Types of Mounts

Having a great telescope, in terms of the optical tube, is obviously a good start when it comes to stargazing, but even the best telescope can produce a very poor user experience if you’re using a poorly constructed mount. If you’ve just spent $50 or $100 on a trashscope you probably have a wobbly wooden or aluminum stand and an equally poor fork mount, which means you’re going to spend most of your time adjusting the telescope to get anything like a decent view of the moon, stars or other celestial objects.

Understanding the basic differences between each type of mount can save you an awful lot of trouble and expense, so we’re going to take a look at each type in a bit more detail.

Equatorial Mount

You’ll find EQ (equatorial) mounts fitted to both refractor and reflector telescopes, although you’re more likely to find them on higher-quality telescopes because they’re generally aimed at more serious astronomers. In simple terms an equatorial mount allows a telescope to be positioned based on two different axes, one of them is angled towards the celestial pole and the other axis allows your scope to move at right angles to the polar axis. So instead of the clunky mounts you’ll find on cheaper refractors an EQ mount allows you to very accurately and slowly (via a number of slow-motion controls) track any celestial object in the sky above you, regardless of its position.

Dobsonian Mount

You’ll hear people talking about Dobsonian telescopes but what they’re usually referring to is a Newtonian telescope mounted on a Dobsonian mount. This particular type of telescope mount is based on a very simple mechanical design created by John Dobson in the 1960s. Instead of a complicated system of wires, controls and clutches a Dobsonian mount is basically a very sturdy Lazy Susan, acting as the base and then the optical tube (or truss) is mounted in a fork which allows the optical tube to tilt upwards and downwards. This type of mount is very popular with fans of reflector telescopes and they make using a telescope an easy affair for almost any member of your family because you simply rotate it to the object you want to view and that’s it – even on Dobsonians with huge apertures of 25-inches or more.

Aperture

There are a lot of things you need to look for in any given telescope but aperture always needs to be at the top of your shopping list. In basic terms aperture is a measurement of how much light your telescope can gather, and the more light it can gather then the clearer and crisper your images are going to be.

The amount of light your telescope can gather (something called light grasp) will depend entirely on the size of the mirror or lens you’re using. When it comes to looking at objects in our own solar system then an aperture of about 4-inches is fine but if you’re interested in deep-sky or Messier Objects then you’ll need an aperture of 6-inches or more.

Eyepieces

There are so many different types and sizes of eyepieces out there that it can intimidate people who are just taking their first steps in astronomy as a hobby. After aperture you’re going to find that eyepieces are the next most important part of your astronomy experience, remembering that this is the component which focuses all the light that your telescope has managed to grab from the sky. The most common types of telescope eyepieces are Kellner and Plossl, both with their own advantages. Most of these eyepieces aren’t massively expensive and a Kellner or Plossl with a 50-60 degree field of view will give you a breathtaking stargazing experience, for no more than around $70.

A Final Word

Hopefully our telescope Buying guide has given you enough information to now make a more informed choice when buying your first telescope.

If nothing else understanding the basic terminology involved means you won’t get conned by anyone.

Be Sociable, Share!