What are the different types of telescope?

Refractor to reflector, Schmidt-Cassegrain to Maksutov-Cassegrain – this is everything you need to know about the different types of telescopes.

Telescopes gather and focus light using precisely-shaped mirrors and lenses (or a combination of both). The larger the telescope’s main mirror or lens, the more light is gathered and the more detail you’ll be able to see — this is important in the realm of astronomy, since many celestial objects are rather small and faint. Eyepieces are used to magnify the image focused by the main mirror or lens. There are three basic types of telescope: reflectors, refractors and catadioptric, but how do you which type is the best telescope for you?

The answer depends on how much you’re willing to spend, what you find most exciting about the night sky and whether that interest is going to stay with you for a good amount of time. For instance, if you’re a solar system observer and you would like nothing more than to gaze at the moons of Jupiter, the rings of Saturn or the craters and ridges of the moon then you should go for a powerful telescope that’s capable of achieving this. If you can’t decide and prefer to observe anything and everything in the night sky but you want a telescope that’s relatively easy to set up, then you should go for something a little cheaper and easier to use.

There are three basic types of telescope: reflectors, refractors and catadioptric. We’ll go into each type in detail below, so you know which type is right for you.

The refractor is the original telescope. In fact, it is such an iconic and classic design that when children are asked what a telescope looks like, they almost always draw or describe a refractor. Invented around 1609 — by whom, exactly, is debated — a refractor is essentially a spyglass, a tube with lenses at either end which work together to make faraway objects appear closer. This type of telescope was famously used by the great scientist Galileo to observe craters on the moon, sunspots and discover the four largest moons of Jupiter.

During the 1970s or 80s, most telescopes bought by amateur astronomers were refractors, because good-quality reflectors were just so expensive to produce. Today the tables have been turned and large reflectors probably outsell refractors. However, high-quality refractors remain the telescope of choice for astronomers wanting to enjoy detailed views of the moon and planets. Refractors perform so well on these objects because, unlike reflectors, their tubes are closed, which means less air moving about inside them which in turn means much less distortion of the image visible through them.

When purchasing a refractor it’s important to buy the best you can afford. The cheapest refractors have poor-quality lenses, which are often badly aligned. This results in images with distortion around the edges and colored fringes too. Refractors with the best quality lenses are very expensive compared to reflectors, but you really do get what you pay for.

We’d only really recommend cheap refractor telescopes for young kids who are just discovering the hobby. This is because they’re an inexpensive way to spark that interest, and you can get them a more expensive, better-quality model when you know if they’re sticking with it or not.

If you want to enjoy crisp, detailed views of Saturn’s rings, the cloud bands of Jupiter and the surface features of Mars, then a refractor is the telescope for you. It will provide much better views of those objects than a reflector of equal or even larger aperture. A refractor will also provide you with wonderful views of star clusters and double stars.

However, refractors do not perform as well as reflectors when turned towards the “faint fuzzies,” such as galaxies and nebulas, so if you are wanting to observe famous objects such as the Andromeda Galaxy (Messier 31) and the Orion Nebula (Messier 42) then a refractor might not be your best choice.

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