How To Pick A Telescope

For some beginner astronomers finding the right telescope can seem like a daunting task. To help beginner astronomers, we have created this simple guide to offer some help on what every newcomer needs to know and ask themselves before purchasing their new telescope.

Let’s start with types of telescopes.  There are 3 types of telescopes: reflecting telescopes, refracting telescopes, and cassegrains. What’s the difference?

Refracting telescopes are the probably the most common telescope around. They use lenses instead of mirrors and the eyepiece is located at the bottom of the telescope. It should be noted that images from refractors are mirror images and can be corrected using an erecting prism, but doesn’t have a large effect on your viewing experience. Refractors are easy to use due to the simplicity of design.

Reflecting telescopes use a mirror, instead of a lens, and the eyepiece is located at the top side of the main tube. Reflectors usually have larger apertures which mean excellent viewing of faint deep sky objects, but generally, they are not suited for terrestrial use.

Catadioptric telescopes or Cassegrain Telescopes, use a combination of mirrors and lenses. These telescopes usually have a nice modern design and have 3″ and larger apertures. Two of the popular cassegrain designs are the Schmidt-Cassegrain and Maksutov-Cassegrain. These are some of the most versatile type of telescope with excellent lunar, planetary and deep space observing plus terrestrial viewing and photography, but tend to be more expensive than reflectors of equal aperture.

A mount is an important part of your telescope and determining how easy it is to follow a star while viewing it. There are two basic telescope mountings: Equatorial Mounts and AltAzimouth Mounts.

An Equatorial mount, simply put, allows users to follow the rotation of the sky as the Earth turns. This is a great help when you’re trying to find your way among the stars with a map.

The Altazimuth mounts in contrast have a simpler design, meaning they just swing up, down, left and right. You have to move the scope every so often to follow the stars, moons and planets as the earth turns.

One of the more important features of a telescope is the Aperture. Aperture refers to the diameter of the telescope’s main optical component. The size of your telescope’s aperture determines how much light it can capture. The more light that is captured the more objects you can see in the night sky. More light also means greater clarity in the images you see. When selecting the aperture of your telescope, be sure to ask yourself where you want to use your telescope. If you are thinking about your backyard then having a large telescope will be great. If you have plans to take the telescope to darker skies, you will need something smaller and more portable, but still powerful.