7 Best Telescopes for Viewing Planets and Galaxies: Reviewed

Buying Guide: Telescope For Viewing Planets and Galaxies

The best telescope for viewing planets and galaxies has two essentials: high-quality optics and a steady, smoothly working mount. You may also want the telescope to be nice and large, but don’t forget portability and convenience.

Features To Consider When Choosing A Good Telescope To View Planets

Aperture

Aperture is the diameter, usually measured in millimeters, of the objective (primary) lens or mirror of the telescope. Essentially, the larger the aperture, the brighter images will appear, and the deeper into space you will be able to see.

Focal length

Focal length is the measurement, again in millimeters, from the objective to the eyepiece. This length directly affects the magnification potential of the telescope when paired with an eyepiece.

The distance can be a literal linear measurement from the primary lens to the eyepiece, as with a refractor; or a theoretical distance based on how the light is bounced from primary to secondary mirrors and then into the eyepieces.

This theoretical distance, used with reflectors and catadioptrics, will create a focal length that is longer than the actual optical tube—making the OTA more portable while significantly boosting the magnification potential beyond a similarly-sized refractor.

Focal ratio

Focal Ratio is a term that will be familiar to photographers, but it is important to certain astronomers, as well. This term is defined as the ratio between the focal length of the scope and the aperture.

Eyepieces

Eyepieces determine the magnification and field of view of a telescope. Different eyepieces are used to view different objects.

Some objects, such as nebulae and star clusters, appear quite large and are best viewed at low magnifications (which give a wider field of view), whereas planets appear very small and are normally viewed with high-magnification eyepieces.

Finderscope

A good finderscope is essential for any telescope. It brightens and magnifies the view, allowing you to find things beyond the naked-eye limit.

When properly aligned, a finderscope also allows you to point a telescope more precisely than do peep sights or reflex finders. This is especially important whenever you’re aiming at a blank point in the sky where your charts tell you an interesting, faint object ought to be.

Types Of Telescopes

1. Refractor Telescope

When most people think of a telescope, the refractor type is what’s going to pop into their minds. This kind of telescope uses a lens to focus light on a single mirror, which is angled to direct the light through an eyepiece into your eye.

The simplicity and reliability of the design makes it easy to use and requires little maintenance. These are excellent for observing objects, planets, the Moon and the galaxies.

Since the optical system is basically a straight line, there are no obstructions from secondary mirrors as there are in Newtonians or catadioptrics.

2. Reflector Telescope

Reflector telescopes feature a clear piece of glass or plastic at the front of the tube. These don’t warp the light, so they aren’t lenses, but instead a protective shell to keep dust out.

A mirror sits at the back of the tube. It’s curved to focus light on a second mirror, which directs light through the eyepiece and to your eye.

Reflector telescopes are easily identified by the fact that the eyepiece is found near the telescope’s front. These tend to be the least expensive, and you can get larger apertures for a lower price than with other models. 

3. Compound Telescope (Catadioptrics)

Compound telescopes use an initial lens to focus light onto a mirror at the back of the telescope. The mirror focuses light onto a smaller mirror mounted on the back of the lens, which directs light through a tube that runs through the center of the first mirror and out the back of the telescope.

Compound telescopes are very lightweight relative to other types, and they don’t require collimation like reflector telescopes do.