Astrophotography Tips Part 1: Choosing A Telescope / OTA

01/22/2016 Facebook Twitter LinkedIn Google+ Astrophotography Help Articles

Choosing a telescope

Understand the advantages and disadvantages of popular scope types.

Part 1 of the easy to follow beginners guide to choosing the right telescope or OTA (optical tube assembly). This is a must see video by Forrest Tanaka and explains the details for beginners of the different types of telescope commonly available today.

Types of Telescopes


You’ll encounter three basic types of telescopes:

The three basic telescope designs use different optics to achieve the same result: making distant objects look bigger and brighter than they appear to your eye. See the text for links to animations that show how light passes through the optics of each design.

  • Refractors have a lens at the front of the tube — it’s the type you’re probably most familiar with. While generally low maintenance, they quickly get expensive as the aperture increases.
  • Reflectors gather light using a mirror at the rear of the main tube. For a given aperture, these are generally the least expensive type, but you’ll need to adjust the optical alignment periodically — especially if you bump it around a lot.
  • Compound (or catadioptric) telescopes, which use a combination of lenses and mirrors, offer compact tubes and relatively light weight; two popular designs are called Schmidt-Cassegrains and Maksutov-Cassegrains.


Telescopes and OTA buying guide by Forrest Tanaka

Find Used Telescopes For Sale Here