Telescope Optics Topics

by Bryan Greer

Why Should I Care How My Telescope Works?

A thorough understanding of optics is certainly not required to enjoy amateur astronomy. However, some knowledge of what makes your scope perform at its best will increase the frequency of those memorable views. Poorly performing telescopes rob from your enthusiasm in the hobby — especially if you are a beginner.

This website is a repository for my personal research, along with additional information to go along with my magazine articles. Much of it is specifically about the Newtonian telescope design, but the rest is more generic. If I think something might be of interest to even a few people, I put it here. The links provided at the bottom are sources of information I consider to be some of the best on the Internet.

Site updated Oct. 19, 2023

Companion web pages for Sky & Telescope magazine articles

September 2000 Sky & Telescope article download page (with videos).

  • Download the September 2000 Sky & Telescope in PDF format ("Understanding Thermal Properties in Newtonian Telescopes")

May and June 2004 Sky & Telescope articles download page (with videos).

  • Download the May 2004 Sky & Telescope in PDF format ("Improving the Thermal Properties of Newtonian Telescopes - Part 1")
  • Download the June 2004 Sky & Telescope in PDF format ("Improving the Thermal Properties of Newtonian Telescopes - Part 2")

PDF files provided with permission from Sky & Telescope magazine. Thank you!

More Newtonian telescope thermodynamics articles

Tips on attaching a temperature probe to your telescope

Using fans with Newtonian telescopes

February 2008 Note: Gary Seronik wrote an excellent thermal FAQ in the January 2008 issue of Sky & Telescope magazine. It summarizes the most important issues regarding thermal problems in Newtonians, and is a good place to start if you're new to this topic. (Oct. 2023 update: I'm aware that unfortunately these back issues are no longer available from Sky Publishing, but I'll leave this note posted for those that collect the back issues.)

Other optical articles

Try this at home! Simple tests you can do with your telescope

How atmospheric seeing affects telescopes with different focal ratios

Animated focal plane illumination map

Properties of various mirror substrate materials

Adventures in collimation

About the author. Feel free to contact me at if you have questions or comments.

Copyright 1997-2023 Bryan Greer