A Deficiency of Reflectors

Suzanna Nagy’s article on “What Kind of Telescope Should I Buy?” in the Sept/Oct 2016 edition of our Nova newsletter praised the Dobsonian design. A Dobsonian is a type of reflector telescope that uses two mirrors. Suzanna’s article listed several advantages of the Dobsonian design. However, a recent edition of XKCD has revealed a little-known deficiency of a reflector.

XKCD Webcomic: Telescopes: Refractor vs Reflector
XKCD  – Telescopes: Refractor vs Reflector