Why Telescope Optics Don’t Need to Look Perfect
Inspecting telescope optics can be misleading if you don’t know what to look for. Many astronomers worry when they see dust, sleeks, or marks on lenses and mirrors—especially when using a flashlight. In reality, these cosmetic imperfections have little to no impact on real-world observing performance. This article explains how to inspect astronomical optics properly, why the flashlight test is unreliable, and what truly matters when evaluating telescope and eyepiece quality: performance under the night sky.