Save 20% on Select Astro-Tech Eyepieces

Four millimeters is the extreme end of useful magnification in a 1.25" eyepiece — the one you reach for when the atmosphere is dead calm and the pl...

Ten millimeters splits the difference between deep-sky and planetary magnification — high enough to resolve globular clusters and show structure in...

The 13mm is the transition point — high enough magnification to show real detail in globular clusters and planetary nebulae, low enough to hold a u...

Sixteen millimeters is the all-rounder focal length in a 1.25" barrel. In a 10-inch f/5 Dob, it gives you 78x — high enough to darken the sky backg...