Amazon.com : Celestron - Zoom Eyepiece for Telescope - Versatile 8mm-24mm Zoom for Low Power and High Power Viewing - Works with Any Telescope that Accepts 1.25" Eyepieces : Telescope Eyepieces : Electronics
How to Choose Your Telescope Magnification - Sky & Telescope - Sky & Telescope
How can I pick the best eyepieces for my telescope?