Telescope Calculator & Guide

Telescope Calculator & Guide helps visual observers understand how a telescope and eyepiece combination will perform before heading outside. CALCULATE YOUR VIEW • Calculate magnification, exit pupil, true field of view, focal ratio, and useful power ranges • Include Barlow lenses and eyepiece apparent field of view • Get clear guidance when a setup is too dim, too bright, or beyond a practical magnification limit ORGANIZE YOUR EQUIPMENT • Save multiple telescopes, eyepieces, and Barlow lenses • Keep calculations on your device for quick reference • Compare up to five eyepieces on the same telescope PLAN A BALANCED KIT • See high-power, all-round, and wide-field eyepiece targets for your telescope • Spot duplicate focal lengths before buying more gear • Open practical searches for eyepieces and useful accessories LEARN AT THE TELESCOPE Browse concise guides covering magnification, exit pupil, field of view, telescope types, aperture, seeing conditions, planetary observing, deep-sky observing, filters, Barlow lenses, equipment planning, beginner mistakes, and solar safety. The app stores your telescope, eyepiece, and calculation entries on your device. It does not require an account.