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.