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 locally on your device. It does not require an account.