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Astronomy Apps

Free Astronomy Apps from Orange County Telescope

Find Messier objects, name every crater on the Moon, and get more out of every night at the eyepiece. Free to use, with optional one-time Pro unlocks.

BEST DEAL

MessierGenius Pro + Lunar CraterFinder Pro

Both Pro unlocks for $7.99 $9.98, so you save $1.99. One-time purchase, no subscription, no monthly fees.

Get both Pro unlocks: $7.99 one-time (save $1.99)
MessierGenius app: star map and Messier object finder

MessierGenius

Free:

  • Live sky map with FIND-mode arrows that point you to each object
  • All 110 Messier objects with real images
  • Messier Marathon checklist and fun-fact quizzes
  • Photo plate solving

Pro ($4.99, one-time):

  • Eyepiece mode: hold your phone to the eyepiece, and Pro matches the view against 55,000 fainter stars and labels what you're looking at
  • Night Sky Camera: 1–4 second exposures with manual ISO, focus locked at infinity, and frame stacking
Buy MessierGenius Pro: $4.99 one-timeLearn more / free download
Lunar CraterFinder app: live Moon map with crater names

Lunar CraterFinder

Free:

  • Live Moon map showing tonight's phase
  • Crater names across the Moon
  • Photo crater labeling for your own Moon photos

Pro ($4.99, one-time):

  • Image scale measured from your photo (arcseconds per pixel)
  • Field-of-view and magnification tools for your telescope and eyepiece
  • Tonight's seeing rating, compared with your scope's Dawes limit
Buy CraterFinder Pro: $4.99 one-timeLearn more
BEST DEAL

MessierGenius Pro + Lunar CraterFinder Pro

Both Pro unlocks for $7.99 $9.98, so you save $1.99. One-time purchase, no subscription, no monthly fees.

Get both Pro unlocks: $7.99 one-time (save $1.99)

For Android. The Google Play listing is coming soon. After you buy, your unlock code is emailed to you, and you enter it in the app. It works offline, and there's no subscription.

Need a telescope to use them?

Celestron NexStar SE and NexStar Evolution GoTo scopes find Messier objects and Moon craters for you. Ask our experts which one fits you.

Shop NexStar SEShop NexStar Evolution

Call 888-471-9991

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