Polaris Sky Trainer

Learn the night sky. Master the constellations. Train like an astronomy Olympiad competitor.

Polaris Sky Trainer is a free astronomy learning app that combines an interactive planetarium with dedicated observation-training tools. Whether you're preparing for the International Olympiad on Astronomy and Astrophysics (IOAA), a national astronomy olympiad, or simply want to explore the stars, Polaris helps you learn the sky through hands-on practice.

EXPLORE THE NIGHT SKY
Explore a fully interactive planetarium from anywhere on Earth, at any date and time. Discover constellations, stars, planets, the Milky Way, and Messier objects. Toggle celestial coordinate grids, measure angular distances with a built-in ruler, and bookmark celestial objects to study later.

LEARN THROUGH INTERACTIVE PRACTICE
Go beyond simply looking at the sky. Train with dedicated practice modes to identify constellations, trace their figures from unlabeled stars, memorize Bayer designations (α, β, γ…), and locate Messier objects. Receive instant feedback and improve with every session.

STUDY SMARTER, NOT HARDER
Polaris uses spaced repetition to track what you're learning and automatically prioritize material you're struggling with or about to forget. Spend less time reviewing what you already know and more time mastering what you don't.

GENERATE PRINTABLE STAR CHARTS
Create customized star charts for any location, date, and time, complete with blank practice sheets and answer keys. Print them out and practice by hand, just like in a real astronomy olympiad observation round.

YOUR PERSONAL ASTRONOMY LIBRARY
Explore all 88 constellations, named stars, Messier objects, and asterisms in one comprehensive reference library, complete with helpful memory tricks to make learning easier.

TRACK YOUR PROGRESS
Earn XP, build daily streaks, unlock achievements, and visualize your progress through a constellation mastery map. You can also export and import your learning progress to back it up or transfer it between devices.

FREE, OFFLINE, AND PRIVATE
Polaris is built to make astronomy education accessible to everyone:
• Completely free, with no subscriptions or paywalls
• No ads or account required
• Works fully offline
• Your learning progress stays on your device

Explore the sky. Practice what matters. Make the stars familiar.

Recent changes:
First release of Polaris Sky Trainer.