Open Planetarium vs Star Explorer

Open Planetarium is a beautiful, scientifically accurate virtual planetarium. The full sky works completely offline — all star, constellation, and deep-sky data is bundled with the app. FEATURES • Real star catalog: 8,920 stars down to magnitude 6.5 (HYG v4.1), with scientifically accurate star colors derived from each star's B-V color index • All 88 constellations: lines, names (English / Japanese / Latin), and official IAU boundaries • Solar system: the Sun, the Moon with phases and lunar age, and all 7 planets, computed with Meeus/Standish-compliant algorithms • Deep-sky objects: the complete Messier catalog (110 objects) plus major NGC/IC objects — 717 objects in total, with type icons • Powerful search: object names, constellations, M/NGC/IC numbers, planets • Object details: magnitude, coordinates, altitude/azimuth, and rise/transit/set times for your location • Time travel: set any date and time with the calendar dialog, scrub through the day with the time slider, or play diurnal motion at 60×/600×/3600× • Observing location: pick your spot on a zoomable world map with 1,250+ cities, search by country/city, enter coordinates manually, or use GPS • Survey imagery: overlay DSS2 sky survey layers (downloaded on demand and cached for offline re-display) • Equipment & field-of-view simulator: register telescopes, cameras, eyepieces and Barlows/reducers to preview framing and plan mosaic imaging • Milky Way rendering and adjustable light-pollution levels PRIVACY Your location is used only on your device to compute the sky above you — it is never sent anywhere. If location permission is denied, you can set the observing location manually. Open Planetarium is free, open source (MIT), with no ads and no tracking.

APPLE WATCH See the Moon phase, illuminated fraction and moonless observing window, browse astronomy events, and add watch widgets. Sky calculations run on device; weather requires a network connection. Point your iPhone at the night sky and instantly see what you're looking at. Star Explorer names stars, planets, constellations and the Moon in AR, and tells you what's worth seeing tonight from where you are. No sign-up needed to start. The star catalog, sky map and astronomy assistant work offline, so they keep working at dark-sky sites with no signal. WHAT YOU CAN DO - AR star finder: hold up your phone to identify stars, planets and constellations, with comet and meteor-shower layers - Night sky map: a live all-sky chart you can move forward or back in time; search 8,900+ stars, all 88 constellations and all 110 Messier objects - Tonight's sky: Moon phase, visible planets and observing conditions for your location and weather - Sky events: meteor showers, planet oppositions and every solar and lunar eclipse from 2027 to 2030, with reminders - Offline astronomy assistant: ask questions and get an observing plan without a connection - Red-light night mode that protects your night vision - Tonight's Sky widget for your Home Screen - Bite-size astronomy lessons with quizzes, and a stargazing trip planner - Made for iPhone and iPad, including the iPhone Duo inner display Free forever: AR star finder, sky map, sky events, offline assistant, lessons, night mode and widget. Optional purchases: - Pro, all features, lifetime: one-time purchase that unlocks the deep-sky catalog, astrophotography assistant, cloud AI and photo identification - Observing Tools, lifetime: one-time purchase that unlocks the deep-sky catalog and astrophotography assistant - Cloud AI monthly / yearly subscription: unlocks cloud AI answers and photo identification Auto-renewing subscriptions: the subscription period is 1 month or 1 year, and payment is charged to your Apple ID account when you confirm the purchase. The subscription renews automatically at the same price unless auto-renew is turned off at least 24 hours before the end of the current period. Manage or cancel any time in Settings > Apple ID > Subscriptions. The price shown on the App Store purchase confirmation is final. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://star.xinghebit.com/privacy/ Sky data, weather, travel routes and AI answers may contain errors and are not navigation, weather or safety guarantees. Check official sources before observing outdoors. Never look at the Sun through a camera, binoculars or telescope without a certified solar filter.