Open Planetarium

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.