# Open Planetarium

> Lightweight planetarium app

Canonical page: [https://chrome-stats.com/d/id6799616519](https://chrome-stats.com/d/id6799616519)

## Overview

- **ID:** `id6799616519`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** CatsAI Agency
- **Category:** Education
- **Version:** 0.2.0
- **Last updated:** 2026-08-18
- **First published:** 2026-08-18
- **Size:** 26 MB
- **Data as of:** 2026-09-21
- **Store listing:** [Apple App Store](https://apps.apple.com/us/app/open-planetarium/id6799616519)
- **Website:** [https://github.com/kenyasue/OpenPlanetarium](https://github.com/kenyasue/OpenPlanetarium)
- **Privacy policy:** [https://catsai.agency/privacypolicy](https://catsai.agency/privacypolicy)

## Description

See the real night sky anywhere — no connection needed. Stars, planets, Messier objects, telescope FOV simulation, and a world-map location picker.

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.

## Rankings

- #1,399,476 — Overall

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Source: [Chrome-Stats](https://chrome-stats.com/d/id6799616519)