# CelestiaProject/Celestia

Real-time 3D visualization of space.

Repository: https://github.com/CelestiaProject/Celestia
Canonical: https://ross.abutalabs.com/products/celestia
Homepage: https://celestiaproject.space
Language: C++
License: GPL-2.0
License Family: copyleft
Topics: celestia, astronomy, planetarium, educational, free-software, open-source, opengl, opengl-es, space
Last push: 2026-08-22T20:01:38+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 8, longevity 100
- inputs: {"age_days": 3598, "days_push": 11, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2351, forks 357 (observed 2026-08-28T04:06:40.325221+00:00)

## What it is
Celestia is a free, open-source real-time 3D space simulation that lets users explore the universe, traveling seamlessly from galaxy clusters down to individual spacecraft. It functions as an interactive planetarium with an expandable catalog of stars, planets, moons, asteroids, comets, and spacecraft, rendered accurately in real time.

## Use cases
- explore the solar system and 100,000+ stars in 3D
- use a planetarium that isn't confined to Earth's surface
- view accurate real-time positions of planets and moons
- teach astronomy with an interactive educational tool
- land on any celestial body and observe the sky from its surface
- extend the simulation with community add-ons and custom objects
- zoom seamlessly across scales from galaxies to spacecraft

## When to choose
- you want a free, cross-platform 3D space simulator rather than a ground-based planetarium
- you need accurate, real-time celestial positions for education or outreach
- you want an expandable platform with add-ons for custom celestial objects and spacecraft

## When to avoid
- you need professional telescope control or observational planning features
- you require photorealistic, game-grade graphics rather than scientific visualization
- you need a lightweight mobile-only stargazing app with AR sky views

## Facets
- artifact type: application
- maturity: active
- function: simulation, graphics, gui, data-visualization
- domain: astronomy, simulation, education, graphics, cross-platform
- platform: windows, cross-platform, cpp
- tags: planetarium, space-simulation, 3d-visualization, astronomy, opengl, educational-software, real-time-rendering, linux, macos, android, ios

## Member repositories
- CelestiaProject/Celestia (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:40.325221+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:36:53.602374+00:00, confidence not recorded.
  - readme: https://github.com/CelestiaProject/Celestia (fetched 2026-08-28T04:06:40.325221+00:00, sha a2f05e05013b)
  - homepage: https://celestiaproject.space (fetched 2026-08-29T10:17:19.151928+00:00, sha 7259db7638c8)
  - site_page: https://celestiaproject.space/faq.html (fetched 2026-08-29T10:17:19.161402+00:00, sha c297784d29af)
- Data as of 2026-08-30T08:39:29.467469+00:00.