Sky Map (formerly Google Sky Map, open sourced in 2012)
1.7k
Stars
273
Forks
123
Open issues
30
Contributors
AI Analysis
Sky Map is an open-source Android astronomy app that displays stars, constellations, planets, and celestial objects in real-time by aligning with device orientation. Originally Google Sky Map (launched 2009), it is now community-maintained and best serves casual stargazers and astronomy enthusiasts who want a lightweight, ad-free mobile planetarium—not professional astronomers or those needing advanced observational tools.
Inferred from signals mentioned in the README (tests, CI, type safety) — not a review of the actual code.
AI's overall editorial judgment — not an average of the bars above, can weigh other factors too.
Legacy Android astronomy app, open-sourced from Google, maintained by original developers as volunteer effort
Sky Map is an open-source Android astronomy application with roots in Google's original 2009 release. Now maintained by ex-Google developers as a personal project, it provides real-time star-gazing features via device orientation sensors. Distribution spans Google Play and F-Droid. The project occupies a specific niche: users seeking ad-free, privacy-respecting celestial navigation without complex features. Adoption appears modest but stable, with active maintenance evidenced by recent commits and ongoing modernization efforts.
Launched as Google Sky Map on the first Android phone in 2009. Google ceased active support in 2011 and open-sourced the application with permission. Original developers have maintained it since, initially as personal projects under Google's oversight, now independently as Penterakt LLC while retaining the core team and mission.
The project gained 1,740 stars over its lifetime on GitHub (created 2015 as a repository, though the app predates this by 6 years). Growth appears steady but modest—7 stars in the last 7 days suggests a consistent but slow accumulation of interest. No viral adoption or sudden spikes are evident. Stability and maintenance continuity, rather than explosive growth, characterize the trajectory.
Sky Map is distributed on Google Play Store and F-Droid, indicating established production deployment channels. The README states 'Sky Map has a long history' and references continued use by a community that 'still find[s] joy in its simplicity.' However, concrete user numbers, download statistics, or production incident logs are not provided in the README. Adoption not formally verified beyond distribution availability.
Based on README, the project began in 2009 and has undergone significant rewriting since Google's era. Architecture appears to reflect legacy Android patterns. The README explicitly acknowledges that 'while most of the code has been rewritten since its Google days, the architecture reflects its origins.' A complete modernization effort is underway. Codebase is written in Kotlin (as of the repository snapshot), suggesting partial migration from Java. The presence of both GPLv3 and Apache 2.0 licensing indicates a hybrid legacy codebase.
Not documented in README. No mention of testing framework, test coverage metrics, or CI/CD practices beyond a Travis CI badge reference.
Last push: 2026-07-04 (2 days before analysis date). This indicates active, recent development. Commit frequency cannot be fully assessed from metadata alone, but the recency strongly suggests the project is not dormant. README explicitly states 'we are continually inspired by the community' and mentions 'we are currently working on a complete modernization of the app,' implying ongoing active work.
ADOPT IF: you are an Android user seeking a simple, ad-free, privacy-respecting star map with no complex features, and you value the heritage and transparency of an app maintained by its original creators. AVOID IF: you require extensive feature depth, active user community forums, comprehensive documentation, or guaranteed long-term corporate backing. MONITOR IF: you are considering contributing or interested in how legacy-codebase modernization evolves; the ongoing architectural refresh may produce insights applicable to similar projects.
Independent dimensions
Mainstream potential
2/10
Technical importance
4/10
Adoption evidence
3/10
- Modernization effort is in progress but timeline and scope are unclear. Architecture acknowledged as legacy may limit feature velocity.
- Maintenance depends on volunteer effort by a small number of ex-Googlers. Sustainability beyond current maintainers is not documented.
- User base and adoption metrics are not publicly disclosed; market size and growth potential cannot be independently verified.
- Android API evolution and device capability changes over time may create compatibility challenges; slow update cadence relative to platform evolution could cause drift.
- Licensing complexity (GPLv3 + Apache 2.0 hybrid) may deter some contributors or reusers; clone-prevention measures in licensing may reduce community forks.
Sky Map will likely remain a stable, niche utility for privacy-conscious stargazers on Android. Modernization efforts may improve developer experience and feature velocity, but mainstream growth is unlikely given the narrowness of the use case and competition from larger, feature-rich alternatives. Project will probably persist as a volunteer-maintained service rather than transition to commercial or significantly accelerated development.
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Languages
Information
- Language
- Kotlin
- License
- GPL-3.0
- Last updated
- 1d ago
- Created
- 135mo ago
- Analyzed with
- anthropic/claude-haiku-4-5
Stars over time
Contributors over time
Top 100 contributors only — repos with more will plateau at 100.
Open issues
Sky Location of Moon and near-earth objects should factor in user's location on earth.
Update dependencies
Create a system-wide color palette
The icons need a refresh
Messier objects in the gallery are not sorted naturally
Top contributors
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Stellarium is a desktop and mobile planetarium with significantly larger community and feature set. Sky Map targets lightweight, orientation-sensor-based mobile stargazing; Stellarium targets comprehensive astronomical simulation on multiple platforms. Different use cases rather than direct replacement.
SkyTube is a privacy-respecting video client. Not a direct competitor; operates in a different category. No meaningful comparison.
StreetComplete is a mapping/crowd-sourcing Android app written in Kotlin. Shares language but serves a different problem domain. No meaningful competitive relationship.
Sky Map
