Celestia vs ISS Detector

Celestia is free, open-source software for visualizing space in 3D. It simulates objects ranging from planets and moons to star clusters and galaxies, which can be viewed from different positions in space and at different times. Solar system positions and movements are calculated in real time, and users can choose the rate of motion. Celestia also works as a planetarium: users can travel to celestial worlds, land on their surfaces, and see solar system objects in the sky. Add-ons expand the catalogues with objects, high-resolution textures, 3D models, spacecraft, and fictional objects. Celestia is licensed under the GNU General Public License and is available for Android, iOS, Linux, macOS, web, and Windows. The browser option is a lite version. Installation routes differ: Android versions are offered through Google Play, GitHub APK, and alternative markets; Apple versions are on the App Store, with a direct GitHub download for macOS. Windows users can use the Microsoft Store or sideload a GitHub version. The latest stable original-project release for Linux is listed as source code.

ISS Detector helps users find visible International Space Station passes and predict satellite passes for their location. For each upcoming ISS pass, it gives the local start time, direction, highest altitude, and duration, and can notify users minutes before the pass begins. It checks the local forecast and indicates when clouds may prevent a sighting. Premium features add tracking for Starlink, Hubble, rocket bodies, planets, comets, and amateur radio satellites; amateur radio tracking includes transmitter information and Doppler shift calculations. Users can share sightings on social media. ISS Detector says it combines information from NASA, Heavens-Above, the Minor Planet Center, and yr.no weather. It is listed for Android, iOS, macOS, and web. The free plan includes ads and in-app purchases; ISS Detector Pro costs $17.99, paid once and includes all extensions with no ads. Its privacy policy says location calculations happen on-device and precise location is not stored on the maker’s servers. Google Play says data can’t be deleted.