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Sky Map vs Cartes du Ciel (SkyChart): catalog facts
Sky Map	Cartes du Ciel (SkyChart)
Free Free and open source under the GPL 3.0 or later licence.	Free Free software under the GPL.
Android	Windows, macOS, Linux
Real-time identification using the phone's sensors Long history, maintained by the original developers	Uses many star and deep-sky catalogues Shows planets, asteroids and comets
The classic interface looks dated, as the developers acknowledge Accuracy depends on the phone's compass and sensors	The number of settings can overwhelm casual stargazers Interface is functional rather than polished
Downloadable app	Downloadable app
Open source	Open source
License: GPL-3.0-or-later	License: GPL
No account needed	No account needed
Not stated if it works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.