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