Tool profile
Cartes du Ciel: cost, fit and limits
Cartes du Ciel (Sky Charts) is free sky charting software by Patrick Chevalley, released under the GNU General Public License, that draws star charts with planets, asteroids and comets for Linux, Windows and Mac OS X.
What to know first
Cartes du Ciel is free software under the GNU General Public License, with stable and beta downloads and release notes on the project wiki. The homepage lists a choice of catalogs, control over star and nebula colors and sizes, picture superposition, visibility conditions and coordinate grids. Questions go to a mailing list and bugs to a bug tracker. The pages read name no AI feature, and the author is Patrick Chevalley.
Cartes du Ciel at a glance
| Maker | Patrick Chevalley, Not stated on the vendor pages |
|---|---|
| Free plan | Yes |
| Entry price | Free |
| API access | No |
| Category | Best AI Astronomy Software in 2026, rank 12 of 13 |
| Website | ap-i.net/skychart |
Who Cartes du Ciel is best for
Chart-focused observers
Control over catalogs and the look of stars and nebulae suits people who print or study charts rather than flying through a 3D sky.
Imagers who overlay pictures
Superposition of pictures on sky charts helps compare a captured frame with the catalog position of an object. Such overlays are a quick sanity check on framing and identification.
Open source users
The GNU General Public License and published beta versions suit users who like to follow releases on the wiki. The wiki publishes release notes and beta versions for those who want them.
Cartes du Ciel plans and pricing
| Plan | Price | What it includes |
|---|---|---|
| Cartes du Ciel | Free | Free software under the GNU General Public License, with stable and beta downloads and release notes on the wiki. |
Checked November 2026.
What Cartes du Ciel does
- Solar system objects
- The chart draws the positions of planets, asteroids and comets, which helps with planning around moving targets. That helps when planning around moving targets that change position night to night.
- Catalog choice
- Users select catalogs and set the color and size of stars and nebulae. Choosing which catalogs to display also keeps a chart readable at wide fields.
- Picture overlay
- Pictures can be superimposed on the sky chart for comparison. This lets you check a captured frame against the catalog position of the same field.
- Visibility and grids
- Visibility conditions and coordinate grids appear on the chart. The grids help with finding objects and reading their positions on the chart. They also help read where an object sits on the sky.
- Platforms
- The homepage lists Linux, Windows and Mac OS X builds. Those platforms cover most desktop operating systems used by hobbyists. That covers the usual desktop systems of hobby observers.
How Cartes du Ciel handles your data
The Cartes du Ciel pages we read do not describe data collection, retention, hosting region or certifications, and nothing says whether any data trains AI models. The contact page names Patrick Chevalley as the project author and directs questions to a mailing list and bugs to a bug tracker, both of which are public channels. Cartes du Ciel is installed on your own computer and is open source, so what it does with your files can be checked in the code, though the vendor's policy was not checked.
Where Cartes du Ciel falls short in practice
- Charting only. The pages read describe sky charts, not camera or mount automation, so imaging needs a capture suite beside it. Imaging needs a capture suite beside it, such as N.I.N.A. or APT.
- Older Windows limits. Version 3 has limitations on Windows 95, 98 and Me, and version 2.76 is Windows only and no longer maintained. That matters mainly for owners of very old machines.
- Community support. Questions go to a mailing list and bugs to the bug tracker, and no paid support is stated. Expect replies from the author and other users, not a service desk.
Alternatives to Cartes du Ciel
Cartes du Ciel: common questions
Is Cartes du Ciel free?
Yes. The homepage and contact page describe it as free software released under the GNU General Public License, with stable and beta downloads. No paid tier appears on the pages we read, and support runs through a mailing list and a bug tracker.
Which systems does Cartes du Ciel run on?
The homepage lists Linux, Windows and Mac OS X. It adds that version 3 has limitations on Windows 95, 98 and Me, and that version 2.76 is Windows only and no longer maintained, so older machines should check the notes.
Does Cartes du Ciel use AI?
The pages we read name no AI feature. The program is described as software that draws sky charts with planets, asteroids and comets, with catalog choices and picture superposition. Voyager and StellarMate are the entries in this list that name AI.
Can Cartes du Ciel overlay my photos?
Yes. The homepage lists superposition of pictures on sky charts. That lets you compare a captured frame with the chart for the same field, which helps identify objects, though the pages read give no detail on file formats. The pages read give no detail on file formats.
Where do I report a bug in Cartes du Ciel?
The contact page says bugs go to the bug tracker and questions to a mailing list. Release notes and beta versions are published on the wiki. No paid support is stated, so expect community and author replies. Replies come from the community.