Compare software

WorldWide TelescopeKStars
Free

Free and open source.

 Free

Free and open source from the KDE community.

Web Windows, macOS, Linux
  • Large collection of sky imagery in the browser
  • Guided tours with narration and slides
  • Sky simulation with up to 100 million stars, plus comets and asteroids
  • Observation planner and calculation tools such as conjunction prediction
  • Needs a fast internet connection
  • Interface can feel dense for newcomers
  • The large feature set takes time to learn
  • Some information and imagery features rely on internet resources
Web application Downloadable app
Open source Open source
License not stated License not stated
Not stated if an account is needed No account needed
Needs internet Not stated if it works offline

Checked October 2, 2026

Checked September 23, 2026

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