What is Stellarium? The free planetarium app, explained for families
By the WhyCosmos team · Last updated:
Stellarium is a free, open-source planetarium for your computer or phone. It shows a realistic night sky exactly as it appears from your location, at any time — tonight, next week, or the night you were born. Type your city, and it becomes a map of your actual sky, letting a child identify planets and constellations before ever touching a telescope.
Stellarium has been developed openly since 2001, is used in real planetariums, and costs nothing. For Indian families it solves the biggest beginner problem in astronomy: standing under the sky and not knowing what anything is. Interest in it is growing — “stellarium” draws about 22,200 searches a month in India (Ubersuggest, 2026).
How to explain it to your child
Explain it to an 8-year-old
Stellarium is a magic sky map on a screen. You tell it your city, and it shows you exactly which stars and planets are above your house right now. Point at a bright dot and it tells you if it is Jupiter, Saturn or a star — like having name tags on the whole sky.
Explain it to a 13-year-old
Stellarium is open-source planetarium software that simulates the sky for any location, date and time, with a catalogue of hundreds of thousands of stars in the base version. You can fast-forward time to watch planets move, switch on constellation lines and deep-sky object labels, and use night mode to preserve dark-adapted vision during real observation sessions.
Key facts
| What it is | Free, open-source planetarium software |
|---|---|
| First released | 2001 — still actively developed |
| Cost | Free (no ads in the desktop and web versions) |
| Platforms | Windows, macOS, Linux, web browser, and mobile apps |
| Web version | stellarium-web.org — nothing to install |
| Best beginner features | Search any object, constellation lines, time travel, night (red) mode |
| Used by | Home stargazers, schools, astronomy clubs and real planetariums |
How can a child use Stellarium tonight? (5-step starter)
- Open stellarium-web.org in a browser and allow location, or set your city manually.
- In the search bar, type Saturn (or Jupiter). The sky swings around and an arrow points to it.
- Note the direction and height. Then go outside — or to a window facing that direction — and find the same bright dot in the real sky.
- Back in the app, click the object to read its facts: distance, brightness, and when it sets.
- Use the time controls to fast-forward to midnight, or to this date next month, and watch how the sky changes.
Why we recommend software before a telescope
A telescope shows your child one object at a time, if you can find it. Stellarium teaches the map — which is why WhyCosmos classes use planetarium software from week one, and why “how to use Stellarium” features in our lessons on navigating the sky. Once your child can walk outside and name three planets unaided, a telescope becomes a reward instead of a frustration.
Is Stellarium safe for kids?
Yes. The desktop and web versions are open-source, free and ad-free — no accounts, no chat, no purchases. It is one of the rare screen activities that reliably ends with a child asking to go outside.
Questions parents and kids ask
Yes. The desktop program and stellarium-web.org are free and open-source with no ads. Some mobile app versions are paid or have optional purchases, but the free versions cover everything a beginner needs.
Fully. Set any Indian city as your location and it shows your exact sky — it also marks Indian time correctly and works fine in a browser on an ordinary laptop or phone.
From around age 7–8 with a parent driving, and independently from about 10. The interface is visual: type a name, follow the arrow, look up.
The desktop version works offline after download; the web version needs internet. No telescope required — Stellarium is precisely the tool that makes the sky make sense before you buy one.
Your child asks questions like this every week.WhyCosmos runs live online astronomy classes for ages 8–16, taught by real astrophysicists — where questions like these are the curriculum.
Related terms in this glossary
Sources and further reading