What Is Stellarium and What Can You Do With It?

Updated

Stellarium is a free, open-source planetarium for your computer. It renders a realistic 3D sky that shows what you would see with the naked eye, binoculars, or a telescope — stars, planets, constellations, the Milky Way, and more. You'd use it if you want to explore or simulate the night sky, plan observing sessions, control a telescope, or run sky presentations and dome projections. It's a desktop application, and the project describes it as easy to use.

What Stellarium actually simulates

The core idea is a physically modeled sky rather than a static star map. According to the project, Stellarium shows a realistic sky in 3D, including:

  • A default catalogue of over 600,000 stars, with extra catalogues adding more than 220 million stars
  • A default catalogue of over 80,000 deep-sky objects, plus an extra catalogue with more than 1 million
  • The planets and their satellites, with orbital movement modeled
  • A realistic Milky Way, atmosphere, sunrise, and sunset
  • Asterisms and illustrations of constellations, with constellation sets for 40+ different cultures
  • Calendars from 35+ different cultures
  • Images of nebulae covering the full Messier catalogue
  • Full 6D astrometry for bright stars and movement modeling for various binary stars
  • All-sky surveys (DSS, HiPS)

It also simulates transient and dynamic events: star twinkling, shooting stars, comet tails, eclipses, supernovae and novae, and exoplanet locations.

How you interact with it

Stellarium is built around a graphical interface with extensive keyboard control, plus a powerful zoom and time control. Time control is the feature that separates it from a printed chart — you can jump to a date and watch the sky change, or speed up motion to see how the planets move over weeks.

Other interface and control features listed by the project:

  • A multilingual interface
  • A scripting interface for automating or reproducing specific views
  • An HTTP interface for web-based and remote control
  • Telescope control
  • Several coordinate grids and precession circles
  • Ocular (eyepiece) view simulation, so you can preview what a given eyepiece and telescope combination would show
  • 3D sceneries and skinnable landscapes with spheric panorama projection

For example, if you want to know whether Jupiter is above the horizon at 9 p.m. next Friday from your location, you set the date and time, and Stellarium draws the sky for that moment. Pressing N brings up nebula labels, as shown in the project's own screenshots.

Customization and extension

Stellarium is designed to be extended rather than used as-is only:

  • A plugin system adds artificial satellites, ocular simulation, telescope control, and more
  • You can add new solar system objects from online resources
  • You can add your own deep-sky objects, landscapes, constellation images, and scripts
  • Skinnable landscapes support spheric panorama projection

This matters if you want a specific site horizon, a custom object list, or a repeatable scripted tour rather than the default view.

Where it fits beyond a personal desktop

Two projection modes make Stellarium usable outside a single monitor:

  • Fisheye projection for planetarium domes
  • Spheric mirror projection for your own low-cost dome

Combined with the scripting and HTTP interfaces, this is why the software is used for presentations and dome shows, not just personal stargazing. The project's own presentation record reflects academic use as well — for instance, G. Zotti gave a talk titled "Virtual Archaeoastronomy and Simulation with Stellarium" at the University of Melbourne's Cultural Astronomy Graduate Seminar on November 14, 2025, and an extended presentation on desktop simulation of past and present skies at the ISAAC Oxford XIII/IAU Symposium 399 on July 3, 2025.

What to check before you commit

  • Platform: Stellarium is described as a planetarium for your computer, so plan on a desktop install rather than a browser-only tool. The project's feature list does not specify which operating systems are supported, so confirm that on the download page for your OS.
  • Hardware: The extra catalogues (220+ million stars, 1+ million deep-sky objects) and all-sky surveys are large; decide whether you need them or are fine with the default catalogues.
  • Dome or presentation use: If you need fisheye or spheric mirror projection, verify your projector and dome setup against those modes before building a workflow around them.
  • Cost and licensing: The project describes Stellarium as free and open source. The available page material does not list prices or paid tiers, so treat any commercial add-on or service you encounter separately from the core software.

If your goal is simply to see what the sky looks like tonight from where you are, the default install covers it. If your goal is a scripted dome show or a telescope-linked session, the scripting, HTTP, and telescope-control features are the ones to evaluate first.