Stellarium Is the Free 'Planetarium' for Your Computer

A screenshot from Stellarium shows the planets Saturn, Jupiter and Mercury as they appear in the night sky. Wikimedia Commons (CC BY-SA 4.0)

There's nothing quite like seeing the expanse of the Milky Way stretching across the sky, or spotting one of those many cool recent comets or planetary conjunctions. Add in a telescope and you can truly unlock some incredible wonders in the night sky. However, most of us live in light polluted areas, and it's hard to really get to know what you're seeing among the stars on any given night.

That's where astronomy software comes in. Astronomy software helps you learn more about the night sky without needing to find a dark place or worry about cloudy skies. There are a number of options available, though most astronomers — both amateur and professional — tend toward one: Stellarium.


Whether you choose to learn how to use Stellarium or another astronomy software, you'll soon discover that what we can see with our eyes and telescopes from earth barely scratches the surface of our astronomy understanding. Be prepared to end up even more interested in stargazing after mastering astronomy software.

The Power of Astronomy Software

What makes astronomy software so powerful is the fact that it allows us to see simulations of real phenomena in the night sky. Whether you're curious about what you're seeing tonight from your location on Earth or want to learn more about one of those headline-grabbing astronomical events in the last few years, you can use astronomy software like Stellarium to quench your thirst for knowledge.

Stellarium is just one of several free astronomy software programs available; others include WorldWide Telescope (WWT), Aladin Sky Atlas and Home Planet. Each of these programs offers slightly different experiences: Some have different night sky maps, while others provide an easier-to-use (or more complex) user interface. Most people go with Stellarium, which is why it has become one of the most popular astronomy software programs out there.


Stargazing with Stellarium

When using astronomy software like Stellarium, there are a number of wondrous objects in the night sky that you can "see."

"Software like Stellarium lets you explore what's visible in the sky on any given night from any location, including stars, planets, galaxies, nebulae, asteroids, comets and even man-made satellites and the International Space Station," says Andrew Williamson, postdoctoral fellow at the Institute for Cosmology and Gravitation within the University of Portsmouth in England. Many of these objects may not be visible from your backyard due to light pollution, geographic location or other reasons — never mind that many are too far away to see without a high-powered consumer telescope.


And for those with telescopes, Stellarium and other astronomy software can serve as a guide to what you can see on your own: "For amateur astronomers that want to know what they can expect to see in their telescope, software can simulate this too. If you have a computerized telescope mount, some programs can even be used to control it," Williamson says.

That's not all you can see with Stellarium and other astronomy software though. "I've also used it to illustrate astronomy concepts such as retrograde motion and the effects of light pollution," Williamson continues. "This makes it a powerful tool for teaching yourself and others about why it's important to preserve dark sky places — and demystify attention-grabbing headlines about night sky events."


Is Stellarium Worth the Learning Curve?

If you're curious about astronomy software like Stellarium, you might wonder if it's worth the "learning curve" to figure out how the software works. Williamson has some thoughts on that too: "Everybody loves a good planetarium show, but if you want to explore the night sky at home from your phone or computer there are lots of options out there to suit everybody.

"If you've ever looked up at the sky and wondered what you were looking at, there are apps for your phone (including free ones like Stellarium) that you can quickly open and point up at the sky to find out," he continues.


And as to whether you should use Stellarium compared to other astronomy software, "Stellarium is particularly good because it's free to use, with mobile and web versions that make it easy for everyone to get started," Williamson says. "It also has more advanced features and downloadable plug-ins that make it customizable, so, for example, somebody who is into astrophotography can download telescope plug-ins that will help them plan and execute their observations."