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Every once in a while when I am speaking with other astronomy instructors, I’m asked if I know of any resources that would work well for supplementing labs. Many of these instructors don’t have access to an observatory or a planetarium, or they teach distance learning courses. An increasingly popular solution is to create labs where students use some form of planetarium based software.

Planetarium based software gives you, the instructor, possibilities for labs that are only limited to your imagination, and it gives students the ability to immerse themselves in the sky, even with their busy schedules.

Currently, my planetarium based software of choice is Stellarium. I favor it because the user interface is simple and easy to learn, and best of all, it’s free. It works on Windows, Mac, and even Linux, and it’s not one of those clunky open source programs that developers abandon; it was created in 2001 and has been updated as recently as July 2014. Stellarium has quality graphics that are rendered in real time using OpenGL. They even have a mobile app that can run on tablets.

Features of Stellarium

Stellarium utilizes a wide range of data for over 600,000 stars from both the Hipparcos and Tycho-2 catalogues. It has also compiled data from other catalogues to include over 210 million stars. In addition, it incorporates coordinates and images for both the Messier and NGC catalogues.

Students can interact with the universe and gather data by panning, zooming, and selecting objects in the sky. They can also select specific dates and speed up or reverse time from any given location. This can enhance their comprehension of the motions of heavens, i.e. diurnal motion, retrograde motion, circumpolar region, moons’ motion against the background stars, and even precession.

Currently, I’m learning how Stellarium can be used as planetarium projection system. It can do distortions for fisheye, stereographic, and spherical mirror projection.

You can find a full list of features here. If you would like a thorough tutorial of Stellarium, TheFrugalComputerGuy on YouTube has put together a good 3 part tutorial series (1, 2, 3).

How to use Stellarium in your astronomy course

In the online astronomy courses I teach, Stellarium is incorporated into several labs. For example, our Stars and Constellations lab uses Stellarium to teach students how to navigate the sky. We ask them to explore the constellations that are out during at different times of the year, as well as the circumpolar region. They learn about visual magnitudes of stars, do exercises to determine if they would be able to see a particular star or object, and perform distance calculations that can be checked with Stellarium. They also learn how to use different stellar coordinates in this lab.

In many large astronomy programs, lab space and availability are limited and it can be impossible to coordinate a make-up for a missed lab or a one due to a cloudy night. To combat this issue, I designed a cloudy night lab program at UNT. I adjusted each of our observatory labs so they could be completed with planetarium based software to maintain learning outcomes. Here is an example of one of my cloudy night labs.

There are endless possibilities for labs you can create with Stellarium. If you want a head start, a quick Google search will yield a lot of interesting results, as many instructors have already created quality labs. Some indicate you are free to use them in your course, but others require permission from the creator. Either way, pre-existing labs can give you some great ideas. You can also check out education resources provided by Stellarium’s Wiki.

Even if you already have your labs covered, Stellarium can also be used to enhance them. When I was teaching labs at UNT’s observatory, we used a similar planetarium based software, TheSky6 (now TheSkyX), to give students an idea of which stars, constellations, and planets were out and where they would be located in the sky. We also used this system for telescope control on some of our larger telescopes. When calibrated correctly, you can click the object on the computer screen and watch the telescope guide itself to the object.  This is especially nice for outreach events. Stellarium’s telescope control feature and can also be used for these purposes.

Before launching Stellarium in your course, it’s recommended to create modulated videos to demonstrate how to use the software and complete all exercises. In my experience, students tend to engage more when given video instructions versus written out ones (read is a four letter word these days, as one of my colleagues says). Specifically, screen recordings get the point across much faster.


Student Reception

At the end of each semester, I ask students to evaluate our labs. The majority always favors the Stellarium Labs. In several cases, I have had students share that they open it up to play around when they have free time. Sometimes I’ll run into former students who still dabble with Stellarium on occasion. They seem to enjoy freely exploring an open world, similar to many popular video games.



If you have any other questions or even suggestions you would like to share on this topic, please do so below in the comment section. If you are interested in some of the labs we offer that utilize Stellarium or any other lab ideas I have for planetarium based software, please feel free to reach out to me by email at



“Solstice Winter (Southern Hemisphere) - Stellarium” image by Marco Antonio from flickr under the Attribution 2.0 Generic Creative Commons license.

“Giving a lecture with Stellarium” image by Erik Newth from under the Attribution 2.0 Generic Creative Commons license.