A planetarium is probably the best choice to learn about astronomy in a way that is both fun and educational at the same time. Yet if you have no access to a planetarium where you live, you can have it on your computer with Stellarium, a free and open source, cross-platform planetarium software available for all major operating systems, including Linux.
Learning about the stars from the comfort of your chair
Stellarium offers a very detailed map of the night sky. You can set your location and any point of time, even in the past or the future, to see what the sky looked, looks, or will look like from anywhere on or off the planet. According to their website, Stellarium offers
Default catalogue of over 600,000 stars Extra catalogues with more than 210 million stars Asterisms and illustrations of the constellations Constellations for 20+ different cultures Images of nebulae (full Messier catalogue) Realistic Milky Way Very realistic atmosphere, sunrise and sunset The planets and their satellites
It also offers powerful controls such as seamless zooming, different projection modes with detailed explanations, and many more advanced features. For an enhanced viewing experience, Stellarium can toggle equatorial and azimuthal grids, star twinkling, shooting stars, eclipse simulation, and supernovae simulation. You can choose from preset skins for your viewing locations or use your own landscape skins if you like. You can extend Stellarium with plug-ins or from online resources and even add your own constellations.
Basic usage
Stellarium will start up showing the sky at your current location (if available) at the current time of day with the default landscape. So if you are using it during the daytime hours you might not get to see much at first.
If you bring your mouse to the lower left part of the screen, a menu will pop up that will allow you to turn off the atmosphere (1) and the ground (2), toggle constellations’ lines and labels (3), artwork (4), and various gridlines (5)
Turning the atmosphere off …
… and the constellations on …
… will present you with a more enjoyable view. If you also turn off the ground, you will get a full view as if you would be able to see thorugh the Earth:
The other bottom left menu (press your mouse to the left edge) will present you with different configuration options such as the date and time (1), location (2), sky and viewing points (3), search window (4) and configuration window (5) menus.
Most of these are self-explanatory. The really interesting ones are “Sky and viewing points” that will let you change, besides the basic appearance, the projection type …
… and the culture through the eyes of which the constellations are shown.
The configuration window will let you fine tune and extend Stellarium with various plugins.
Constellations from different cultures
A really nice feature of the software is its database of constellations from over twenty different cultures from all over the planet to explore how these people have seen or see the night sky. On the image below you can see the star-lore of the Boorong family of North-Western Australia.
Of course to meaningfully explore the sky, you should set the viewing location to coincide with that of those cultures geographically, and probably even the viewing time, if there is a great time difference, to see exactly how far away ancient people might have observed the stars.
The sky, as seen from different planets
Stellarium’s views are not limited to the surface of the Earth. You can choose from many planets, asteroids and comets in our Solar System. You can leave the atmosphere on to have a real feel of what it would be like to stand on the given planet. Surface skins are of course limited to those planets we have actual pictures of such as Mars, as seen on the image below, and simulations of the gas surface (top of the atmosphere) of gas giants like Jupiter.
Only the planetary surfaces are simulated. For different astronomical bodies you would have to make do with a plain horizon (or no horizon) if you choose to explore the sky from those viewponts.
Getting Stellarium
Installing Stellarium in Ubuntu and derivatives is easy via the official PPA. Just add the repository, update your package list, and install Stellarium: For the best performance it is recommended that you have a 3D capable video card with OpenGL 3.3 or greater and at least 1GB RAM. Neither of which should be a problem unless you have a really old computer. For downloads and installation instructions on different systems, visit the official Stellarium website.
Conclusion
Linux is an excellent platform for educational purposes. Be it math, physics or geometry, there is plenty of free software available. Stellarium is probably the brightest example of how a free and open source educational software can shine through, like so many stars, making the learning experience both fun and immersive.
