Cosmonium is an open source 3D astronomy and space exploration software

Star gazing can be a relaxing experience, and you don’t need telescopes or planetariums to learn more about the mysteries of Space. You can explore galaxies that are far, far away, right from the comfort of your house.

No, I’m not talking about movies and TV Shows. Welcome to Cosmonium, an open source 3D astronomy and space exploration software. It is based on the (now defunct) Celestia project.

Cosmonium default graphics

Cosmonium is a chunky download at a little over 280MB and takes up about 527MB of space to install. You will need a graphics card that supports OpenGL 2.1+. If your computer can handle it, and if you the storage space to spare, you can try the HD and UHD textures. The textures weigh about 1.8GB each to download. I used the default textures that came with the program.

Cosmonium start screen

The program’s installation is pretty straight-forward. When you run it, Cosmonium presents a view of the Earth. It displays the parameters of the selected celestial object such as the name, altitude, radius, in the top left corner, while the frame rate is displayed on the opposite edge of the window.

Left-click on a planet or star to select it, double-click centers the view to the selected object. Pan the camera by holding the mouse button and dragging it in the direction you want. Use the mouse wheel to zoom in and out.

Cosmonium zoom

Let’s get back to Earth, shall we? Right-click on the planet and drag to rotate the view.

Cosmonium uses the current time to display the day/night view of the earth, i.e. the side of the earth that is away from the sun will appear dark. And yes, you can rotate it in a 360° view and this also works with the galactic view.

Cosmonium rotate view

Speaking of time, click on the Time menu to increase, decrease, reverse, freeze the time, or set the time manually or use the current time.

Cosmonium travel

Can we view other planets and stars? Of course, hit Enter and search for the object, e.g. Mars. Hit Enter again and its stats appears in the top left corner, tap the G key to jump to the planet. This includes a nice travelling animation which pans and zooms onto the object.

Cosmonium right-click menu

Right-click on an object to view a menu that includes among other options, an info panel.

Cosmonium info panel

There are many keyboard shortcuts available in Cosmonium, you can access the list by using Shift + F1. E.g. Ctrl + M toggles the menu bar, V hides the HUD. Most of the options are also available in the various menus.  The Render menu lets you toggle labels, orbits, bodies, grids, guides, 3D rendering and more. Switch to full screen mode using Alt + Enter or from the Window menu.  The program has an option to save screenshots, but it doesn’t seem to work.

Cosmonium is an open source application, it is written in Python. The program is available for Linux, macOS and Windows. You can change the graphics settings from the File menu > Preferences > Advanced screen. To learn more about the advanced options, refer to the project’s wiki. The application is still in beta. It crashed a few times in full screen mode. Hopefully it will get better with updates.

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