If you have enjoyed Stellarium, the free planetarium software for your desktop, you will love Celestia. While Stellarium let you explore the sky from the bodies of different planets, Celestia reverses the viewpoint and will allow you to discover the stars and planets of a considerable chunk of the Universe with very detailed images of anything found within the boundaries of our solar system.
Most Linux distros will have a package for Celestia in the standard repositories. To install it just type
sudo apt-get install celestia
on a Debian-based system. If you want more textures you will have to manually install some non-free packages, as some of the texture files have unclear licenses and could not be included in the standard packages, which have a free license.
You can get the additional textures with
sudo apt-get install celestia-common-nonfree
although you might need to enable non-free repositories first, depending on your setup. To install everything at once, use
sudo apt-get install celestia celestia-common-nonfree
When you start the program, it greets you with a splash screen which disappears quickly, as the software loads literally in seconds (which justifies the name “splash” screen).
First it centers on the Sun and then on the Earth, where it will remain, waiting for you to interact with the virtual space.
For basic navigation, you can just use the mouse. Dragging with the left button will move your POV (point of view) on a flat plane, while dragging with the right button lets you turn the selected object around. To navigate to other celestial bodies you can use the navigation menu or certain keyboard shortcuts.
The most interesting navigation options are “Tour guide,”,“Start finder” and “Solar system browser.”
The tour guide will let you navigate to a few celestial objects, even outside of the solar system, while providing some basic information about the object selected.
Star browser will allow you to navigate to other stars.
If you select the radio button “With Planets,” it will limit your choices to stars with known orbiters, in which case you can use the “Solar System Browser” to find any planet in the given solar system, even outside of our own. Let us go to the star “IL ARQ”. Space travel is smooth, the animations are seamless and you can skim through light years in mere seconds.
It seems to have four orbiters.
Navigating to any of them will bring you closer and let you explore. Let us explore planet “e.”
To return to our solar system is easiest by pressing
h that will select our Sun. Pressing
g will then “Go to” the selection. The Solar System Browser will then be populated with many planets, moons and even manmade objects, which could be thoroughly explored.
You do not need to go far from home for amazing views
although traveling a little further also has its own advantages.
Sometimes the farther the better.
Time is set to real time by default, local to the user, so everything you see is exactly how it appears IRL. Time can be handled by speeding it up or slowing it down, or even reversing it, and you can set any given time and date you like.
Most of the various settings that are available in the options menu are also easily accessible from the “View Options” window.
Turning on various lines and labels will provide you with plenty of additional information.
Celestia offers split views, both horizontally and vertically, that will allow you to discover different locations at once or set different viewpoints for the same object.
Celestia can be extended by scripts, many of which can be found at the Celestia Motherlode website. Scripts can be added via the File menu. Scripting tutorials also exist, if you fancy writing your own. The File menu also offers functions to take screen-shots, record movies, or navigate the virtual space with “cel:// URLs.”
Celestia is a great free application that lets you discover the “closest” parts of the known universe in a fun and educational way that is also quite spectacular. With a huge database of stars, planets, comets and asteroids, with great looking texture maps for the celestial bodies’ smooth animations and plenty of customization options, Celestia offers hours, if not days, of exploring and learning.