In this article I will show you two open-source planetarium/stargazing pieces of software: Stellarium and Celestia.
Stellarium is an open-source planetarium application, providing a realistic and accurate sky image in 3D, as if the users were looking through a telescope.
To install Stellarium on Ubuntu, do:
$ sudo add-apt-repository ppa:stellarium/stellarium-releases
$ sudo apt-get update
$ sudo apt-get install stellarium
Celestia is yet another open-source planetarium app, created by Chris Laurel. The app is based on Hipparcos Catalogue (HIP) and permits the users to travel through space.
To install Celestia on Ubuntu, do:
$ sudo apt-get update
$ sudo apt-get install celestia
The installation instructions should work on Ubuntu 15.04 Vivid Vervet, Ubuntu 14.04 Trusty Tahr, Ubuntu 12.04 Precise Pangolin and derivative systems like Linux Mint 17.2 Rafaela, Linux Mint 17.1 Rebecca, Linux Mint 17 Qiana, Linux Mint 13 Maya, Pinguy OS 14.04, Elementary OS 0.3 Freya, Elementary OS 0.2 Luna, Deepin 2014, Peppermint 6, Peppermint 5, LXLE 14.04 and Linux Lite 2.