Bellow installation procedure uses only command line approach, because this is the simpler way to follow instructions just by copy-pasting the commands in terminal. Instructions tested on Ubuntu 12.04, 11.10 and 11.04.
sudo apt-add-repository 'deb http://www.ap-i.net/apt stable main'
Note: If you would like to install development version of Skychart instead of stable version, then replace word “stable” with “unstable” in above and bellow command.
sudo apt-add-repository --remove 'deb-src http://www.ap-i.net/apt stable main'
gpg --keyserver keyserver.ubuntu.com --recv C56CCB02D79BF92A
gpg --export --armor C56CCB02D79BF92A | sudo apt-key add -
sudo apt-get update
sudo apt-get install --no-install-recommends skychart
sudo apt-get install skychart-data-stars skychart-data-dso skychart-data-pictures
skychart
You will also find the Skychart button in the main menu, using “Science & Engineering” filter.
Note: If installed following above instructions, 'skychart' command is actually a script that disables some Ubuntu Unity features (only for Skychart program) to make it possible Skychart to work correctly (LIBOVERLAY_SCROLLBAR=0 and UBUNTU_MENUPROXY=0).