Each of them you can view in 3D, in realtime, in OpenGL.
Check out what is in each of them. Adjust the settings, change them.
OPTIONS :
+ Set Predefined Galaxies (11 avaiable now)
+ Set Background type (5 avaiable now)
+ Set Core type (3 avaiable now)
+ Set Stars type (3 avaiable now)
+ Set Stars count (for max speed reduce stars)
+ Set X-Ray type, on/off (default off)
+ Set Stars on/off