Stellarium is described as
Stellarium is a free open source planetarium for your computer
Stellarium is an excellent companion for the hobbyist and the curious astronomer. It has an attractive interface that is at the same time educational. Stellarium provides a view of the sky similar to the one that would visible to the naked eye at any given time.
The program has two slide-in menus at the bottom and left hand corners of its interface and they offer tabbed menus that control a multitude of settings and features. The list of features is extensive and Stellarium is really a program that requires its multi-page *.pdf userguide. Setting a location is probably the first option to use as this will show the sky as it looks where you are. Location is set via the left hand slide-in menu and it is also possible to view the sky as it is in other locations and then of course to set one’s own as default. Mouse dragging is used to move around the sky. Mouse wheel zooms in and out. Time control, in the bottom slide-in menu, shows the position and movement of stars and planets in the past and future, in varying speeds.
The Sky and viewing options window has many choices for the landscape or ground that will be the program’s setting. It is possible to set if planets are shown, how much the stars twinkle, if an atmosphere is shown and even how much light pollution there is. There are numerous paragraphs and text on the history of astronomy in the Starlore tab.
The Search window (also invoked by pressing the F3 button) searches the extensive list of stars and planets in its database that includes the likes of the Hipparcos Catalogue.
The Configuration window is the place to play around with the system time, download more star catalogues and to try out scripts. Script support is limited as of this post (version 0.10.2) but more is promised.
The bottom slide-in menu offers the tools that would be most used when running Stellarium. Beside the aforementioned ability to move time faster to track star and planet movements here one can switch to full screen mode and night (red colored screen to preserve night vision) mode. Centering the highlighted or chosen star on screen and switching between equatorial and azimuthal mounts are two other useful options. Toggling planet labels, nebula positions, atmosphere, ground, constellation lines, art and labels on and off further enriches the experience and all are done via the said menu.
The aforementioned *.pdf userguide shows the breadth of options and possibilities of Stellarium. From everything like scripting, creating landscapes, adding Nebula images, taking screenshots (using Ctrl and s keys) and to the many command line parameters.
Stellarium is open source cross platform software and requires a graphics card capable of rendering OpenGL. An *.ini configuration file written into the program folder is accessible from the program’s start menu and offers another way to tweak the characteristics of Stellarium, for example the presentation font can be changed here but there is much more and some are detailed on the FAQ page.