ClearSky Free is a planetarium designed to be easy to use and very customizable providing a pleasant view of the sky. Instead of being focused only in brilliant 3d graphics ClearSky is focused on providing a pleasant user interface and a superior accuracy capable of simulating accurately almost any astronomical event from solar/lunar eclipses to even mutual eclipses and occultations between the satellites of Jupiter Saturn and Uranus. In addition ClearSky provides a very complete list of astronomical events even in its free version bringing true astronomy close to you. Although it is very easy to use it a help document describes it in detail and lists the many benefits of the optional complete version of the program. ClearSky is free of adds English and Spanish languages are completely supported and uses Internet access only to download updated data never to uppload. Main characteristics of the free version are:

- The sky simulation is static in time and updated in intervals of few minutes (customizable). The objects will not move around all the time and it will be easier to zoom or explore around them.
- Clear representation of the sky in realistic or chart-like styles with several color profiles in the sky and the user interface for different situations. By default the automatic mode will use red colors during the night. Text size in labels is customizable.
- Easy to use interface with double click to center zoom gesture for fast zoom in/out operations and long click for a context menu to access the details of the body. A little menu at the bottom provides the basic functionalities with an optional full featured menu that shows the Earth with artificial satellites a bar with the visibility of the planets and many useful options. Rotation gesture is by default disabled since the sky is shown in a straight way.
- Direct access to the visibility of the planets in a bar located in the main menu. The bar is clickable to access additional information.
- News and APOD (astronomy picture of the day) integrated.
- Comets asteroids extrasolar planets space probes radiants of meteor showers different constellation lines image inversion to emulate telescopic
view different coordinate and projection systems... These and many other configurable options are well distributed in categories with two levels. By default only the main options are shown the advanced mode can be enabled in the interface section.
- Realistic planetary renderings of all Solar System bodies with an accurate representation of lunar eclipses the aperture of the rings of Saturn the position of the Great Red Spot in Jupiter the features of Mars or any other body currently visible from Earth and the position of the natural satellites. 700 deep sky textures are also accurately rendered within the stars.
- List of the next main astronomical events (eclipses lunar phases meteor showers transits of ISS and other satellites and many more) with options like simulating them or setting an alarm.
- Automatic update of orbital elements for comets and asteroids will keep accurate positions and will show new possible comets getting close to the inner Solar System.
- Trivia game with 55 questions.

Although ClearSky Free will be enough for a basic user (and not so basic) the complete version focused on amateur astronomers with telescopes uncovers the full potential of ClearSky. Have a look to the ClearSky page or at end of the help document for a complete list of the additional features.