Celestial Guide is an interactive database of information about stars and planets. Its basic interface is a map of the sky as seen from any point on Earth at any point in time.

The user can manually choose the time and location, or the iPhone's or iPad's GPS and clock can be used to select the current time and location. If the device is pointed at the sky, the map on the screen will be presented corresponding to the actual view in that direction.

The star database includes stars brighter than magnitude 9. The user can select the minimum visible magnitude, which allows the map to conform to the stars which are visible to the user based on local viewing conditions.

CelestialGuide presents accurate locations of planets and comets, including rendering of eclipses, transits and occultations that are visible from the selected location. CelestialGuide also has a database of Messier Objects.

CelestialGuide also includes a Virtual Orrery, displaying the relative position of the planets and comets at any point in time.