Stars and Planets app for iPhone and iPad

This application allows to compute and show the position in sky (Azimuth and Height) of the major stars and planets.

First, you have to define the observation point, selecting it from a list of the main world cities, or capturing the current position detected by the internal GPS.

Second, you have to select date and time of observation, indicating it as the GMT time (Greenwich Meridian Time). You can obtain it by subtracting from your local time, your time zone, and the eventual summer daylight saving time for your country. The application helps you, computing an estimate of it, based on the longitude of the observation point. But in any case you have to check and confirm it.

Finally, you can select the star or the planet you want to observe. The application computes and shows its celestial coordinates at the selected time, as seen from the selected location.

The position of a celestial body is defined by two angles: Azimuth (starting from 0 at north, and growing to 360 in horary sense), and Height (starting from 0 at horizon, and growing to 90 at Zenith).

For stars and planets, the Magnitudo (index of brightness) is also shown, while for the Moon the phase (0 to 100%) is shown instead.