Portable Sky

Portable Sky is a full-featured planetarium that fits in a pocket. Designed for PDAs and other devices that use the Palm OS operating system, Portable Sky allows you to track the positions of the sun and moon, stars, planets, galaxies and other deep-sky objects--even comets and earth-orbiting satellites. You simply enter your local latitude and longitude, and Portable Sky will show you what objects are visible in your sky, their precise locations, how bright they are, their rise and set times, and a wealth of other information.

You can examine a chart of the entire sky, or you can target a specific part of the sky and zoom in for a better view. You can select which objects to display. You can choose to display right ascension and declination lines (the astronomical equivalent of longitude and latitude), altitude and azimuth lines, and the ecliptic (the path along which the sun, moon, and planets appear to move through the sky). You can choose a dark-on-light or a light-on-dark mode for night viewing.

Are you interested in the relative positions of the planets in their orbits about the sun, and the moon in its orbit about the earth? Portable Sky will show you that with the click of a button. Want to know the phase, brightness, orbital period and distance of Mars? Another click will show you that.