Some of my most-used Astronomy software actually runs on PalmOS ® handhelds rather than the PC. Following are links to the programs that I use most often, along with a brief description of each:
Planetarium
Okay, so it's not free like the PC-based programs. However, it's one of the best investments I have
made in this hobby. Planetarium is the best sky-mapping tool I've seen for handhelds, with a number of other utilities built in as well. In addition to displaying sky maps for any given time and date, you can search for a given object in the sky map, add finderscope (or Telrad) circles on the viewscreen, and check planetary statistics such as the positions of Jupiter's moons or the phase of Venus. Planetarium is even capable of directly controlling most GOTO scopes. Check out the web site for more details!
Jovian
Jovian is another shareware program that I use fairly often. It shows the relative positions of Jupiter's moons, and the location of the Great Red Spot. Excellent graphics, an intuitive interface, and its low price make it a great deal.
Jup & SatMoons
Jup & SatMoons are both high-quality freeware. While they do not have a sophisticated user interface like the previous two programs, both provide unique functionality that I have not found in any other Palm-based programs. Jup not only identifies Jupiter's four largest moons and GRS, but also displays the moons' shadows, which is great for predicting (or confirming) transits. SatMoons is a similar program which gives the relative location of Saturn's moons and the inclination of its rings for any give date and time.
Note: The GRS longitude in Jup is now out of date, so it should only be used for predicting positions of the moons and shadows.
For more programs and in-depth information, check out the Palm_Astro discussion group at http://groups.yahoo.com
.