These programs show useful details about planets, intended for use while observing or for predicting events which might be observed. They run on PalmOS and Unix (under X).
SatMoons shows Saturn's moons and the tilt of its rings. Version 0.8 has been updated to be more accurate for the 2002-3 opposition.
Download SatMoons v. 0.8.2 (23.7K .prc)
Jup shows the position of Jupiter's four Galilean satellites, their transits and shadow transits, and the position of the Great Red Spot. If you downloaded version 0.2 or earlier, there are errors in the positional display. I recommend picking up version 0.5, which corrects an east/west reversal and updates the location of the GRS to 75 degrees (system II) for 2002.
0.8.2 has the labelling improved -- situations where the labels weren't visible, especially on shadows, should be better now. (Labels will still sometimes overwrite each other, though.)
Download Jup v. 0.8.2 (23.9K .prc)
Each link points directly to the prc, not a zip file. Depending on your browser, you may have to use shift-click to save it, or right-click (click-and-hold on the mac) on the link to get a context menu, then chose "save as". If you're on Windows and your browser maps carriage returns on download, I don't know how to fix that (maybe a Windows person can tell me).
It uses Location Manager to get your time zone. You need Location Manager version 1.50 or better, If you have an earlier version, things might not work right. If you don't have Location Manager, it will default to a time zone of PDT, GMT-7 (because that's where I live).
It also depends on having MathLib, like most astro programs which use floating point calculations.
Other Palm Programs:
Mars programs, MarsMap and Mars2001.
I also have a very minimal attempt at a moon ephemeris program called lunatic which shows terminator position and current optical libration, like my Hitchhiker's Guide to the Moon. I also have PDA versions of the Hitchhiker's Guide itself available in two Palm formats: Hitchhiker for iSilo (116k) and Hitchhiker for Plucker (137k) The Plucker version is slightly larger, but Plucker has the advantage that it's free, whereas iSilo isn't ...
(Note: I also have some Java astronomy apps including Zaurus packages.)