The function I wanted most out of my Palm was a handheld way of determining the current orientation of Mars, and what features should be visible. No one else seems to have written such an app, so I decided I had to try writing it myself. In the process, I had to learn how to develop for PalmOS under Linux.
Doing floating-point arithmatic on the Palm is hard, so at first I wrote a program using all-integer math, using the algorithm from the 2001 RASC Observer's Handbook (which probably won't be accurate for future oppositions). It's fast and fairly accurate, but ugly (Mars isn't round, for one thing). You can advance or retard the time by dragging. Drag right or left to rotate the planet ahead or behind by an hour; tap with the pen to reset to the current time. (It's out of date now, but if you want you can download Mars2001 (12.5K .PRC).
Then Brian Tung, author of PleiadAtlas, and I collaborated on a better version, MarsMap, with much better graphics and UI.
Download MarsMap 0.7.2 (28.6k .PRC)
MarsMap requires MathLib to do the floating-point math. If you don't have MathLib already, you'll probably need it for other astronomy programs soon.
The links point 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 or (mac) click-and-hold 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).
A note about Coordinates: "E" and "W" in MarsMap refer to Mars-centric coordinates, using post-1960's IAU coordinates (east is right when north is up, just as on Earth). Some Mars programs label east and west differently, but this seems to be because they're labelling the coordinates of the celestial sphere, not of the planet Mars. This is confusing, and people tend to get even more confused because of getting crossed up by using star diagonals. When communicating with fellow Mars observers, I recommend using terms like "preceding" and "following" (refering to Mars' rotation direction) rather than "east" and "west" to reduce confusion. (North and south are unambiguous and can be used without problems.)
If you have any problems with this version, do let me know -- but you may also want to try Brian's version, since his version and mine have diverged a bit. His is slower to draw but has some nice new features. We're working on getting our two versions back in sync.
Both programs use 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 PST, GMT-8 (because that's where I live).
Other Palm Programs: Try my Palm programs SatMoons and Jup: SatMoons shows the moons of Saturn, and Jup shows Jupiter's moons, moon shadows, and the red spot.