Juplet/Satlet/Moonlet: Astronomy Java Applets

These were originally written as browser applets in Java, and then ported to the Zaurus PDA. I haven't tried them on more modern phone/tablet platforms like Android (because I don't have the hardware), but I'd love to hear from anyone who ports them.

[Satlet screen shot] Satlet shows the position of Saturn's moons. It also lets you drag in the field to change the time by small increments, click on +/- buttons to zoom in and out, and has a time-setting dialog (which I will eventually migrate to the other two applets).
[Juplet screen shot] Juplet Shows the Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto), moon shadows, and the Great Spot Formerly Known as Red. It's fairly mature (I've been using the online version of this applet regularly since I wrote it in 1996) and probably won't change much, except maybe to add a better UI for changing the date.
[Moonlet screen shot] Moonlet shows the phase of the moon.
I fixed the flickering while drawing problem! Zaurus users will particularly appreciate that; pick up the 0.4.2 ipkg.
To Do: I'd like to be able to read values out of that pixmap so that I can show earthshine. I also want to give libration information (I have code in other apps to do this, shouldn't be hard to add) and rise/set times (due to the moon's equations of motion, this involves typing in a long table of numbers, which is really boring, so I've been putting it off). And I need to integrate the date dialog from Satlet.

Here's where to download the Zaurus IPK installer, (243k, includes all three applets), and here's the source (akklets-0.4.2.tar.gz). To see the applets run in your browser, click on the link for a specific applet, below.

You can also find these applets on Ultrastudio.org, which has a great collection of other educational applets as well.

Source Change Log

Most of the code was written in 1996 and hasn't changed appreciably since then. Hidden in the tarball is also a mini-starchart app which I wrote to keep track of comet Hale-Bopp, since nobody else on the web had finder charts then. The star chart doesn't currently work because I deleted the star list back when I was short of disk space; eventually I'll get around to generating a new star list and updated comet elements, and then the star chart will be usable again.

9/9/2003: 0.4.2 Fix moonlet flickering while drawing.
1/18/2003: 0.4.1 Minor cleanup.
10/21/2002: 0.4 Introducing Satlet, with code to change time by dragging in the canvas, and a little time-setting dialog.
9/23/2002: 0.3 Fix image size, clean up images, turn on earthshine mode, other minor tweaks.
8/30/2002: 0.2 Use an image instead of an all-white moon.
8/21/2002: 0.1 First Zaurus release.

Zaurus owners and Linux users might also be interested in my Just Moon program.

I also have some PalmOS astronomy software.

Akkana's Software
Shallowsky Home
mail me

	Satlet shows the position of Saturn's moons. It also lets you drag in the field to change the time by small increments, click on +/- buttons to zoom in and out, and has a time-setting dialog (which I will eventually migrate to the other two applets).
	Juplet Shows the Galilean moons of Jupiter (Io, Europa, Ganymede and Callisto), moon shadows, and the Great Spot Formerly Known as Red. It's fairly mature (I've been using the online version of this applet regularly since I wrote it in 1996) and probably won't change much, except maybe to add a better UI for changing the date.
	Moonlet shows the phase of the moon. I fixed the flickering while drawing problem! Zaurus users will particularly appreciate that; pick up the 0.4.2 ipkg. To Do: I'd like to be able to read values out of that pixmap so that I can show earthshine. I also want to give libration information (I have code in other apps to do this, shouldn't be hard to add) and rise/set times (due to the moon's equations of motion, this involves typing in a long table of numbers, which is really boring, so I've been putting it off). And I need to integrate the date dialog from Satlet.