This is beta software. When it's ready for release, there will be downloadable, standalone applications for both Mac OS X and Windows available here.

Times shown are the Local Time (LT) and Universal Time (UT). Also shown is the rotation of the Central Meridian System II (CMII); the meridian that keeps pace with the GRS. Julian Date (JD) is also displayed. The "Next Transit" indicator is a countdown clock telling you how long it will be before the next transit occurs in hours and minutes. Night vision mode will be more useful when this is a standalone application. Of course, it's not useful while embedded in a white Web page.

How did I build this?
I created a 3D spheroid in Maya, adjusted the vertical scale for Jupiter’s oblateness (bulge around the middle), and mapped a 2D JPEG to the spheroid. I then added lighting and rendered out a 360° movie of Jupiter rotating. Next, I imported the movie into Flash and used some math I found on the Web to calculate Jupiter’s rotation in degrees. Once that was known, I could display the correct image to match the rotation...for example, if Jupiter is rotated 45° I simply display frame 45 of the movie.

Thanks to Björn Jónsson for his excellent map of Jupiter crafted from Voyager photos. Thanks to Bill Gray of Project Pluto for helping me with the math.