Did you know that Predict and Xplanet can be run together sharing the same 2-line elements.?

On my Mac, Xplanet looks in $HOME/Library/Xplanet/ for local configuration data, so I created a satellites directory under that and the set up a text file called satellite with the following contents:

25544 "ISS" color=0xa0a0a0
25544 "" trail={orbit,-10,0,1} color=0x200020
25544 "" altcirc=0  color=0x101010
25544 "" altcirc=10 color=0x044004
25544 "" altcirc=40 color=0x400202
25544 "" trail={orbit,300,0,1} color=0xa000a0

28375 "AO-51" color=0xa0a0a0
28375 "" trail={orbit,-10,0,1} color=0x202000
28375 "" altcirc=0  color=0x101010
28375 "" altcirc=10 color=0x044004
28375 "" altcirc=40 color=0x400202
28375 "" trail={orbit,300,0,1} color=0xa0a000 

and made a symbolic link from $HOME/.predict/predict.tle to $HOME/Library/Xplanet/satellites/satellite.tle

Runing Xplanet with the following commandline options:

xplanet -geometry 750x750
   -projection orth
   -latitude 53.6
   -longitude -2.5
   -wait 10
   -gmtlabel
   -color 0xffffff

(all on one line...) gives the following results.

AO-51	ISS

The control file is set up to show the next 3 orbits and the previous 10% of an orbit, along with altitude circles for 0 degrees; 10 degrees and 40 degrees in different colours.

The examples here are shown for a Mac, but will run in a similar fashion on a Linux system. Note that Predict isn't requred to produce the Xplanet output - they are only sharing the same 2-line elements data file.

On the Mac Xplanet will run without X11, and extending this idea further allows you to drop the Xplanet graphic as a wallpaper image either on its own or superimposed over an existing wallpaper image.

In both images they show ISS passing to the East over Africa and AO-51 (Echo) coming over the North Pole along with partial passes of various other satellites. I set the previous trail on ISS and AO-51 to show the last 10% of a pass along with the next 3 orbits calculated by Xplanet. The remaining odds'n'sods are set to show just the next 30% of each orbit so that the image doesn't get too cluttered.

If you use the default settings for 'projection' the satellite orbit trails are shown at their respective altitudes, whereas the 'orth' projection shown in the first two images show the orbits on the surface of the planet.

I used Platypus to package up the startup script so that it can be started at logon.

I really like the one on the right where the background image shows Sarah Michelle Gellar apparently looking to her left at the globe. But then again SMG looks good in any image.. :-)