1 XPHOON
    
     xphoon - displays the PHase of the mOON on the root  window  

     xphoon [-b] [-t interval [-i]] [-s] [-display name]

  Xphoon sets the  X root window to a picture of the moon in its current
  phase, including the partial lighting of  the  dark  side  by 
  reflected earthlight.   

2 Options

-b

  Defeats  the  earthlight  feature, forcing the dark side to be black.

-t

  Have xphoon keep running and update the picture every minutes. 
  (Normally, just xphoon sets the root picture and exits.) 

-i 

  Forks a background process and prints the process-id to stdout. 
  Useful if you want to make menu commands to refresh or kill xphoon.

-s

  Rotate the whole picture 180 degrees, resulting in a moon picture as
  viewed fom the Southern hemisphere.

-demo

  Demonstrate xphoon by rapidly stepping through moon phases.

2 Notes

  The original motivation for this program  was  that  xsetroot  was
  too slow. Loading  a full-screen  bitmap  took  about  15  seconds. 
  We made a trivial program that had fullmoon.bitmap compiled in, and
  it ran in  less than  a  second.   (And  incidentally, the executable
  was smaller than fullmoon.xbm.) Then later we came up with the phase
  hacking, the  earthlight,  and the auto-scaling.  

2 See_also

  phoon, xsetroot
  
2 Authors

  Copyright (C) 1988, 1991 by Jef Poskanzer and Craig Leres.

  The moon-phase computation is from "moontool.c" by John Walker.