Laser Beams From Space

The laser altimeter aboard ICESat was powered on again Sept 26th and is
planned to remain on for 45 days.  When atmospheric conditions and
observer positioning are right, green light from the laser can be easily
seen from the ground.  Thin clouds, numerous scattered clouds, or haze
should all provide good conditions to observe the laser beam.  Clear is
not good unless the observer is within a few hundred meters of the
laser’s ground path.  To observe the laser in even good conditions it is
thought best to get close to the satellite’s ground track as the forward
scattering from the Nadir pointing laser may not be visible more than a
mile or less off track.  The apparition's speed is remarkable as the
laser spot is moving at orbital velocity.  

(For more info refer to the “Observing ICESat” thread on this newsgroup
in March of this year)

Gregg Hendry