M42 "sat photo"

Matson, Robert (ROBERT.D.MATSON@saic.com)
Wed, 22 Sep 1999 15:49:00 -0700

Hi All,

Well, now that Jim has posted the M42 photo, we can put the
satellite track question to rest.  It's a diffraction pattern.
The north-south tracks are perfectly north-south; if there
were only one, then it would be possible -- though very rare.
The satellite has to be at just the right combination of
altitude and inclination to appear to move exactly N-S.  But
with *two* right next to each other, without any others at skew
angles?  Virtually impossible.  Indeed, there are satellites
that DID go through the field of view during the exposure that
nevertheless aren't there.  (Since the satellite image is in
constant motion, it doesn't spend enough time on a given pixel
to register enough energy.  I doubt that even 6th magnitude
satellites would be visible.)  Still, it's been a fun sleuthing
exercise!  --Rob