Re: glints

Bill Welker (wwelker@spieg.interealm.com)
Wed, 10 Apr 1996 07:22:04 -0600 (MDT)

On Tue, 9 Apr 1996, Jim Varney wrote:

> I would say based on the above that UARS is the biggest glinter of them
> all.  HST might top it, but most of us in the temperate latitudes miss out
> on what it can really do.  DMSP with its negative magnitudes belongs in the
> top glinter league.  I'm willing to concede that while Tiros N does
> glint, it doesn't rate as 'notorious.'
> 

True, I watched the HST one morning from just south of the cape in FL and 
caught a spectacular glint - briliant gold, I estimated mag -7, 
definitely from the solar panels.  From Denver, I've never seen the 
entire beast brighter than +4.

> 
> Our theory -- that solar panels not tracking the sun cause bright glints --
> is not the only mechanism that causes glints.  All of the other satellites
> you cite show, as you say, that something other than the solar panel is
> responsible for the glint.
> 

The phrase "not tracking the sun" causes me the same grief that 
"tumbling" is causing some folks now.  The HST and, I assume, most other 
satellites with fixed solar panels must do orientation manouvers to 
re-point the solar panels at the sun.  In the case of the HST it is 
intentionally repointed to an astronomical object and the panels must 
necessarily be redirected to the sun.  Certainly the opportunity exists 
to catch a glint from a solar panel during vehicle reorientation!  A 3 
axis stabilized vehicle keeping some instrument pointed at the earth is 
often going to need a major rotation about one or more axes to redirect 
the solar panels to the sun.

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** Bill Welker ** wwelker@nexus.interealm.com ** My Opinions Only     **
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