[amsat-bb] Re:Re: Sun Kepelerians..

["Stacey E. Mills" <w4sm@xxxxxxxxxx>]

Vince Fiscus said:

>Are you the ghost of Claudius Ptolemy? HI
>I've studied this and the mechanics of orbiting bodies.  I'm not an expert,
>but I don't believe you can come up with an element set that will track the
>sun using the algorithms found in our typical amateur radio satellite
>tracking programs.

Vince, I'm sorry but you are wrong about this.  The keps that I posted, or 
similar ones, will track the sun quite well.  Even though these are "keps" 
from 1995, they agree within a fraction of a degree with my more precise 
TrackSM software.  After all, the decay in this system is 
negligible!!  This has been covered on this bulletin board many times in 
past years.  Obviously, these are "pseudokeps".  The sun doesn't  REALLY go 
around the earth, but the model works fine from our perspective here on the 
earth's surface, if you assume it does (once a year!).  Only the distance 
calculations are off because the mass of our "satellite", ie. the sun, is 
most definitely not a negligible component of the system's total mass, as 
is assumed with a man-made satellite.

As has also been covered here before, keps for the moon are much more 
difficult because the moon's orbit perturbates quite a bit.  There are 
complex algorithms typically used to track the moon's orbit.  However, keps 
can be generated that are reasonably good for a few weeks.



-- 
  _______________________________________________________________________
  Stacey E. Mills, W4SM    WWW:    http://www.cstone.net/~w4sm/ham1.html
   Charlottesville, VA     PGP key: http://www.cstone.net/~w4sm/key
  _______________________________________________________________________

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