low altitude: STS-86

Walter Nissen (dk058@cleveland.Freenet.Edu)
Tue, 30 Sep 1997 12:20:26 -0400 (EDT)

Saturday morning, Atlantis was still about 2.5 minutes behind Mir when I 
was able to follow her flight to what seemed to me to be a very low 
altitude.  (I didn't follow Mir similarly because neither my binoculars 
nor my brain are equipped with split-screen mode; but I might mention that 
I did plan the pickup (AOS for you radio types) for Mir very carefully and 
was able to see her emerge gradually and in various garbs of red and 
orange, much like what Ron Dantowitz has described from computer 
tracking).  I finally lost sight of Atlantis at 19970927 092904.48 UTC. 
As one of the leading advocates of recording, measuring and reporting 
astrometric positions, I should mention that there were no visible stars 
anywhere in the vicinity to make an astrometric position possible. 
I'm not sure how accurate this elset from JSC (I didn't find anything 
which looked better at OIG) is: 
STS-86 Atlantis-Predicted Post NC3 
1 24964U 97055A   97270.17990931  .00002738  00000-0  36798-4 0  9071 
2 24964  51.6515 293.3433 0038250  54.8519 305.6217 15.69858480   184 
but using it and a small personal equation (the difference between eye and 
the hand on the stopwatch, perhaps a poor .7s for this OBS), I compute an 
altitude of 
                                2.2 degrees 
for Atlantis at that time.  I doubt I've seen any LEO much lower.  I don't 
know how this compares to extreme low altitude OBS of other observers. 
Walter Nissen                   dk058@cleveland.freenet.edu 
-81.8637, 41.3735, 256m elevation 
Venusset is much underappreciated.  Watch 50 or 100 of them to an altitude 
below 1 degree and you'll never trust the atmosphere or a UFO report again.
This entertainment is readily available in the evening this season.