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From: gsh7w@astsun.astro.Virginia.EDU (Greg Hennessy)
Newsgroups: sci.astro,sci.space,sci.space.shuttle
Subject: ASTRO status at 3/20:54
Message-ID: <1990Dec6.034418.11729@murdoch.acc.Virginia.EDU>
Date: 6 Dec 90 03:44:18 GMT
Sender: news@murdoch.acc.Virginia.EDU
Organization: University of Virginia
Lines: 42


The observational efficiency of the ASTO observatory continues to
increase, but not as quickly as hoped. The star trackers work
perfectly whenever tested, but still have not worked on a real object.
All science done so far ahas been by the astronauts hand guiding the
telescopes, which results in much less stable images than the nominal
star trackers. The star trackers can be made to work in a certain
fashion, a complicated procedure, but this procedure takes so much
time that it often eats up most of the observing time. The last tests
on teh star tracker show that the three tubes that compose the star
trackers are misaligned by 0.9 degrees. They are supposed to be
coplanar. 

During the eigth shift, two problems occured that lost observing time.
One was the crew exercising on the treadmill diring an observation
of P Car. The premission understanding was that the crew would only
excercise during handovers (times when so science was being done) but
this was apparently not written down anywhere. The crew will now only
excercise when the shuttle is in an SAA, a region of higher radiation
where the instruments do not work. Also during the mission the
verniers (small rockets which keep the shuttle pointed in the proper
position). Since this meant that the shuttle had to manuver using the
large rockets, the shuttle doors were closed to prevent contamination
from the fuel, which contains hydrazine. Three observations were
missed, unfortunately the high priority targets the Pleiades,
VW-Hydra, and the cluster Abell 2199. (Talk about rotten luck). These
four targets had zero science done, and specified observation times of
16, 23, 40, and 34 minutes. Sucessful observations were made of the
galaxy 0558-504 with 10 of 15 minutes (67%), M79 (14 of 27, 52%),
SK69-239 (18 of 33, 55%), M79 again (31 of 45, 69%), NGC 1399 (10 of
26, 38%), P-Cyg (33 of 38, 65%), 3C273 (everybody's favority quasar)
41 of 47, 87%, Capella, 12 of 28, 43%, and HD99264, 20 of 29 minutes
for 70 percent. All in total, 39 percent of the scheduled time was
done, compared with 36% for shift 7, 17% for shift 6, and 0% before
that. The next shifts observations will be done with a software patch
to correct for the misalighed star tracker.

--
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      gsh7w@virginia.edu  
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