To:sot_shift
from: Dan Schwartz
date: 26 Aug 99, 10:00pm EDT
Subject: SOT shift report, Shift M36
--------
See http://asc.harvard.edu/acis/SOT_reports/sot-shift.html, or 
/proj/ascwww/AXAF/extra/science/htdocs/acis/SOT_reports/Aug_26_1999_M36.txt.

Shift M36
	Start at 238:18:00  GMT
		 = 02:00pm 26 Aug EDT
	End	   10:00pm 26 Aug
   
SOT Lead	DAS
Spac/Aspect	RAC,MF
FOT/Sci liason	ERM
HRC		
ACIS 		LT,RB

(Times will be given in GMT on day 238/239. In general
times are rough, not precise.)

PLAN
Run under stored command segment P8.
Finish OBSID 0065 observing NGC 2516.
Shut down ACIS to enter radiation belts.

EVENTS
Start of shift, OBSID 0065, 5 stars, 3 fid lights.
18:44  ACIS stop science run
20:13  ACIS video boards power down.
20:40  EPHIN rates start to increase. Actual belt entry.
21:40  Start CAP 338, to playback contents of ACA memory, to aid
	debug of failure to acquire stars. 
00:00  LOS.

NOTES/ISSUES/PROBLEMS
Because the OR for OBSID 0065 only requested 11,000 sec on NGC2516,
and because there was nothing else for the scheduler to do, we 
SAT IDLE, WITH ACIS TURNED OFF, for 5500 seconds while pointing
at NGC2516 !!   4800 seconds of idle time are planned while 
pointing at the CRAB Pulsar at 238:18:40:35, for OBSID 0168. 
CAN THESE BE AVOIDED IN THE FUTURE??  FOT/MP is working on it!

CSC has developed a fix to the OFLS system, to correct the positions
searched for fid lights when the SIM is translated. This will be 
brought up here for testing tonight or tomorrow, and is planned
to be installed prior to generating the P9 loads. 
It is REQUIRED for P9 loads.

P8b has been replanned to restore most of the time needed for OBSID
1237, the HETG focus on Capella.  This uses the CRAB pulsar idle
time mentioned above to good advantage.
The reworked schedule and command loads for the second half of Part 8
are now complete and products are available.  This schedule takes 
up at 240:07:50, and continues through 242:06:20. The review meeting 
for these products is currently scheduled for Friday,
Aug 27th, at noon.  ACIS, RB, has reviewed and approved the DOT
md240:0718.dot (if it doesn't change).

The CAP 338 investigation was extremely fruitful.  A 10.2 magnitude
star failed to be acquired via OBC commands. However, in monitor 
mode it showed 2100 counts -- at strong signal that should be
easily tracked.  When the ACA was commanded directly from the 
ground, the star was acquired and tracked! This indicates that
faint star acquisition failure is an OBC software and/or K-constant
problem.
T. Aldcroft finds that the OBC code does indeed impose a threshold,
and identifies the relevant K-constant!!

-------------------------------------------------------
Dan Schwartz,	MS #3
das@head-cfa.harvard.edu  
phone: (617)495-7232    FAX:   (617)495-7356
cell phone: (617)512-5627   
pager: 800-759-8352 PIN 1636502
       or e-mail 1636502@skytel.com 
-------------------------------------------------------