21 March 1994
							  L. Acton

               SXT CHIEF OBSERVER REPORT AND TABLE PLAN
 FOR 14 March - 19 March 1994

TABLE PLAN:   (21 March - 26 March 1994)
	No special SXT operations observing are planned for this week. 
Monday at Pass 2 the frequency of long exposures will be increased
because the sun is so quiet.  The weekly DKCAL will be done on Wednesday
at PASS 4 and the standard table at PASS 2 on Thursday. 
	
 JST day	    Table ID		       KSC contact start time

 Monday		940321 P4 ARS2 STD+LONG 	21-Mar-94 22:44 JST

 Wednesday 	940323 P4 ARS1 DKCAL		24-Mar-94 01:08 JST

 Thursday  	940324 P2 ARS1 STD+LONG		24-Mar-94 22:02 JST

NOTE: 
	This is a preliminary listing and changes in table ID and upload
schedule may happen.  Some uploads may be changed or canceled.  The fax
message prior to the table upload should be definitive.  Thank you. 


                                                  3/21/94  Page 2

                SXT CHIEF OBSERVERS REPORT  21-Mar-94

U-SIDE PERSONNEL
	Slater will arrive 21-Mar-94.

CAMPAIGNS/VISITORS
	Karen Harvey has reviewed the SXT data from the XBP campaign and
reports interesting events and variability.  She and Jack will visit
ISAS, bringing the magnetic field data from NSO/KP starting 23 March.
	Len Culhane will arrive at the same time for a short visit.

FALSE FLARE FLAGS
 	No false flare flags this week.

COMPUTERS/NETWORK
	Thank you for updating the mail handling utility in MADRID.
	The connectivity to INTERNET went down early Sunday and remains
down on this J-holiday.  The timing is unfortunate!

PROPOSED CHANGE IN STANDARD OPERATIONS
	This past week we experimented successfully with changing to
medium telemetry bit rate during the SAA.  (See report below.)  This
improves the quality of SXT data and I recommend that OP_FIRST_GUESS be
changed to make this routine normal operations.

                                                  3/21/94  Page 3

From:    L. Acton 
Date:	 Mon Mar 21, 1994
Subject: SXT and SAA, data evaluation.

CASE 1:   Change to/from medium rate with HV off/on.

	HV off (QT/Med)			14-Mar-94 15:33
	SAA start from model		14-Mar-94 15:40
	SAA effects PFI			14-Mar-94 15:42

	End SAA effect on PFI		14-Mar-94 16:03
	SAA end from model		14-Mar-94 16:11
	HV on (QT/Hi)			14-Mar-94 16:12

In this case, for SXT, the change to/from medium rate is too
conservative by about 9 minutes on each end.  Also, the BDR is not
filled in one daylight orbit so observing time is wasted.

CASE 2:  Change to/from medium rate 7 minutes after/before HV off/on.

	SAA start from model		19-MAR-94  13:54:40
	Change to Medium rate		19-MAR-94  13:55:40
	SAA effects PFI			19-MAR-94  13:58

	End SAA effect on PFI		19-MAR-94  14:11
	Change to High rate		19-MAR-94  14:18
	SAA end from model		19-MAR-94  14:25:20

In this case there is still about a 2-5 minute margin between high rate
and SAA effects and the BDR is overwritten by about 10% -- but very
little good data is replaced by SAA data because, at medium rate, only a
small amount of data is taken during the SAA. 

Case 2 is satisfactory, it is OK to key the the rate change to HV
off/on.  All SXT needs is an adjustable time offset parameter.