SXT Status Report
                     December 10, 2001 - December 23, 2001
                                (Weeks 50-51)
         
                        H. Hudson, J. Sato, A. Takeda 


SOLAR ACTIVITY

This is not a routine report, because Yohkoh ceased returning scientific
data on December 14. This "furlough" is somewhat analogous to SOHO's.
We discuss this below and also in the science nugget for December 21. 
The solar activity during this two-week period was high, with two more
X-class flares.

OBSERVING CAMPAIGNS

Yohkoh participated in no coordinated observations during these two weeks.

Please see our webpages for details about campaigns past and future:
http://isass1.solar.isas.ac.jp/sxt_co/sxt_catalog.html
http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html

SXT INSTRUMENT STATUS AND CALIBRATION ACTIVITIES

Data ended December 14 as a direct result of the near-total solar eclipse
of that day, which Yohkoh intercepted over the Pacific Ocean midway between
Hawaii and the Galapagos. This resulted in a loss of control and an 
under-voltage condition. Please see the science nugget for December 21 for 
fuller details. The situation is analogous to that of SOHO during its 
temporary loss in 1998; we know where Yohkoh is and know that it is alive. 
Unfortunately it is rotating at about 1 RPM around its Y axis (solar EW 
direction of motion) and slowly precessing. The problem will be to coax it 
back into normal operations. The Yohkoh team is working hard on this.

TELEMETRY DOWNLINKS

Week  Wallops Santiago Goldstone Canberra Madrid NASA  Japan
50       30        4         0        2      2   38    27
51        0        0         0        0      0    0    31

Kagoshima should average 6*5+2 = 32 and the NASA target is 7*6 = 42. 

SXT OBSERVING SEQUENCE TABLES

====================================================================== 
JST Day         UT Start Time      Pass        Table ID

Monday PM       10-DEC-01 10:33      2    011210 P2 ARS1 STD
Tuesday PM      11-DEC-01 12:08      4    011211 P4 ARS1 DARK
Wednesday PM    12-DEC-01 07:00      1    011212 P1 ARS1 DIFF
Thursday AM     12-DEC-01 10:21      3    011212 P3 ARS1 STD
Thursday PM     13-DEC-01 08:34      2    011213 P2 ARS1 STD
Friday PM       14-DEC-01 08:28      2    011214 P2 ARS1 ECLIPSE

====================================================================

Data reformatting is complete through December 1, 2001 (week 48).

OBSERVING SEQUENCES:

The PFI tables had 2x2x2 observing regions in QT/Hi and 1x1 ORs in QT/Med and 
FLARE modes.

SCIENCE NUGGETS:

December 14: "The annular eclipse of December 14, 2001," reports on
the annular eclipse of December 14.

December 21: "Yohkoh's troubles," gives a fuller account of the loss of
control and current status of the spacecraft.

The full list of recent nuggets is kept on
  http://isass1.solar.isas.ac.jp/sxt_co/index.html 

and the current week's nugget also normally resides on
  http://isass1.solar.isas.ac.jp/sxt_co/SXTweekly.html

For the complete nugget archive, see one of the following sites.
  http://isass1.solar.isas.ac.jp/nuggets/     (Japan),
  http://solar.physics.montana.edu/nuggets/   (Montana),
  http://www.lmsal.com/YPOP/Nuggets/          (California) and
  http://ydac.mssl.ucl.ac.uk/nuggets/         (UK).

Note that we plan to maintain the nugget-writing through the Yohkoh furlough
period based upon existing material.

SEMINARS:

There were no seminars during this period.

PERSONNEL:

J. Bartus departed on Dec. 14 for holidays.
H. Hudson returned to ISAS Dec. 18; 

TOHBANS (spacecraft operators) for week 50

SSOC Tohbans : T. Morimoto  I. Suzuki
KSC  Tohbans : K. Shinoda   T. kichiraku
SXT_CO: D. McKenzie, J. Sato
SXT_SW: J. Bartus

TOHBANS (spacecraft operators) for week 51 

SSOC Tohbans: R. Kano & I. Sano
KSC  Tohbans: T. Kichiraku & Y. Katsukawa 
SXT_CO: H. Hudson 
SXT_SW: -