SXT REPORT FOR WEEKS 48-49

                         29 Nov 1993 - 13 Dec 1993               
                                                              13 December 1993
                                                                   James Lemen


GENERAL STATUS
     
     The SXT and the Yohkoh spacecraft are working well.  The solar activity
has been pretty low.  A bright point campaign was conducted 29 Nov - 3 Dec.



PERSONNEL

     Currently, the ISAS SXT personnel consists of J. Lemen.  H. Hudson, N.
Nitta (who recently returned from the the Hawaii workshop) and S. Freeland
(who returned from a brief trip to Calif). Franta Farnik (Ondrejov, Praque)
is still visiting for another couple of weeks.  J. Lemen will return to 
Palo Alto on 14 Dec.  Hugh Hudson will take over as SXT Chief observer until
the New Year holiday and Nariaki Nitta will act as SXT Chief Observer in
the new year.


SOLAR ACTIVITY

     The solar activity was pretty low during weeks 48 and 49.  The largest 
flare was a C9.7 seen on 6-Dec-93.   Recently, a coronal hole has occupied
much of the northern solar hemisphere.  


SCIENCE PROGRESS

     One of the most interesting highlights is that S. Masuda, a graduate
student of Dr T. Kosugi has recently completed an empirical study of the 
alignment between HXT and SXT as a part of his thesis work.  His results are 
very encouraging and provide good alignment between HXT and SXT, taking
into account the small roll angle of SXT relative to the spacecraft.  He
has now compared in detail the X-ray emission of SXT and HXT for about
ten flares.  In one case, the hard X-ray emission appears to come from
above the apex of the soft X-ray emitting loop (in the cusp region).  If
this is the case, it may be an example of hard X-ray emission from the
reconnection site.

     During the week of 29 Nov - 3 Dec there was a bright point campaign
which was organized by Karen Harvey involving Kitt Peak, BBSO, and Mees. 
Solar activity prevented us from operating the SXT with its special
bright point observing table for two days, and a power outage at ISAS
prevented us from loading the special table on a third day.  Despite
this, SXT bright observing mode was used on three days between KSC
Passes 2 and 4 on 30 Nov and 1 Dec and between Pass 3 and 4 on 3 Dec. 
The region that was selected on 30 Nov produced a few bright points. 


SXT OPERATIONS 

     There were several ground-system problems during the week of the
bright point campaign.  There was a scheduled power outage at ISAS on
the first potential day of the campaign, and thus, we were unable to
prepare or load SXT tables on that day.  During week 48, Yohkoh data
received at KSC downlinks on two days were mis-labeled as ASCA data
during their transmission to ISAS.  As a result, the Sirius temporary
files were not created and auto_toban2 could not reformat the data. 
This situation made it difficult for the SXT Chief Observer to plan the
sequences.  On 3 Dec, the mainframe # 1 computer at ISAS had to be
rebooted during the time of SXT operations, causing the delay in the
observing campaign.