SXT REPORT FOR WEEKS 39-40 ; 19 Sep 1993 - 3 Oct 1993               

GENERAL STATUS

     During part of the past two weeks we conducted a joint observing
campaign with Norikura Observatory.  Hirohisa Hara went to Norikura to
assist in the observations while Toshifumi Shimizu acted as the SXT
chief observer.  The weather was generally poor during these past 
two weeks, but there were two good days of observations.  Norikura
made observations in Fe X, Fe XIV and Ca XV lines (the standard
red, green and yellow lines) of AR 7590 region while it was on the
East limb.

     The SXT continues to work well.  The spacecraft is working well
and the pointing accuracy seems to be improved since switching from 
the Y gyro to the Skew gyro.


PERSONNEL

     Hugh Hudson and James Lemen returned to Japan at the end of last
week after making short trips to the States.  Greg Slater and Sam 
Freeland returned to the States during this interval.  Mons Morrison
arrived for a 4 week visit at the beginning of last week.  Frante Franik
arrived from Prague last week and will spend 4 months at ISAS as a visiting
fellow of NAOJ.  Louise Harra (MSSL) arrived this week to begin a 1-year 
tour of duty as a part of the BCS team.


SOLAR ACTIVITY

     After many weeks of low solar activity, the GOES level finally
increased with the appearance of AR 7590.  This region has produced
one M flare and numerous high-C flares.  A new region has now appeared
near the east limb AR 7592.  Because of this increase in activity (the
Goes level is currently at a high-B level), we have decided to postpone 
the Bright Point collaboration with NSO/KP.  Instead, NSO/KP will make 
He I spectroheliograms and magnetograms of the same region as Yohkoh.


SCIENCE PROGRESS

     Perhaps the main science achievement this week is that we obtained
joint Norikura and SXT images.  A combined analysis of this data
set should yield a differential emission measure model for the active
region.  This was the third time that this joint observing campaign
has been tried.  The previous two attempts failed because of poor weather.
Hara san has already performed a preliminary comparison.  The images 
obtained in the hottest (Ca XV) line shows a strong correlation with the 
X-ray observations obtained with the Al.1.

     Mons Morrison and Jean-Pierre Wuelser modified the SXT software that 
make use of the spacecraft gyro information for image registration.  
This was necessary because of the decision to change from using the Y gyro
to the Skew gyro.  

SXT OPERATIONS

     The SXT operations went very smoothly this week and there were
no significant problems to report.  Loren Acton performed an investigation 
on the diffuser images to study the variation of the "ghost images" (which
are places where the CCD has received large X-ray exposures).  Loren
wanted to determine if the ghost features fade with time from the 
increased UV flood.  

     Loren concluded that the ghost images appear to recover at least
partially, but not fully.  The "worst" ghost image shows little evidence
for improvement with time.  Although the study is inconclusive at this
point in time, it was decided that we will make no change to the UV flood
morning patrol interval.


                                                  James R. Lemen
                                                  4 Oct 1993