REPORT FROM ISAS
From:	L. Acton
Date:	20-Aug-93

SXT STATUS
	The telescope is in remarkably excellent condition for solar
observing after nearly 2 years in orbit.  The level of scattered light
has not changed since November '92  and radiation damage to the CCD
accumulates much more slowly than anticipated.  The reason for this good
fortune is under study.  It may be intrinsic or may be the UV flood--
probably some of each.  SXT mechanisms, electronics, and temperature are
stable.  Contamination continues to accumulate on the CCD (believed to
be water ice) and is removed by periodic heat-up of the CCD to about 20
C.  At this point Yohkoh and SXT can anticipate a long and productive
life as a space solar observatory.
	Yohkoh weathered the storm of the Perseid meteor shower without
effect.

SOLAR STATUS
	The x-ray sun continues to evolve towards quieter conditions. 
During the past 3 weeks one flare reached the M category but today the
GOES plot is riding at the B1 level.  This side of the sun is
essentially covered with quiet corona with only small coronal holes. 
The other side of the sun, 2 weeks ago at least, had very large coronal
holes.  Even at this low level the x-ray pictures are full of detail and
non-potential structures.  We are now collecting long (15 sec and 30
sec) exposures at a 1 for 2 cadence with out standard exposures to
better observe the fainter corona.  There is plenty of margin in the
images to carry on to true solar minimum conditions. 

OPERATIONS
	Dark frame calibrations were done each week.
	An attempt at CCD bakeout last weekend was cancelled because of
computer problems at KSC.  It is scheduled again this weekend.
	The technique for obtaining sunset images for straylight
calibration is being refined and is increasingly successful.  This needs
to be done on an ongoing basis to improve the data base of stray light
correction images.  

NEW PROGRAMS PUT ON LINE.
	A dozen new or improved programs have been put on-line by
Slater, Morrison and me that facilitate the job of Chief Observer and
the evaluation of calibration data. 

CAMPAIGN SUPPORT
1. Emerging Flux Region Campaign (led by T. Sakurai) 3-13 Aug '93.
	Operated in AR tracking mode (ARS2) most of the time.  Two
intervals of PFI-dominant mode for increased time resolution.  PFI
sequence was Al.1-only with one long fixed exposure for production of
extended-dynamic-range movies.  Although much of the period had
unfavorable observing conditions at ground observatories the
coordination was fully effective and several good data sets were
obtained. 

2. Solar EUV Rocket Telescope and Spectrograph (SERTS) Rocket Launch.
	SXT images provided by FTP to the launch site at White Sands
were used in planning the targetting and observing program of this GSFC
rocket experiment.  The rocket launched exactly on time on 17-Aug-93 and
the special SXT observing sequence succeeded perfectly.  This should be
a very valuable data set for studying the chromosphere/corona interface. 

CALIBRATION ACTIVITIES
1.  SXT dark signal response to x-ray damage.
2.  Optical diffuser images.
3.  Straylight contamination with the 8% mask.
4.  Straylight/pinhole correction for Al.1 images.
5.  CCD gain calibration.
6.  X-ray scattering experiment

PERSONNEL
	Slater and Hudson remain at ISAS.
	Acton leaves tomorrow.
	Lemen arrives next week.
	Soon many people arrive in preparation for the Kofu meeting.