SXT Status Report
                     July 21, 1998 - August 9, 1998
                             (Weeks 30-32)

                    H. Hudson, N. Nitta, D. Alexander


SUMMARY

Activity was low to moderate, and SXT has operated well. Joint observing
campaigns with ground-based observatories and TRACE produced interesting
results.

SOLAR ACTIVITY

The GOES level (see the plots, for example, on our weekly SXT Web
pages) started at B4, decreased below B2 (29-Jul-98), and came above
B6 (6-Aug-98), with many C flares and one M flare during the three-week 
interval of this report. AR 8282 reached a peak sunspot area of more than 
500 millionths.

OBSERVING CAMPAIGNS

During these three weeks we carried out several joint observations with TRACE,
including one centered on Hida Observatory observations of emerging flux.
Please see "finger campaign@isass0.solar.isas.ac.jp", also available
on the SXT home page at 
http://www.lmsal.com/SXT/html2/First_Light.html#ops_plan.

We will be maintaining a Web site giving information about the Whole Sun
Fortnight observations:
http://www.solar.isas.ac.jp/~alexande/WSF/observations.html.

SXT INSTRUMENT STATUS AND CALIBRATION ACTIVITIES

The installation of new computers at ISAS has resulted in some confusion of the
databases. Operations has not suffered, but we have seen some problems with
the quasi-real-time data reduction, ie for the movie images. 

We continue to have temporary problems with Yohkoh attitude information,
which also contributes to difficulties with corrections for the quasi-real-time
data reductions. The situation probably requires some software development
and/or the adjustment of the onboard HXA limb threshold, which we will try
to complete by the end of August. 

SCIENCE

The new "science nuggets" consist of:

25-Jul-98: Global CME manifestation in X-rays
 1-Aug-98: Active region seen by SXT and TRACE 
 8-Aug-98: Hida Campaign -- Jet Observed by SXT and TRACE 

The latter two show some of the first direct comparisons of Yohkoh SXT
and TRACE X-ray imaging. 

The full list of science nuggets is on
http://www.solar.isas.ac.jp/sxt_co/index.html,
and the current week is also always kept on
http://www.solar.isas.ac.jp/sxt_co/SXTweekly.html.

OPERATIONS ISSUES

   Week 30: no passes lost due to conflicts at KSC
   Week 31: 1 pass lost to ASCA; 4 passes to Nozomi
   Week 32: 3 passes for Akebono; 1 pass for ASCA

The competing ISAS spacecraft now include Nozomi (the Mars mission) as well
as Akebono, ASCA, and HALCA. Nozomi is in a translunar orbit prior to departure
for Mars via gravity assist.
 
VISITORS AND PERSONNEL

Nariaki Nitta arrived to help with the Hida campaign activities, and prior to
his departure David Alexander arrived to help coordinate the Whole Sun Month
campaign. Hugh Hudson was away from ISAS during most of the period.

SEMINARS

None scheduled.

TOHBANS

Tohbans for Week 30

SSOC : Morita
KSC  : Kumagai, Yamaguchi
SXT_CO: Hudson
SXT_SW: Slater, Shirts

Tohbans for Week 31
 
SSOC : Yamasaki, Kosugi
KSC  : Yamaguchi, Aoki
SXT_CO: Nitta
SXT_SW: Slater, Shirts

Tohbans for Week 32

SSOC : Takanasi.,Takahashi-M
KSC  : Saito-Y, Aoki
SXT_CO: Nitta
SXT_SW: Slater, Shirts