SXT Status Report
                       21 August - 10 September 1995 (Weeks 34, 35 and 36)
                                  ---------

                                Nariaki Nitta
                                  10-Sep-95

This reporting period included an important day.  On 30 August, we 
celebrated Yohkoh's four year anniversary.  However, a well-justified
party will be absorbed by the banquet during the workshop that commemorates
the retirement of Prof. Hirayama.  Let me remind you that he is SXT-J PI.
The workshop has been organized mainly to learn what he has achieved as
the only Japanese whose paper appeared in Solar Physics Volume 100.

SPARTAN was launched at long last.  

Before arriving at Narita, I had expected nice heat waves in Japan, but 
I was too late to enjoy summer.  Now we have perfect autumn weather that 
induces us back to research.  With such visitors as Ron Moore (MSFC) and
Kevin Reardon (UH), we enjoy scientific discussion based on real data.


SOLAR ACTIVITY

The Sun was not too inactive during these three weeks.  Active regions
7901, 7902, 7903 and 7904 were present, producing several B-class and a 
few C-class flares.  Many X-ray bright points were discernible all over
the Sun.

Although the appearance of new-cycle regions were announced and 
broadcast in the NPR/Morning Edition by Hal Zirin (his comment "we do
not know much about the Sun, ha, ha, ha" was more impressive), it is
not universally accepted.  The SXT also saw these reverse polarity regions,
but they did not appear to be different from other regions.  


SXT INSTRUMENT STATUS

The straylight increased by about a factor of three on 16 August, because 
of another rupture of the entrance filter.  However, the straylight level
has been stable since then and is still well within the range of 
correction.  While we offpointed the satellite to observe the extention
of the corona above the western limb, a third (northeast) pinhole was seen 
in the images in the thin aluminum filter.  It is likely that this is not 
due to changes in the analysis filter, but further investigations should be
made.  


CALIBRATION STATUS

Currently, calibration efforts are being applied towards continuing with 
the various established calibration procedures, and quantifying the recent 
increase in the stray light. Much progress has been made in this direction 
in very little time.  Quick application of an offpoint terminator (sunset) 
image indicates that the thin aluminum filter images need closely matched
terminators for straylight correction.  This situation is same as before.


PASS CONFLICTS

Due to conflicts with ASCA, we lost a total of 9 passes in Week 34, 7
passes in Week 35 and 11 passes in Week 36.


SCIENCE

Because of an increased number of scientists, scientific activities
were quite high.  Here I confine myself to recent achievements.

SXT observations in early September resulted in an interesting discovery.
A special observing sequence was created by Hara and Koutchmy, with the 
help of Weber and Hudson, to look at N polar plumes and transient spikes. 
A version of this table was developed for the SPARTAN 201-3 support 
observations, and the test data have now been reduced by K. Reardon.

The result of this interesting observation was the detection of no less
than four X-ray jets over a two-orbit period, three of which were so 
faint that they would not have been detected without a careful dark
subtraction.  Each of the jets was associated with a bright point, 
leading Shibata to the reasonable conclusion that ALL flaring bright 
points will have jets associated with them.  This observation may provide 
a link between the Yohkoh/SXT X-ray jets and the plumes studied at many 
wavelengths earlier.  This has implications for coronal heating and the 
formation of the solar wind.


SEMINARS

23 August: 
G. Roumeliotis (Stanford University): "IRIS: An Algorithm for the
Reconstruction of SXT Images"

6 September:
R. Moore (NASA/MSFC): "Sheared Core Magnetic Fields, Flares, and 
Coronal Heating"


PERSONNEL

Hugh Hudson returned from GSFC.  George Roumeliotis was here for five
days.  Kevin Reardon arrived for three-week stay, Nariaki Nitta arrived 
for one-month stay and Ron Moore arrived for three-month stay.  Keith 
Strong will be here only during the Hirayama workshop (11-12 September).


Week 34 Tohban:
   SSOC: Y. Hanaoka and S. Ueno
   KSC:  J. Sato and K. Hori
SXT Chief Observer:
   M. Weber
SXT Systems and Data Engineer:
   G. Slater

Week 35 Tohban:
   SSOC: K. Shibasaki and K. Yaji
   KSC:  K. Hori and M. Nishio
SXT Chief Observer:
   M. Weber
SXT Systems and Data Engineer:
   G. Slater

Week 36 Tohban:
   SSOC: Ta. Watanabe and others (Te. Watanabe, T. Sakao and M. Takahashi)
   KSC:  M. Nishio and S. Nagata
SXT Chief Observer:
   M. Weber / N. Nitta
SXT Systems and Data Engineer:
   G. Slater