27 September 1998
                                                              Hugh Hudson 

              SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN

                 CHIEF OBSERVER'S REPORT for Week 39
                        21-Sep-98 to 28-Sep-98

GENERAL

Yohkoh SXT has performed with no difficulty this week. There is
virtually no technical news whatsoever.

There were two M flares, interesting interconnecting loops, a beautiful
sigmoid that did not erupt on the disk, and other goodies. The M flare
of Sep. 23 was well-predicted by McIntosh on the basis of flux emergence
in AR 8340. It has led to a major magnetic storm, too bad that SOHO has
not recovered fully. At the time of writing we have not seen all of
the Yohkoh data (DSN/Canberra).

J.-P. Wuelser has continued to work with improvements to the Yohkoh 
image coalignment software. A new program, SHOW_HXAFIDS, is now running
on the QUICK cron job. It shows the SXT sun-center positions with
the HXA "forbidden zones" of limb exclusion by fiducial marks.

SXT SCIENCE 

For Web material see

Current Week: http://www.solar.isas.ac.jp/sxt_co/SXTweekly.html
Index:        http://www.solar.isas.ac.jp/sxt_co/index.html

The science nugget (week 98_39) shows...

CAMPAIGNS

Louise Harra-Murnion (TRACE/Norikura)

PERSONNEL

No changes

SEMINARS

24-Sep-98:

J.-P. Wuelser (LMSAL): Loop-top flare sources observed with EIT.

H. S. Hudson (SPRC): HESSI Overview: Why image at high energies?


                        TABLE PLAN, WEEK 40 
                       (28-Sep-98 - 4-Oct-98)


We look forward to synchronizing again with SOHO. There
seem to be no interesting coordinated observations planned
for this week.

________________________________#_______________________________

JST Day     	UT Start Time      Pass    Table ID

Monday          27-Sep-98 23:54     3      980927 P3 ARS1 DARKCAL
Tuesday         28-Sep-98 20:45     2      980928 P2 ARS1 DIF 
Wednesday       29-Sep-98 21:02     2      980929 P2 ARS1 STD
Thursday        30-Sep-98 19:37     2      980930 P2 ARS1 STD
Friday           1-Oct-98 19:54     2      981001 P2 ARS1 STD 
Saturday         2-Oct-98 20:11     3      981002 P2 ARS1 STD 
Sunday           3-Oct-98 18:45     2      981003 P2 ARS1 STD 

Note that the naming convention uses the UT day number of the
first pass of the day.

This plan may change during the week. This plan differs from the
one sent around last week in that we've added a second table on
Tuesday.


Continuing requests:

KSC & SSOC Tohbans: If any KSC passes are likely to be cancelled (for
example due to a typhoon) or an SXT table cannot be uploaded for some
reason, please telephone and e-mail the Chief Observer immediately.
(sxt_co@isass0.solar.isas.ac.jp, copy to sxt_st@flare2.solar.isas.ac.jp). 

SSOC Tohban: On the weekly visible diagram, please mark the official
five passes first and then cross out those passes that will be given to
other satellites.  That way we can keep the numbering straight in the
Yohkoh software system.

SSOC Tohban: SXT operations do not currently include terminator off- 
pointing. It is unnecessary this week to ask the SXT Chief Observer
for terminator off-pointing information.

KSC Tohbans: In general flare mode supersedes table upload, ie if a
flare is in progress please do not upload a new table, and contact the
chief observer. Normally it is OK to go ahead with the planned table
without change on the next pass, if it is available. Chief observers
should keep an eye on this.