REPORT FROM ISAS  11/09/91  (0227 JST)
L. Acton

With the passage of NOAA active region 6891 things have quieted down a
bit on the sun and around here.  This was a lovely active region and
data were collected which will bear combined analysis for a long time. 
Even though the data flow through DSN was not fully operational some
excellent time sequences were obtained.  Some quite good flare coverage
has been obtained, especially on the X1 flare of 10/24 which was also
well observed by the Mees Observatory team.  Observations of coronal
developements for which the flare flage is not triggered are still badly
broken up by telemetry data gaps but this condition is expected to
improve as DSN coverage becomes routine. 

On 11/05-11/06 the Yohkoh spacecraft was off pointed to the west to show
more corona on the SXT CCD.  On the 2.7 sec exposures the x-ray corona
was clearly visible to almost 1 solar radius above the limb.  As luck
would have it the off pointing at about 2045 UT on 11/05/91 coincided
with the middle of our best filament eruption (CME??) event yet.  This
began in soft x-rays sometime around 1900 UT on 11/05/91 in the SE
quadrant.  A dark filament is clearly visible on the BBSO h-alpha image
at 1649.  I predict that it erupted sometime around 1900.

SCIENCE magazine is going to feature an SXT image in the news section of
the next issue.  The image was prepared as a composite of 3 exposures
spanning 10 ms to 2.67 sec here at ISAS and transferred as a FITS format
time to SCIENCE in Washington for recreation and printing in false color
in the magazine.  It will be fun to see how it turned out.  I understand
that this is the first time that SCIENCE has received a picture this
way. 

A check of both wide and narrow band optical images this evening showed
that both are continuing to drop in sensitivity at about the same rate
as the last two weeks.  However, it is becoming apparent that this rate
is about 40% less that the decrease during the first few weeks of the
mission.  At this time the sensitivity has dropped to about 66% of the
first image on 9/03/91. 

Mons is back from California after having helped Stanford and Berkeley
get the SXT software up and running.  He will shortly be distributing
the first week of Yohkoh data (including the 10/24 flare) to the co-i
institutions as a sample to begin to work with.  Distribution of
reformatted Yohkoh data has been delayed because of the unavailability
of processed Yohkoh attitude information.  We hope that these necessary
data will be available soon so the data can begin to flow.