SXT REPORT FROM ISAS 10/14/91 (0001 JST)

Now that Sam, Tim and Greg are here we are really moving ahead on
analysis hardware and software improvement.  Tim is very busy 
sorting out the local network to be more user friendly while Tim and
Greg have managed to get the video system up and running and recorded
our first SXT movie on laser disk!!  This is a 40 frame jerky movie
covering the period 9/22 to 9/30/91 with 512x512 images.  I've 
mentioned it before but with the faster projection it is even
more amazing.

On 10/09-10/10 SXT observed a fantastic coronal restructuring on
the SW limb of the sun.  I suspect that it was associated with a
coronal mass ejection (CME) but cannot be sure until we check with
the coronagraph people.  First a set of loops expanded at a rate
of maybe 100-200 km/sec.  Later this turned into an "open" looking
configuration that evolved into "curtain like" shapes.  In the later
phases, the expansion of the system toward the south ran up against
a boundary of some kind and stopped moving in that direction and
became very sharply defined. 

This particular movie is really impressive.  It also shows how much 
sharper the half resolution pictures are as compared to the quarter 
resolution pictures.  When we get DSN coverage in a couple of weeks
to fill in the present data gaps I expect SXT will be able to be 
extremely useful for studying coronal evolution.
On 10/10/91 we also successfully (this time) tried out both the
0.5 sec and 1.0 sec cadence high time resolution mode.  Nothing
of interest happened scientifically but the instrument worked as
planned.  Thanks and kudos to Sam Freeland who figured out the way
to implement the high time resolution modes within the SXTE-U 
microprocessor.

No SXT data will be acquired Monday as the Yohkoh attitude control
system is getting an update of on-board control software and the
spacecraft will be in ACS mode the entire time.

I'd like to close this report with an acknowledgement of the 
commitment and dedication of the SXT team.  The hours that people
have been working are amazing.  John Owens, have no fear that NASA
is getting her $'s worth these days!

Cheers,

Loren Acton