30-Aug-2005

The default RHESSI subcollimator response table has been updated.  This
is the file that contains the grid transmission and modulation
parameters as a function of energy and angular offset.  Although the
change will result in a barely perceptible change (at the ~1% level) for
most imaging and spectroscopy applications, it will provide a more
significant improvement for visibilities, demodulation, and for any work
on time scales less than 4 seconds.

The updated table incorporates improved values of grid phases (based on
conjugate visibilities) and improved values for grid tilt for
subcollimators 3,4,5 and 6 (based on demodulation tests).

The new file (SRT_20050829.dat will be added to your ssw as
hessi/dbase/grid_resp/SRT_20050829 as part of the next ssw update.  If
you need to redo analyses with the current default subcollimator
response table (SRT_20040706.dat), it can be invoked with the srt_file
parameter.  In case of doubt, you can see the name of the file that is
actually used in the IDL output log.

For non-solar analyses at large offsets (to +-2.5 degrees), a much
larger version (~28MB) of the new table can be found at
http://sprg.ssl.berkeley.edu/~ghurford/SRT3-7p.dat

Please let me know if you have any questions or encounter any anomalies.

gordon