[daip] draft BAAS report

[Eric Greisen]

     The Astronomical Image Processing System (AIPS) software is still
used by most observers to calibrate and image the data from the VLA
and the VLBA.  Since this software is supposed to be replaced by a
more modern package, the manpower in the AIPS project continues to be
reduced.  In the 2000-2003 period, two full-time scientific
programmers and a part-time systems expert were "replaced" by a
half-time scientist-programming assistant.  Despite previously
announced intentions, AIPS is still issued on a fixed release
schedule, which is now annual.  During the reporting period, the
31DEC00, 31DEC01, and 31DEC02 fixed releases were made.  Statistics on
the usage of these is incomplete, especially for 31DEC02.  By
December 2001, 637 copies of the 31DEC00 release had been given away,
449 before it was officially frozen.  Also by that date, 448 copies of
31DEC01 had been given away before it was frozen.  AIPS is now
administered in Socorro at the AOC rather than in Charlottesville.  It
was moved in December 2001 and user access to the development
version, beginning with 31DEC02, was changed from "secure-shell" to
the "cvs" code versioning system.  This has greatly improved the
reliability and simplicity of the "midnight job" which is used by
active AIPS sites to keep their version of AIPS completely current
with the version that is under active development.  That version, now
31DEC03, is updated more or less regularly by over 50 sites.

     During the period, the AIPS group has concentrated on fixing bugs
and making various minor additions to the software.  Despite the
reduced manpower, however, a variety of significant improvements in
the AIPS software have appeared in the reporting period.  They are
described in detail in documents available from the web site at
http://www.aoc.nrao.edu/aips.  The reduction of data from the VLBA has
been greatly simplified by the release of a set of procedures which
perform the basic data reading and calibration operations using
standard parameters.  A VLBA pipeline, which read, edits, calibrates,
and even images VLBA data automatically, has been released within
AIPS.  This procedure is now run on all VLBA continuum experiments
with the results given to the observers along with their raw data.  A
similar pipeline for VLA continuum experiments is being tested.  The
VLA data filling task now uses weather data and tables of antenna
gains to provide users with initial calibration values.  It also reads
data from the disk archive as well as from magnetic tape.  Several new
data editing tasks were written to flag data based on calibration
discontinuities, data decorrelation, weather, and, interactively, on
values outside the range expected by the user.  Imaging algorithms
appropriate to low-frequency data from the VLA also received
attention.  Users may now prepare inputs to do multi-faceted image
deconvolution, correctly accounting for sky curvature and for possible
interfering sources found in user tables and in the NVSS and WENSS
source lists.  The latter are shipped with AIPS in a special compact
form.  AIPS plots may now be rendered in color with a variety of
options controlling line and background colors as well as pseudo and
true color "gray-scale" images.  Lines drawn on top of gray-scale
images change color when the gray-scale exceeds a user-set level.  New
verbs to assist in entering adverb values and new functions to assist
in moving data from Solaris to Linux systems were written.  Tasks may
now set adverb values in the AIPS control program.  AIPS tasks to aid
in the design of new interferometric arrays such as the EVLA, ALMA,
and the SKA have been developed and are in widespread use.  AIPS has
been ported to run on MacIntosh OS/X computers.