To:      Phyllis Jackson

From:    Eric Greisen

Date:    31 March, 1993

Subject: Quarterly Report of AIPS (1993 Q1)


     The 15APR93 version of AIPS will be released fairly soon, but it
will be delayed until full support for Sun's new operating system is
available in AIPS.  This system is called Solaris and is based on the
Bell System V flavor of Unix rather than Sun's traditional Berkeley
Unix systems.  This is a major change, but should be made easier by
the work we have already done to port AIPS to Hewlett Packard's Unix
system, which is also Bell-based.  Other system-type changes include
modification of the tape handling routines to support a wider variety
of tape devices, handling end-of-information and other conditions more
correctly.  The ability to put all messages from tasks (from any AIPS
computer) into a special message window on the user's workstation
screen has been added recently.  Better control over message
suppression was also added.


     Most of the effort in the AIPS package has been put into
VLBI-related calibration and imaging software.  A substantial
subroutine package has been developed to make AIPS' functions more
modular and more accessible to programmers.  During 1993 Q1, this
package was substantially debugged and had numerous functions added
including self calibration, faster in-core imaging, point models with
corrections for the W term, bandwidth smearing, and frequency errors,
round clean boxes, image interpolation and re-gridding and
polarization-coherent re-referencing of fringe phase, delays, and
rates.  An imaging process similar to Jodrell Bank's difference
mapping (an iterative self-calibration and imaging) was coded using
this package in a task called SCMAP.  Baseline-based VLB fringe
fitting is now available in AIPS usings tasks BLING and BLAPP.  The
antenna-based fringe fitting task FRING can now handle larger amounts
of data in each fit.  The new task CLPLT is used to plot VLB closure
phases rather than VBPLT, but VBPLT can now plot a variety of new
parameters.  Division of compressed uv data by models was corrected
and the speed of MX, CALIB, UVSUB, and FRING was improved by enabling
gridded model computation methods wherever possible.


     New task PASTE inserts (or adds) sub-images into portions of
another image.  A completely revised version of the task GAL to fits
models of galaxy velocity fields was released.  A draft of a proposed
FITS standard for the description of coordinates was released for
comment via the world-wide FITS-exploder and network news.  In
particular, it provides a detailed description of a large number of
projections of spherical coordinates onto the image plane.