2002 January 1-March 31 AIPS Quarterly Report
Distribution and Versions - The 31DEC01 version of AIPS was frozen and has been released. The
move to Socorro of the midnight job and master version for 31DEC02 has been completed, and the
midnight job now runs under the Unix "cvs" utility. At the moment, counts of "fetches" of the AIPS
versions are disabled due to complexities associated with the move of the master copy and local cgi scripts.
Key Developments -
- In association with the moving of the code to Socorro, the master AIPS world-wide web pages
also have been moved to Socorro. Most critical links and scripts work. Some dependence on cgi
scripts specific to Charlottesville has been found, causing occasional problems. The Charlottesville
version of the AIPS web pages has been removed except for re-directs to the Socorro versions.
- Systems activities associated with midnight jobs and installation questions from users (general
installation, multiple machines, remote TV displays, and so on) take an ever-growing fraction of
AIPS programmer time, currently estimated at 50% of a person-year. With dedicated systems
assistance no longer available for AIPS, this time is taken away from applications programming, and
results in delays in meeting applications targets. The Socorro Computer Division occasionally helps
out on questions that involve both AIPS issues and more global computing system issues.
- The AIPS configuration tasks (e.g., CONFI and UVCON) have been used by the AIPS group to
develop tentative arrangements for the E configuration (new compact configuration) of the VLA,
that is proposed as part of Phase II of the EVLA project. The configuration work has been used to
determine the locations of the fiber-optic runs in the center of the array for EVLA Phase I, so that
the fiber locations do not impact possible future addition of the E configuration. For possible
simulations of SKA stations using multiple antennas, CONFI now has the option of multiplying the
array beam by the antenna primary beam, in order to optimize sidelobes.
- A new task, RMSD, was added to compute the rms in a two-dimensional moving window through
each plane of an image. This enables noise to be determined in different planes in the vicinity of real
signals, and can be used as input to XMOM in order to compute image moments with useful flux
cutoffs. Since RMSD operating on each pixel is a very time-consuming task, the user-controllable
XINC and YINC parameters have been included in order to operate on subsets of all the pixels.
- Continued work took place on the VLBA data-reduction utilities. This included fixing some default
parameters, determining whether data sorting and indexing are necessary (and doing them if
needed), and combining the table-merging steps into the data-loading utility. A new version of
Appendix C of the AIPS Cookbook, covering VLBA data calibration, has been installed. This
version now describes the VLBAUTIL procedures as the first choice, with the more complicated
AIPS tasks considered as "backups" for those who want to adjust more parameters.
- A new task, WETHR, has been added. This task processes and plots weather data in various ways,
and also can be used to create flags based on weather parameters.
- Various changes have improved the capabilities of wide-field imaging, or corrected previously
erroneous documentation. The new task BOXES allows a box file to be inserted (e.g., with NVSS
sources) so that low-frequency, wide-field maps can easily clean out the many sources in a field.
- The Cookbook has been revised. It includes a new guide to VLA high-frequency data reduction.
- The memo comparing FRING and KRING has been held up by some uncertainties about the
statistics of the distribution of phase errors. These uncertainties now have been resolved, and the
memo should be released early in the 2nd quarter of 2002.
- A new package of procedures, WRTPROCS, has been developed to enable writing and reading of
files to and from disk. The verb SG2RUN enables save/get files to be copied to text files for later
use as RUN files (e.g., on a computer of another architecture).
Goals for Q2 2002 -
- Continuing maintenance and user support, including systems support.
- Resurrect the monitoring of fetching of copies of 31DEC01 and 31DEC02.
- Add a guide to low-frequency, wide-field imaging as a Cookbook appendix.
- Code new Gaussian fit error tests into programs such as SAD and JMFIT.
- Complete and issue the memo comparing KRING and FRING.
- Support data-reduction workshops at the Synthesis Imaging Summer School..