2002 April 1-June 30 AIPS Quarterly Report

Distribution and Versions - The 31DEC02 version of AIPS now has been in routine operation for six months, under the new cvs configuration for the midnight jobs. Unfortunately, counts of "fetches" of the AIPS versions still are disabled due to complexities associated with local cgi scripts and a lack of resources to fix the problems.

Key Developments -

• A memo comparing the results of the KRING and FRING tasks for fringe-fitting has been released as AIPS memo No. 107. The two tasks give similar results on both high- and low-signal/noise cases. In many instances, it appears that KRING runs faster, typically by factors of 1.5 to 4.
• The VLBA data-calibration utilities have been improved and debugged further. In particular, VLBALOAD and VLBAFIX include many more of the bookkeeping tasks necessary to deal with various peculiarities of correlator output data.
• The VLBA data-calibration pipeline has been completed for basic VLBA data between 1 and 15 GHz observation frequency. It was demonstrated successfully at the Synthesis Imaging Summer School, and is intended to be incorporated into AIPS releases later this year. Future developments will focus on more complex observations, such as polarization, high frequency, and those with some "extra" antennas such as the VLA, GBT, and Effelsberg.
• A variety of adjustments have been made to IMAGR and related tasks, largely in order to make wide-field imaging and multi-resolution Cleaning more robust. Included are better handling of boxfiles, a bug fix in steering the multi-resolution algorithm, better defense against selection of a field with inadequate flux or bad window parameters, and an increase in the size of the Clean box arrays.
• FILLM and WETHR were modified to provide more control and insight into opacity corrections that were made to the data. A seasonal opacity model was added to the one that is derived based on the actual surface weather data, and the user given the capability of combining the two with any relative weighting (default is 0.5 each). INDXR also was changed to make use of the weather information in computing CL tables.
• An "adverb pass back" capability was added in order to permit adverbs to be passed back to AIPS from the outputs of running various tasks.
• UVCON was modified to allow a source model for simulations to be multiplied by various types of antenna primary beam, and to use different coordinate systems for the antenna positions.

Goals for Q3 2002 -

1. Continuing maintenance and user support, including systems support.
2. Resurrect the monitoring of fetching of copies of 31DEC01 and 31DEC02.
3. Add a guide to low-frequency, wide-field imaging as a Cookbook appendix.
4. Improve interactive editing capabilities.
5. Incorporate VLBA calibration pipeline into AIPS midnight job release.