AIPS: Third Quarter 2003

Key Developments

1.   FILLM, the task that reads VLA archive data into AIPS, was corrected to account for the change in array center when the Pie Town antenna is included. The "real-time" version of FILLM now reads data from the mirror disk area and can begin reading with data taken one or more days previously.

2.   Plotting tasks may now draw colored lines using the full range of colors under task control. At present this is used, optionally, to display the polarization angle, to contour multiple spectral channels on top of each other, and to separate multiple IFs or spectral channels in plots of visibility data.

3.   The pipeline reduction procedure set for VLA data, called VLARUN, was cleaned up and its use encouraged.

4.   New tasks to fit and correct the residual zenith delay (DELZN) and to account for its effect on calibration of other sources (DFCOR) were written.

5.   The task FIXWT which resets weights depending on actual visibility data rms was completely rewritten and may now be useful. The task MSORT designed to sort visibility data which are nearly in the correct order was greatly improved through the use of more memory and through the addition of an alternate, brute-force algorithm.

6.   The installation script was changed to make the setup for "midnight jobs" more robust and to ask the installer whether the machine is a "laptop," with the answer controlling how later steps are handled.

Goals for Fourth Quarter 2003

The following efforts are expected:

1.   Continue user support and bug fixes, as the major portion of AIPS effort.

2.   Add various suggestions from Australian users to enable them to run the midnight job.

3.   Make a variety of improvements to the VLBA calibration task APCAL including the use of the available weather data, improved interpolation options, and better opacity fitting and plotting.

4.   Have the FITS readers support the new World Coordinates System nomenclature where possible and allow FITLD to read more than one VLBA correlator data file from disk.

5.   Investigate the use of overlapping solution intervals to minimize lobe ambiguities in fringe fitting.

6.   Continue the moderate-term project to explore improved troposphere calibration.

7.   Add Tsys values for a single VLA antenna into the calibration data supplied with VLBA correlator output.

8.   Test and enhance AIPS performance on MacIntosh computers with the G4 and G5 processors.