To: Phyllis Jackson From: Eric Greisen Date: "1 April 1994" Subject: Quarterly Report on AIPS (1994 Q1) The 15JAN94 release of "Classic AIPS" was made available only a little more than a month late. By the end of March, we had shipped the release to 44 institutions, 9 by magnetic tape (of 4 kinds) and 35 by electronic file copies. The installations of the new release appear to be occurring without difficulty. In addition, two sites have subscribed to the 15JUL94 release that is under active development by the AIPS Group. The copies of AIPS at the California Institute of Technology and the Center for Astrophysics are now updated automatically and electronically on a nearly daily basis. These two institutions have a particular need to track the latest developments in software for the VLBA Correlator and calibration. There were three new tasks added to AIPS in this quarter. MAPBM is used to make images of the single-dish beam in all four Stokes polarizations using holography-mode observations. Images made from VLA snapshot observations may then be corrected for the (considerable) polarization of the single-dish beam using VLABP. This task does not work on images from multiple scans because of the rotation of the single-dish polarization with hour angle. The third new task, MODVF, is used to model the velocity field of galaxies observed, particularly in neutral hydrogen. It uses a tilted ring model to describe the warping of the plane of the galaxy. In contrast to most existing software of this kind, MODVF allows the user to describe the warp using parameters which are fully independent of the location of the observer with respect to the galaxy. Much effort during the quarter was expended on the task FITLD which translates VLBA correlator data into AIPS for calibration and imaging. It was made more robust for handling multiple output data streams, for cleaning up on termination, and for handling and correcting IM and other tables on input. VLBI calibration tasks were improved and corrected, including adding additional calibration-table corrections to CLCOR, generalizing the calibration using auto-correlations in ACFIT, adding geometric delay computations to the rebuilding of calibration tables in INDXR, and improving the display of calibration tables by SNPLT. The tape indexing task PRTTP was generalized to handle unknown formats reasonably and was cleaned up to report all errors on the printer and to continue functioning whenever possible despite various error conditions. The port to the Linux operating system on personal computers was completed, including the cleaning up of a poor, but widespread coding practice through large parts of AIPS. File: /home/primate/egreisen/AIPS/reports/QRep94a.TXT