;--------------------------------------------------------------- ;! Calculate ionospheric delay and Faraday rotation corrections ;# PROCEDURE VLA ;----------------------------------------------------------------------- ;; Copyright (C) 2006; 2010 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- VLATECR LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC VLATECR Procedure to calibrate ionospheric delay INNAME Input UV file name (name) INCLASS Input UV file name (class) INSEQ 0.0 9999.0 Input UV file name (seq. #) INDISK 0.0 9.0 Input UV file disk unit # SUBARR Subarray to correct (0 => all) VLATECR is defined in the VLAPROCS run file. ---------------------------------------------------------------- VLATECR Type: Procedure Use: Automatically download IONEX files needed to correct the atmospheric Faraday rotation with TECOR. Then runs TECOR. See EXPLAIN TECOR for more information on this correction. To do the automatic download the system must have one of the following commands: wget, curl or ncftpget, and an NX table. VLATECR is defined in the VLAPROCS run file. Adverbs INNAME.....Input UV file name (name). Standard defaults. INCLASS....Input UV file name (class). Standard defaults. INSEQ......Input UV file name (seq. #). 0 => highest. INDISK.....Disk drive # of input UV file. 0 => any. SUBARR.....Subarray to correct. 0 => all. ---------------------------------------------------------------- VLATECR: Procedure that corrects the atmospheric Faraday rotation using TECOR. This procedure automatically downloads the IONEX files from the CDDIS archive. DOCUMENTOR: Amy Mioduszewski RELATED PROGRAMS: VLAPROCS, TECOR VLATECR is designed to make the use of TECOR easier. It uses the header and the NX table to calculate what files to download from CDDIS. It uses the CDDIS site in the US (cddis.gsfc.nasa.gov) and downloads the jplg or codg version of the IONEX files. Then it runs TECOR using these files. For simplicity (files from multiple days must to have the same prefix), all the files are renamed with the jplg prefix. The IONEX files are left in the /tmp area of your computer, so you can copy them for your records or ignore them. VLATECR uses APARM=0, (i.e., it does not do the dispersive delay and does not adjust the direction of the Faraday rotation). See EXPLAIN TECOR for more information. NOTE: The IONEX files can take up to a week to be available at CDDIS. This procedure is defined in VLAPROCS, type RUN VLAPROCS to load VLAPROCS. To run VLATECR: 1) The dataset must have a correct observation date in the header; if it is wrong correct it with PUTHEAD. -> there is a weak test on the validity of the observation date; the observation year must be <= to the creation year. 2) The dataset must have an NX table; run INDXR to create. 3) The system must have one of the following commands: wget, curl or ncftpget. VLATECR will test for the existence of these commands in the order given above and will use the first one it finds. Mac OS - will probably have curl; wget and ncftpget seem to be available in Fink. 4) /tmp directory must exist on your computer 5) Your computer must allow link to the Internet, some computers may have firewalls such that the above commands exist, but will not work.