; FILLR ;--------------------------------------------------------------- ;! reads old VLA on-line-system tapes into AIPS ;# Task Tape UV ;----------------------------------------------------------------------- ;; Copyright (C) 1995, 1999 ;; 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 ;----------------------------------------------------------------------- ;--------------------------------------------------------------- FILLR LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC FILLR Task to read a VLA MODCOMP archive tape. UNLESS YOU HAVE VERY OLD DATA, YOU WANT TASK FILLM INTAPE Tape drive number NFILES Number of files to advance DOALL If true take all sources. OBJECT Source name BAND Frequency band (P,L,C,X,U,K) QUAL Source qualifier -1=>all VLAOBS VLA obs. pgm. name ('AZ99') VLAMODE VLA obs. mode (' '=normal) NPOINTS Max. number of 1000's vis BIF 0.0 2.0 Start IF to read, 0 => all EIF 0.0 2.0 End IF to read, 0 => BIF+1 OUTNAME Output UV file name (name) OUTCLASS Output UV file name (class) OUTSEQ -1.0 9999.0 Output UV file name (seq. #) OUTDISK 0.0 9.0 Output UV file disk unit #. DPARM User options. 1 => Avg. time (seconds) 2 => max. IF flag allowable (default 3) 3 => max. sum of IF flags per baseline (def 4) 4 => Control dropping of shadowed data < 0 => no shadow check 0 or < 25 => 25 m limit > 25 => Shadow limit is DPARM(4) in metres 5 = no. channels (see HELP) 6 => Subarray number 0=>any. 7 => reference date offset. 8 => CL table time incr. min 9 => No. files to read. ---------------------------------------------------------------- FILLR Task: This task will create an AIPS uv data file and fill it by reading selected data from a VLA MODCOMP archive tape. NOTE THAT THIS TASK IS FOR DATA IN A FORMAT NOT WRITTEN SINCE THE END OF 1987. ALL OF THE ARCHIVE DATA WERE CONVERTED TO THE NEW FORMAT AS WELL, SO FILLR APPLIES TO DATA TAPES EXPORTED FROM THE VLA PRIOR TO 1988 (OR AT LEAST PRIOR TO THE ARCHIVE UPGRADE). FOR MORE RECENT TAPES, USE FILLM. Adverbs: INTAPE.....Tape drive from which to read data. NFILE......Number of tape files to advance before reading. DOALL......If DOALL is true, a multi source output file will be written with associated SoUrce, iNdeX and CaLibration extention tables. OBJECT.....Name of the desired source. blank=>first found. BAND.......Name of desired frequency band i.e. 'P','L','S', 'C','U','X' or 'K'. Blank => first found. QUAL.......Source qualifier number, -1=>all. VLAOBS.....The name of the observing program on the VLA, e.g. 'AZ99'. blank=> first found. VLAMODE....The VLA observing mode. Normal interferometer mode is ' '. (2 characters). NPOINTS....The maximum number of 1000's of visibilities. The output file will be contracted if the guess is too large but the file cannot be expanded. If the guess is low by more than 20% then FILLR will stop when the file fills up. BIF........Start IF to read, 0 => all IF's EIF........End IF to read, 0 => MIN (BIF+1, NIF) where NIF is the number of IF's present in data base OUTNAME....Output UV file name (name). Standard behavior with default 'source name'. OUTCLASS...Output UV file name (class). Default 'UVDATA' OUTSEQ.....Output UV file name (seq. #). 0 => highest unique. OUTDISK....Disk drive # of output UV file. 0 => highest disk with space for the file. DPARM......User options. (1) Averaging time in seconds. If 0 no averaging will be done. NOTE: the program subtracts 2 seconds from this value. (2) Maximum IF flag allowable from the online system. 0 => 3 (3) Maximum sum of IF flags per baseline, 0 => 4 (4) Control shadow checking < 0 => don't drop shadowed data 0 or < 25 => drop data with 25 metre limit >= 25 => drop data when they are shadowed by an amount in the range 0 < SHADOWED <= DPARM(4) where DPARM(4) is in metres (5) if spectral line data for a given source/band with more than one number of channels is present in the data one may be specified by DPARM(5). 0 => first encountered. (6) Subarray number desired. 0=>first found. (7) Reference date offset (8) Time increment (min.) for CL table entries. 0 => 5 min. (9) FILLR will attempt to read up to DPARM(9) files and write to a single output file. 0 => all. ---------------------------------------------------------------- FILLR: Task which creates and fills an AIPS uv data set using a VLA MODCOMP archive data tape. DOCUMENTOR: W. D. Cotton, NRAO. RELATED PROGRAMS: All AIPS uv programs PURPOSE FILLR reads a VLA MODCOMP archive format visibility tape, creates and fills an AIPS uv data base. Since such a tape may contain data for a number of observing programs and sources the user must specify the data that he/she desires. COMMENTS The tape must be properly mounted and the correct density specified. This is most easily done using the MOUNT command in AIPS. When through reading the tape and no other tape processing is anticipated, use DISMOUNT to free the tape drive for other users. NPOINTS: This adverb specifies the maximum number of UV points which will be transferred to disk from tape. The value of NPOINTS is 1000 times the number of points to be transferred, and should also be set at the lowest multiple of 1000 higher than the number of points to be loaded to disk (e.g., NPOINTS=17 for a data set containing 16,201 visibility records). There is a 20% leeway in NPOINTS. If you set NPOINTS=17, the UVLOD will read up to 20,400 uv points before terminating. A warning message is given if more data are found. OUTDISK: Make sure there is enough space for the source data on the specified OUTDISK (see below). This is especially important is many large data bases will be written onto the disk. DPARM: (1) The data are averaged by averaging all unflagged data with time tags within the specified period after the first record in a given integration. The time tags, u, v, w etc. for each visibility written will be the average for the integration irregardless of the flagging; that is the u, v, w may not correspond to the true weighted average. Two seconds are subtracted internally to keep the integration times produced from being one more MODCOMP integration than intended. (2-3) The online system assigns a flag level to each IF in each integration period. DPARM(2) sets the maximum allowable flag level for a give IF and DPARM(3) sets the maximum sum if the IF flag levels allowed for a correlator. Increasing flag level values correspond to increasingly serious problems. (4) Data for which one antenna shadows another antenna is normally rejected. Crosstalk and solar interference normally are serious problems in this case. If DPARM(4) is greater than 0 shadowed data will be passed. (5) Modcomp tapes may contain data for a given source/band with different numbers of spectral channels at different times. Such data must be kept in separate files. DPARM(5) is used to specify which set of data is desired by specifying the number of channels. If DPARM(5) <= 0 then the first set encountered will be used. The default will have the desired action in almost all practical situations. (7) If data from several tapes are to be concatenated they must be read by FILLR independently and concatenated by DBCON. This data should all have the same reference date. DPARM(7) is the number of days to offset the reference date. Example: DPARM(7) = -1 causes FILLR to use the day BEFORE the first day encountered as the reference date. (8) A dummy CL table is created with appropriate default values. DPARM(8) gives the time interval between entries. 0 defaults to 5 min. (9) Modcomp tapes frequently contain several files. Using DPARM(9) the number of files read can be controlled. The default (0) is to keep reading the entire tape; this may produce unpredictable results if there are other types of files following the Modcomp records. Labled tapes must be read one file at a time and then concatenated via DBCON. EXECUTION TIMES: The execution time depends on the location on the tape of the desired data. If the user starts reading from the beginning of the tape, required CPU time may be only 10 seconds for data near the beginning of the tape and several minutes for data close to the end of the tape, with a roughly linear relation in between (i.e., most of the CPU time for a data set not at the beginning of the tape is spent reading through the tape to find the desired data set). In an otherwise empty VAX 11-780 it takes about 5.5 min to load 50,000 visibility points (all four polarizations) DISK SPACE: The size of a data set loaded via UVLOD is linearly proportional to the number of UV records in the data. The ratio of disk blocks to visibility records is roughly 1:7, so a data set containing 50,000 visibility records will occupy approximately 7,000 blocks of disk space. Be sure there is enough space on OUTDISK to hold the data.