AIPS HELP file for VBCAL in 31DEC18
As of Thu Jan 18 16:29:10 2018
VBCAL: Task to multiply antenna amplitude gain factors.
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 #
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 #.
APARM Control info.
1-4 => start day,hr,min,sec
5-8 => end day,hr,min,sec
0's => all.
9 => first ant. no. +
10 => 0=RCP, 1=LCP, 2=both.
FPARM antennas 1-30 factor
RPARM antennas 31-60 factor
VPARM antennas 61-90 factor
DOWEIGHT -1.0 1.0 > 0 => correct weights too
DOCENTER >= 0 -> center frequency axis
Use: Scale visibility amplitudes by antenna based constants.
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.
OUTNAME....Output UV file name (name). Standard defaults.
OUTCLASS...Output UV file name (class). Standard defaults.
OUTSEQ.....Output UV file name (seq. #). 0 => highest unique
OUTDISK....Disk drive # of output UV file.0 => highest w room
1-4 => start day, hour, min, sec
5-8 => end day, hour, min, sec
9 => first antenna number plus 100*(array #-1)
If antenna number = 0, all baselines of the
specified array will be multiplied by
FPARM(1). If < 0, all baselines of all
arrays will be multiplied by FPARM(1).
Use APARM(9)=1 in most cases.
10 => 0=RCP, 1=LCP, 2=BOTH
FPARM......1-30 are antenna factors for antennas 1-30.
RPARM......1-30 are antenna factors for antennas 31-60.
FPARM......1-30 are antenna factors for antennas 61-90.
DOWEIGHT...> 0 => correct weights too (normally a good idea).
DOCENTER...>= 0 => Change frequency axis reference pixel to
Nchan / 2 + 1
else => do not change reference pixel
VBCAL: Task to scale some antenna calibrations by constants.
DOCUMENTOR: R. C. Walker NRAO/CV
RELATED PROGRAMS: VBFIT,UVFLG
VBCAL will multiply the amplitudes in a uv data set by
antenna based calibration constants. Data to be corrected can
be selected by timerange, antenna and array. The program is
primarily intended to be useful in calibrating VLB data, but
can be used to scale any type of data. It can be used to
apply a global, constant scale factor to any data, for
instance, if the flux density calibration of an experiment
is found to be wrong.
The desired timerange is specified with the APARM array.
The first four elements are the start time and the next four
are the stop time, both specified as day,hour,minute,sec.
Times are the IAT as displayed by programs such as LISTER at
the VLA. The first day of the experiment is day 0. For
example, to select all data in the range: day 0, 07:30:15 to
day 1, 12:34:00, specify BPARM=0,7,30,15,1,12,34,00
APARM(9) is used to specify the first antenna to be
processed. If the uv data base contains
data from more than one array, the array number is specified
with the hundreds digit which is set to the array number minus
one. eg: if the first antenna is number 9 of only one array,
use APARM(9)=9. If the first antenna is number 5 of the third
array, use APARM(9)=205. If the antenna number specified is
zero, all antennas of the specified array will be multiplied
by BPARM(1). Note that if APARM(9)=0, all antennas of array
one and only array one will be multiplied. If APARM(9) is
less than zero, all antennas of all arrays are multiplied by
APARM(10) is used to specify the polarization to be
scaled. 0 for RCP, 1 for LCP, and 2 for both. For spectral
line data, all data of the requested polarization will be
BPARM is used to input the scale factors for the 10
antennas beginning with the one specified in APARM.
A value of 0 is replaced by 1.0.
100,000 Visibility records can be processed in about
60 seconds of cpu time. In an empty machine, the program
only seems to be able to use about 50 percent of the available
cpu so the run time will be at least twice the cpu time.