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Basic Information on xyphase
Task: xyphase
Purpose: Determine XY phase corrections from on-line measurements.
Categories: uv analysis
XYPHASE is a MIRIAD task, which determines XY phase corrections
from the on-line XY phase measurements. This can calculate
an antenna gain and/or a bandpass function.
This cannot cope with multi-IF data-sets. Bad solutions will result
if you attempt to use it for this data.
The input data should contain either the "xyphase" uv variable
(the on-line XY phase measurement), and/or autocorrelation data. The
autocorrelation data is required if the bandpass is being solved for.
Note that the "xyphase" variable is lost if the data enters Miriad
via FITS (unless ATMERGE is used). The autocorrelation data is
currently not written when using the standard correlator
configurations.
Key: vis
The input visibility data-set. No default. This should contain
raw ATCA polarisation data (i.e. XX,YY,XY,YX correlations).
Key: select
Normal uv selection criteria. The default is to select all data.
Polarisation selection should not be used.
Key: refant
The reference antenna. By default XYPHASE computes the gains and
bandpasses for all antennae. By specifying a reference antenna,
XYPHASE finds solutions for only the reference antenna, and sets the
other phases to zero. This is as other programs (such as GPCAL and
MFCAL) can determine all but the reference antennas XY phases.
Key: interval
This gives one or two numbers, both given in minutes, both being used
to determine the interval over which the antenna XY phase is assumed
to remain constant. The first number gives the maximum length of
a solution interval. The second number gives the maximum gap size in
a solution interval. A new solution is started when either the
maximum time length is exceeded, or a gap larger than the max gap is
encountered. The default is a maximum length of 5 minutes, and a
gap size which is the same as the maximum length.
Key: break
The times, in the normal Miriad format, where to insert the
break point. A ``break point'' gives a time where some form of
instrumental glitch took place, and the xyphases jumped. By
giving a break point, you prevent a solution interval from spanning
this time, and you inhibit gain interpolation across the time.
Key: options
Extra processing options. Several options can be given, separated
by commas. Minimum match is used.
noxy Do not determine the antenna XY phases. By default
XYPHASE will solve for this when the "xyphase" variable
is present in the data.
nopass Do not determine the XY bandpass function. By default
XYPHASE will solve for this when autocorrelations are
present in the data.