Content-type: text/html Manpage of uvredo


Section: User Commands (1)
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uvredo - Recompute various derived quantitues in a uv data-set  




uv analysis  


UVREDO recomputes various derived quantities in a uv data-set. This may be needed if the derived quantities are wrong for some reason, or if there is a need to change a coordinate system. For example uvredo can recompute velocity information, thus allowing conversion between different velocity rest frames.

A patch for handling SMA data has been added into UVREDO in consideration of the fact that the sky frequency given in the archived SMA data has been corrected for a part of the tracked Doppler velocity (the diurnal term and a part of the annual term). The SMA patch calculates the proper residual Doppler velocity for each of the data records corresponding to the "corrected sky frequency".

NOTE: The recomputation relies on a number of parameters in the data-set, such as "time". It is assumed that this information is correct. Uv variables that are important are: For velocity: time and latitu,longitu (or telescop is these are missing).  


The name of the input uv data set. No default.
The normal uv selection commands. The default is to select everything.
The normal uv linetype in the form:
The default is all channels. Note that if there are multiple spectral windows, the fitting process is performed on each window separately.
The polarization/Stokes parameters to be copied to the output data-set. The default is to copy the polarisation/Stokes parameters unchanged.
The name of the output uv data-set. There is no default name.
This gives extra processing options. Several options can be given, each separated by commas. They may be abbreviated to the minimum needed to avoid ambiguity. Possible options are:
   'velocity'    Recompute velocity information.
   'chi'         Recompute parallactic angle information.
The following options can be used to turn off calibration corrections. The default is to apply any calibration present.
   'nocal'       Do not apply the gains table.
   'nopass'      Do not apply bandpass corrections.
   'nopol'       Do not apply polarizatiopn corrections.
   'smaveldop'   Recompute the veldop for SMA data.
                 Keyword: dopsour must be given. 
If options=smaveldop, this gives the source name, on which the Doppler motions were tracked by the SMA online system. dopsour is case-sensitive.
If options=smaveldop, this gives the UT time to calculate the annual term as a reference value. The offset from this reference value in the annual term has been used in the SMA online correction to the Doppler tracked sky frequency in addition to the diurnal term. The keyword doptime is in the format of [dd,hh,mm,ss.s; 4 values]. The default is null. If doptime is null, UVREDO reads the residual Doppler velocity (veldop) of the Doppler tracked source and recomputes the residual Doppler velocity for each of the selected data records. The residual Doppler velocity is then stored into the header variable "veldop" corresponding to the "corrected sky frequency" ("sfreq").
If options=velocity or options=smaveldop, this gives the rest frame of the output data-set. Possible values are 'observatory', 'lsr' and




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Time: 18:35:39 GMT, July 05, 2011