Listing Visibilities

1. The task prthd summarizes some basic information about your visibility dataset (it also summarizes images). It only reads the first few records of the data, so if you have multiple frequency setups or sources, it will only report the first setting. It will tell you the number of visibilities, the number of spectral-channels, the number of spectral-windows (IFs), the polarizations present and some information about frequencies. Output can be directed to a log file (the terminal is the default), and either a brief or full listing can be given (the default is the full listing). Several inputs can be given (wildcards are supported).

2. The task uvindex scans through the visibility dataset and reports changes in the source, pointing centre, number of spectral-channels, observing frequency, and polarization. Thus, it builds a description of your observation for general reference. Give the visibility dataset name with the keyword vis. The output can be directed to a text file for printing via the keyword log.

3. The task uvlist can be used to list the values of the correlations. The generic Miriad keyword options is used to control exactly what is listed (see the help file). The standard keywords select and line are used to select the desired visibility data and the desired part of the spectrum, respectively. Here is an example.

   UVLIST
   vis=vela.uv	Specify visibility dataset
   options=data,brief	Lists correlations (this is the default)
   or
   options=spectra,brief	Lists info. about the spectral-windows
   select=pol(xx),ant(1)	List XX correlation for all
   	baselines involving antenna 1
   line=channel,1,128,1,1	List data for channel 128 only
   recnum=100	List 100 records
   log=xx.txt	Write results to this text file or
   	leave unset to write to standard output