Each pixel in a plot corresponds to a single pointing of a 225-beam observation.
The x and y axes are in degrees, and represent offsets from the central pixel
which is at the coordinates of CygA. The range in each plot is set to scale
between 0 and the maximum gain for that station. White pixels correspond to
pointings which did not record data to disk (usually due to cluster problems).
The four subplots correspond to the four (complex) elements of the Jones matrix
that we assume describes the beam response. Only the amplitude is plotted.