How to correctly read in visibility data from a FITS file using IDL

1ytrewq

Hi,
I'm having some trouble reading in some data from a FITS file. The FITS file has visibility data for 256 different frequency channels but I only seem to be able to read in the data for the first frequency channel. My question is how do I change which frequency channel I want to look at, for example look at the 100th freq channel rather than the first?

The code I have written in IDL to open the file and extract information so far is:


infile = 'finaluv.fits'

data = mrdfits(infile,0,hdr)

params = data.params
array = data.array

u = params[0,*]
v = params[1,*]
baseline = params[5,*]

real = reform(array[0,0,100,*])
imag = reform(array[0,0,100,*])

visibility = sqrt(real^2+imag^2)
uvdistance = sqrt(u^2 +v^2)