[daip] frequencies from listr?

[Eric Greisen]

Mark Thompson writes:

 > The two questions I have are that the Source summary table (2) gives the 
 > velocity type as topocentric. This is a little worrying as I was hoping 
 > that the LSR velocity is taken into account somewhere, not the 
 > topocentric velocity. Is this anything to worry about?

       Do not worry I think that there may be a communication between
VLA and FILLM problem.  I will check.

 > 
 > The main problem I am having is with the frequencies in the frequency 
 > table (4). Are they given as sky frequencies? (the same as in imh)
 > 
 > I have a multi-frequency galactic dataset with many sources of different 
 > LSR velocity. I am trying to read them in with FILLM and get everything 
 > to line up properly in frequency. If the frequencies given are sky 
 > frequencies then the LSR correction should be OK as it will come later. 
 > If the frequencies aren't then something has gone very wrong with the 
 > data and the lines probably aren't centred in the band.

What frequencies would they be if not sky?  There are a ton of
frequencies inside the VLA but the only one of interest is the one on
the sky that sets the baseline lengths in wavelengths.  Run POSSM and
see if the lines are where you expect.  If they are strong enough you
may see them without calibration.

Eric Greisen