[daip] [!6921]: AIPS - VLBA continuum data reduction----three questions

[Amy Mioduszewski]

Amy Mioduszewski updated #6921
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       Staff (Owner): Amy Mioduszewski (was: -- Unassigned --)
                 Due: - Cleared - (was: 26 July 2015 09:04 PM)

VLBA continuum data reduction----three questions
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           Ticket ID: 6921
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/6921



Hi Hui,

First the PCOR question.  That error message says that it needs more than one pulse cal tones, nothing to do with the data structure, simply there were not enough PC tones in the PC table.

As for a lot of failed solutions with FRING, you do not send me your inputs so it is hard to say.  Did you only fringe fit on your calibrators?  If you included your target, I would not be surprised if over half the solutions failed.  If it was only the calibrators, I am a little surprised since your phase calibrator looks a little weak, but not horrendously so.  Setting the SNR to 3.5 is not really a good idea.  As for the "strange results" they are simply a result of FRING not finding solutions.  If there are failed solutions in the SN table then CLCAL will flag the associated data, unless you tell it not to.  I am also surprised that changing the DPARM did not change the number of solutions found, it indicates to me that the problem is probably elsewhere.

One thing to try is CALIB instead of FRING.  Because CALIB is not fitting delay and rate it doesn't not need as much signal.  Of course it does not fit delay and rate so the solution probably isn't as good, but it would be a good diagnostic.



Amy Mioduszewski
NRAO

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