Monday, May 21, 2007

UVRANGEs contradict Calibrator Quality Ratings

What does it mean if your calibrator has a good ("P") rating in the calibrator manual for your array configuration whose longest baseline is ~50 kilolambda--- but then there's a uvrange limitation on it with a uvmin of 100 kilolambda? I'm trying to use calibrator 0841+708 at C band in C array.

Resolution: After talking to Miller Goss, I think that this must be a typo in the manual. The amplitudes look fine, for the most part, and there is no obvious confusing source in the field. So, I guess this is just a word of caution about the manual, that it can make mistakes some times!

More Resolution: Rick Perley had this to say about the current state of the VLA calibrator manual:

  Right you are!  The 'P' in that column/row should be an 'S', I think.  It's one of the 'core-dominated' source
types that make good high frequency, high resolution calibrators.
Nobody is keeping up the manual these days (Greg Taylor used to do this, but he's now gone to UNM). We'll
certainly get back on this after the EVLA settles in, and we'll be able to utilize far more sources as calibrators.
In the meantime, I'll make a note in my copy.

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