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Flux and bandpass calibration using secondary following block drop

Posted: Fri Jul 07, 2023 6:16 pm
by and476
Hi all,

I had a drop block during one of my observations before I had the chance to observe 1934. I was observing at both 4cm and 15mm so I am using 1934 for both flux and bandpass calibration. It was block 21 so I had to rerun dcal when the block was back online. As a result, the 1934 observations I took near the end of my run wont be good for calibrating those observations before the block drop.

I was wondering if there was a good Miriad recipe for how to use my phase calibrator from the second half of my observations (part 2), which is properly calibrated using 1934 to calibrate the first half of my observations (part 1)? I have done a normal reduction of the observations following the block drop using 1934.

Thanks very much,
Gemma

Re: Flux and bandpass calibration using secondary following block drop

Posted: Mon Jul 10, 2023 4:09 pm
by Mark.Wieringa
I don't have a detailed recipe, but you could try something like the following:
use the second part of the run to create a flux model for the secondary using uvfmeas (options=mfflux) - if it is strong enough to use as a bandpass calibrator for the first half, you can put the model in mfcal's flux parameter. You can similarly specify the flux and spectral index in gpcal.

Re: Flux and bandpass calibration using secondary following block drop

Posted: Tue Jul 11, 2023 10:29 am
by ste616
Hi Gemma,

I should note that unless you did an acal after you recovered from the block drop, and if you kept the tvchannels the same before and after the drop, then you might not need to do anything special.