[daip] bad amplitude

[Data Analysts]

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>From chris at nac.oa.uj.edu.pl Mon Sep 23 06:54 MDT 2002
From: Krzysztof Chyzy <chris at oa.uj.edu.pl>
Subject: bad amplitude
To: analysts at cv3.cv.nrao.edu
Date: Mon, 23 Sep 2002 14:54:07 +0200 (CEST)
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Dear Analyst,

I'm not sure if you have got my previous e-mail about some problems with
data reduction so I enclose it again below. I will appreciate
very much if you can help.

Best regards,

Krzysztof
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Forwarded message:
> From chris Sun Sep 15 15:49:16 2002
> Subject: bad amplitude
> To: analysts at nrao.edu
> Date: Sun, 15 Sep 2002 15:49:16 +0200 (CEST)
> X-Mailer: ELM [version 2.5 PL3]
> Content-Length: 2015      
> 
> Dear Analyst,
> 
> In our recent project AU88-01 we observed with the VLA D-config. 
> in C-band a dwarf galaxy IC10. Our study is mainly devoted to detailed
> polarization study of this BCG galaxy so we obtained 3 times
> 8h observing time on: 4 Dec 01, 28 Dec 01, 31 Dec 01 to make
> a sensitive search for regular magnetic fields.
> 
> The data quality from the first two days are acceptable, but I cannot
> properly calibrate the data from 31 Dec to have similar results to 
> the first 2 days. Some numbers to show possible error of the corruption 
> (the data were carefully inspected and flagged):
> 
>                  4 Dec      28 Dec     31 Dec
> 
> getjy task       3.74Jy    3.75Jy    8.18Jy 
> sour 3C138    
> 
> getjy task       1.14Jy    1.13Jy    2.04Jy
> sour 0059+581     
> (phase calibrator)
> 
> task edita       60-70A    60-70K    60-160(or -200)K - all antennas!
> range of Tsys
> 
> tvstat, IC10,    1.2e-5Jy  1.2e-5Jy  3.1e-4Jy
> rms in TP map
> 
> total flux       152mJy    150mJy    221mJy
> IC10                                 less extended
>                                      structure visible
> 
> The SN table (also TY) shows a gradual huge increase of the signal (amplitude) 
> from the beginning (31 Dec 2001 20:29) up to about the middle of the 
> observation (01 Jan 2002 00:30) and then similar decrease to the end of the 
> observing run (01 Jan 2002 04:28). From the observing log I know that it was 
> snowing and for a half of hour the operator was running the SNOW program to
> dump snow from dishes. 
> 
> Could you advise me what to do, please? At this stage the data from the
> third day is useless. What was the cause of this big rise and the fall down
> of the amplitude? The phase signal is O.K. 
> 
> Best regards,
> Krzysztof
> 
> -----------------------------------------------------------------------
> Dr. Krzysztof T. Chyzy                       e-mail: chris at oa.uj.edu.pl
> Astronomical Observatory                          uochyzy at cyf-kr.edu.pl 
> Jagiellonian University
> ul. Orla 171, 30-244 Krakow, Poland
> tel (+48 12) 4121771
> fax (+48 12) 4251318
> 
> 



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