[daip] [!17215]: AIPS - Regarding OBIT and AIPS: BDFLIST and BDF2AIPS

[Juhi Tiwari]

Regarding OBIT and AIPS: BDFLIST and BDF2AIPS
---------------------------------------------

           Ticket ID: 17215
                 URL: https://help.nrao.edu/staff/index.php?/Tickets/Ticket/View/17215
                Name: Juhi Tiwari
       Email address: j_aquarian_t at yahoo.co.in
             Creator: User
          Department: AIPS Data Reduction
       Staff (Owner): Eric Greisen
                Type: Issue
              Status: Open
            Priority: Default
                 SLA: NRAO E2E
      Template group: Default
             Created: 26 October 2020 03:42 PM
             Updated: 24 November 2020 03:54 PM
           Reply due: 26 November 2020 03:54 PM (2d 0h 0m)
      Resolution due: 13 August 2023 12:00 AM (991d 8h 6m)

 Thanks to your help, I have been able to generate good images of the sources (please take a look at the attached files).
1.Regarding my previous email.. Although things look good you say, I would still like to know how low is low for an amplitude value to be declared as bad or an approximate permissible range of amplitude values to be accepted when using LIST or MATX options in LISTR (assuming we have a single source in the field unlike the scan I am looking at) ?
2. The image radiosources.PS shows the grey scale brightness range = -2.1 to 157 mJy/beam. Can we manually reduce this range while plotting, say to enhance certain portions of the image? Also, if I use an observation with a longer exposure time, will this range change (maybe not so much since I think this should reflect the property of the source)? 
3. 1233+168.PS and 1233+169.PS are sub-images generated from the main source image by setting appropriate values for BLC and TRC. Hence, both of these show the peak surface brightness (SB) and labels corresponding to the original .ICL image. Is there a way to make the peak SB listed in the sub-images correspond to the actual peak SB value there? I could not find a way to do this right at the beginning with the task 'IMAGR' (perhaps I should try a smaller image size), before I enter the tasks 'KNTR' and 'LWPLA'. 
4. I wish to overlay these radio contours on the existing optical and X-ray FITS images I have. Is there a way I can export the radio image outside of AIPS in FITS format?.. and the radio contours?.. and then use software like DS9 for further analysis. I explored a little.. I guess the task KNTR can do overlays. In that case, can FITLD successfully read these optical/X-ray FITS images?
5. How does one choose a good cell size for the image?
6. AIPS sometimes throws the following error: TV DEVICE CURRENTLY BEING USED BY SOMEONE ELSE. Normally, I close everything and restart AIPS and then the error disappears. Any suggestion regarding this?
Juhi 

    On Saturday, 21 November, 2020, 03:05:18 am IST, Eric Greisen  wrote:  
 
 
1. Everything you sent looks good.  I would not worry much about the rms.

2. The scalar vs vector is a good test.  L band phases tend to be stable as you found.

3. Everyone uses 2pt  stay with it for L band.

4. The gain calibrator is a good phase calibrator (or it would not be a good gain calibrator) 

5. The rms is just a measure of the deviation from the mean

6. The calibrator image looks correct.  Your source has a 2nd source within the beam.  The amplitudes and phases will reflect both your source's structure and that of the 2nd source.  So amplitudes and phases will be a function of the location in the uv plane (calibration sources should not have this problem).  Go ahead and make an image - but image a large area so as to get both sources.  The LIST option actually looks pretty good.

You are worrying too much - things look good.

Eric Greisen



Ticket Details
Ticket ID: 17215
Department: AIPS Data Reduction
Type: Issue
Status: Open
Priority: Default

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