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<p>Dear Eric Greisen,</p>
<p><br>
</p>
<p>Thank you very much for you suggestion.</p>
<p><br>
</p>
<p>Yours sincerely,</p>
<p>Jedsada Maklai</p>
<p><i><span style="color:rgb(0,111,201)">Research Assistant (by Dr. Ram Kesh Yadav)</span></i></p>
<p><i><span style="color:rgb(0,111,201)">National Astronomical Research Institute of Thailand (NARIT)</span></i><br>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Eric Greisen <egreisen@nrao.edu><br>
<b>Sent:</b> Tuesday, July 25, 2023 10:10:01 PM<br>
<b>To:</b> Jedsada Maklai<br>
<b>Cc:</b> daip@nrao.edu<br>
<b>Subject:</b> Re: [daip] Question about using AIPS for radio image synthesis {External} {External} {External}</font>
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<div class="PlainText">Step 6 suggests that you run FRING on a single scan and apply that to all<br>
the data. Take the stronger cal source and 1 scan.<br>
<br>
Steps 7 and 8 allow you to do the SETJY and BPASS with both sources. Two<br>
primary calibrators should work as well as having multiple scans on one.<br>
<br>
<br>
> Dear Eric Greisen,<br>
><br>
><br>
> Thank you very much for your previous suggestions again. I would like to<br>
> ask another question.<br>
><br>
><br>
> As per your suggestions, I am following chap. 4 of the AIPS cookbook for<br>
> the calibration. In the section 4.3 (Beginning the calibration), the steps<br>
> 6-8 seem to be applied for only one primary flux calibrator. However, my<br>
> data consists of 2 primary flux calibrators observed at the beginning and<br>
> at the end of the observations. My question is, how should I include both<br>
> the calibrators as per the cookbook's instructions especially in that<br>
> specific part?<br>
><br>
><br>
> Thank you very much in advance.<br>
><br>
><br>
> Yours sincerely,<br>
><br>
> Jedsada Maklai<br>
><br>
> ________________________________<br>
> From: Jedsada Maklai<br>
> Sent: Wednesday, July 19, 2023 3:43:58 PM<br>
> To: egreisen@nrao.edu<br>
> Subject: Re: [daip] Question about using AIPS for radio image synthesis<br>
> {External} {External}<br>
><br>
><br>
> Dear Eric Greisen,<br>
><br>
><br>
> In fact, I have studied the AIPS cookbook for a while. However, I don't<br>
> have any idea of how to calibrate GMRT data.<br>
><br>
><br>
> So, for GMRT data reduction. Is it alright to use the methods suggested<br>
> for VLBI data calibration (at section 9.1 of the cookbook)?<br>
><br>
><br>
> I have already loaded the data using FITLD and INDXR. After that, I<br>
> examine the data with several task suggested in step 2 in that section (in<br>
> which I think that the data looks alright in my sense, which I don't know<br>
> is my sense coherent with AIPS specialists or not)<br>
><br>
><br>
> For step 3, I found problem because GMRT didn't provide any calibration<br>
> file. So I skip this step. I quite not sure is it alright or not.<br>
><br>
><br>
> For step 6 (edit the data), the things that I have to flag is RFI, right?<br>
> Now I quite confuse. I don't know which task is suitable for flagging RFI.<br>
> My idea is using task POSSM to plot cross-correlation of every antenna<br>
> pair in both RR and LL polarization and then note down the channels which<br>
> possibly be RFI in each antenna pair and polarization and then using task<br>
> UVFLG to flag them. The problem is, there are ~30 antennae, 2 pols, 2048<br>
> channels which quite a lot. So could you mind suggest me the effective<br>
> method for flagging RFI?<br>
><br>
><br>
> Could you mind suggest me, please? Sorry, it's quite a bit long.<br>
><br>
><br>
> Yours sincerely,<br>
><br>
> Jedsada Maklai<br>
><br>
> Research Assistant (by Dr. Ram Kesh Yadav)<br>
> National Astronomical Research Institute of Thailand (NARIT)<br>
><br>
><br>
> ________________________________<br>
> From: Jedsada Maklai<br>
> Sent: Wednesday, July 19, 2023 8:54:37 AM<br>
> To: egreisen@nrao.edu<br>
> Subject: Re: [daip] Question about using AIPS for radio image synthesis<br>
> {External} {External}<br>
><br>
><br>
> Dear Eric Greisen,<br>
><br>
><br>
> Thank you very much for your suggestion.<br>
><br>
><br>
> Yours sincerely,<br>
><br>
> Jedsada Maklai<br>
><br>
> Research Assistant (by Dr. Ram Kesh Yadav)<br>
><br>
> National Astronomical Research Institute of Thailand (NARIT)<br>
><br>
> ________________________________<br>
> From: Eric Greisen <egreisen@nrao.edu><br>
> Sent: Tuesday, July 18, 2023 10:09:48 PM<br>
> To: Jedsada Maklai<br>
> Subject: Re: [daip] Question about using AIPS for radio image synthesis<br>
> {External} {External}<br>
><br>
> Let me recommend the AIPS CookBook which is available in your installation<br>
> at $AIPS_ROOT/TEXT/PUBL in chapters named COOK?.PS where ? =<br>
> 1,2,3,...13,A,B,C... or as COOKBOOK.PDF. The Workshop you mention will<br>
> concentrate on CASA rather than AIPS.<br>
><br>
> Eric Greisen<br>
><br>
>> Dear Eric Greisen,<br>
>><br>
>><br>
>> Thank you very much for your suggestion. Using AIPS software is really<br>
>> challenge for me. I never have any chance to have in-person training or<br>
>> workshop before, and the best thing I can do is consulting with some<br>
>> specialists remotely. If I have more chance to continue my job in this<br>
>> area, I will try to attend to NRAO data reduction workshop which will be<br>
>> held next year so my skill in this software will be improved.<br>
>><br>
>><br>
>> Yours sincerely,<br>
>><br>
>> Jedsada Maklai<br>
>><br>
>> Research Assistant (by Dr. Ram Kaesh Yadav)<br>
>><br>
>> National Astronomical Research Institute of Thailand (NARIT)<br>
>><br>
>> ________________________________<br>
>> From: Eric Greisen <egreisen@nrao.edu><br>
>> Sent: Monday, July 17, 2023 10:58:11 PM<br>
>> To: Jedsada Maklai<br>
>> Cc: daip@nrao.edu; Ram Kesh Yadav<br>
>> Subject: Re: [daip] Question about using AIPS for radio image synthesis<br>
>> {External}<br>
>><br>
>> CLINT is the interval between values in the CL table. If the<br>
>> calibration<br>
>> varies rapidly with time, then it should be shorter than 1 minute. At<br>
>> your<br>
>> frequency, the default or 1.05 should be fine. The reason to use QUACK<br>
>> is<br>
>> that on some systems the first first data record or two or three are<br>
>> affected by scan startup issues and have incorrect amplitude or phase<br>
>> compared to the rest. Do not use QUACK until you have examined<br>
>> calibrator<br>
>> source data in detail to see if there are issues at the start and end of<br>
>> scans. That examination will show you what values to use for QUACK if<br>
>> any.<br>
>><br>
>> Eric Greisen<br>
>><br>
>><br>
>>> Dear NRAO staffs,<br>
>>><br>
>>><br>
>>> Now I am doing task QUACK. However, I don't know what the values of<br>
>>> APARM<br>
>>> in it should be. I will do the cutting at the beginning of each scan,<br>
>>> is<br>
>>> it enough? Or should I do the cutting at the end of each scan also? The<br>
>>> attached file shows the scan data which I retrieve from task LISTR.<br>
>>><br>
>>><br>
>>> Could you mind explain how to do the decision about it also, please?<br>
>>><br>
>>><br>
>>> Yours sincerely,<br>
>>><br>
>>> Jedsada Maklai<br>
>>><br>
>>> Research Assistant (by Dr. Ram Kesh Yadav)<br>
>>><br>
>>> National Astronomical Research Institute of Thailand (NARIT)<br>
>>><br>
>>><br>
>>> ________________________________<br>
>>> From: Jedsada Maklai<br>
>>> Sent: Monday, July 17, 2023 10:20:01 AM<br>
>>> To: daip@nrao.edu<br>
>>> Cc: Ram Kesh Yadav<br>
>>> Subject: Question about using AIPS for radio image synthesis<br>
>>><br>
>>><br>
>>> Dear NRAO staffs,<br>
>>><br>
>>><br>
>>> I'm using AIPS in order to do the image synthesis. It is radio<br>
>>> continuum<br>
>>> data from GMRT observation at 1260 MHz.<br>
>>><br>
>>><br>
>>> The question is, in task FITLD, what is the suitable value for CLINT<br>
>>> parameter? and why? What is the criteria for justifying the suitable<br>
>>> value<br>
>>> of CLINT in general?<br>
>>><br>
>>><br>
>>> (Someone used to suggest me that the suitable value should be 1.05 but<br>
>>> I<br>
>>> don't know the reason. My professor said I should know the reason<br>
>>> behind<br>
>>> this also so I will be able to apply it to other observations in the<br>
>>> future.)<br>
>>><br>
>>><br>
>>> So, could you mind explain it to me, please?<br>
>>><br>
>>><br>
>>> Yours sincerely,<br>
>>><br>
>>> Jedsada Maklai<br>
>>><br>
>>> Research Assistant (by Dr. Ram Kesh Yadav)<br>
>>><br>
>>> National Astronomical Research Institute of Thailand (NARIT)<br>
>>> _______________________________________________<br>
>>> Daip mailing list<br>
>>> Daip@listmgr.nrao.edu<br>
>>> <a href="https://listmgr.nrao.edu/mailman/listinfo/daip">https://listmgr.nrao.edu/mailman/listinfo/daip</a><br>
>>><br>
>><br>
>><br>
>> Eric W Greisen<br>
>><br>
>><br>
>><br>
><br>
><br>
> Eric W Greisen<br>
><br>
><br>
><br>
<br>
<br>
Eric W Greisen<br>
<br>
<br>
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