[daip] questions regarding prtan and imagr

Tue May 13 16:42:06 EDT 2008

Hello Leonia, 

  Thank you for your response to my questions.  I have further questions.

> Q1
> 
>> When I inspect the data using the task "UVPLT"
>> for example, it looks like it contains all data of all baselines.
> 
> Yes the data include probably all baselines.
> UVPLT plots the UV data and does not use AN table at all.
> I think your AN table is actually corrupted. I do not know MIR(IDL).
> So I do not know why the AN table is wrong.
> 
> Generally speaking AN table is used at the calibration (at AIPS). So if you
> used 
> the AN table at MIR(IDL) your calibration could miss the 2 antennas depending
> on your
> input parameters.
> 

It's good to know that UVPLT does not use the antenna table.  If I do PRTAN,
the output for the 8 antennas looks reasonable, like

.............................................
Array reference position in meters (Earth centered)
Array BX=  -5462428.40757    BY=  -2491960.45618    BZ=   2286526.65343
Polar X =   0.00000 Polar Y =   0.00000 arcsec
Earth rotation rate =  360.9856449756 degrees / IAT day
GST at UT=0 =  202.5367277361 degrees
UT1-UTC=      0.0000000   Data time(UTC     )-UTC=      0.0000000 seconds
Solutions not yet determined for a particular FREQID
Mount=ALAZ  Axis offset=  0.0000 meters    IFA               IFB
Feed polarization type =                    R                 L

Ant   1 = AN01     BX=        0.0000 BY=        0.0000 BZ=        0.0000
Ant   2 = AN02     BX=       90.4130 BY=     -276.1790 BZ=     -263.6168
Ant   3 = AN03     BX=       85.4508 BY=        1.9548 BZ=     -209.1038
Ant   4 = AN04     BX=       37.0243 BY=     -405.5341 BZ=     -149.5777
Ant   5 = AN05     BX=      154.5661 BY=      -60.0895 BZ=     -399.4778
Ant   6 = AN06     BX=      128.0491 BY=       73.5067 BZ=     -295.3008
Ant   7 = AN07     BX=      139.7886 BY=       19.8421 BZ=     -336.0244
Ant   8 = AN08     BX=       -3.2893 BY=     -178.0796 BZ=       14.1085
.............................................

So, I guess the antenna table is fine except for the fact that the other two
antenna's information is not included.  Do you agree on that?

If the antenna table is used only for the calibration process, would we
expect that the final map after processing IMAGR should be correct as long
as we process the calibration elsewhere?

>> Q2.  When I tried to process the above image with IMAGR, I found
>> I was able to make sensible image only when I use UVWTFN = ' '
>> (uniform weighting).  Does this indicate that something may be
>> wrong for the table that contains weighting information of each antenna?
> In AIPS AN table is created by the task FITLD
> 
> Q2
> 
> IMAGR does not use AN table at all
>

I understand IMAGR does not use the antenna table now.  From where does AIPS
get information required for UVWTFN?

Hope to hear from you.  Thanks very much.

Hiroko

On 08.5.13 10:07 AM, "Leonia Kogan" <lkogan at nrao.edu> wrote:

> Hiroko,
> 
> The main person of AIPS Eric is not at the office now. So I'll try to
> answer you something.
> 
> Q1
> 
>> When I inspect the data using the task "UVPLT"
>> for example, it looks like it contains all data of all baselines.
> 
> Yes the data include probably all baselines.
> UVPLT plots the UV data and does not use AN table at all.
> I think your AN table is actually corrupted. I do not know MIR(IDL).
> So I do not know why the AN table is wrong.
> 
> Generally speaking AN table is used at the calibration (at AIPS). So if you
> used 
> the AN table at MIR(IDL) your calibration could miss the 2 antennas depending
> on your
> input parameters.
> 
> In AIPS AN table is created by the task FITLD
> 
> Q2
> 
> IMAGR does not use AN table at all
> 
> So all your problems are at the beginning: outside of AIPS !!!
> 
> Leonid Kogan
> 
> 
> Hiroko Shinnaga wrote:
>> Dear AIPS experts,
>> 
>>    I'm Hiroko Shinnaga, a staff scientist at the Caltech Submillimeter
>> Observatory.  I have two general questions regarding tasks of PRTAN
>> and IMAGR.
>> 
>> Q1.   I'm dealing with some interferometric data that contains
>> 10 antennas in total.  I first create FITS file using a calibration tool
>> called MIR (IDL base) and generated a FITS file.  Then I read the
>> FITS file to AIPS.  When I inspect the data using the task "UVPLT"
>> for example, it looks like it contains all data of all baselines.
>> However,
>> when I use the "PRTAN", I see only information of 8 antennas.  From
>> the output of "PRTAN", it seems the antenna table seemed to not be
>> transfered properly.  Could you let me know what kind of effect I
>> should expect if I don't have a correct antenna table?
>> 
>> Q2.  When I tried to process the above image with IMAGR, I found
>> I was able to make sensible image only when I use UVWTFN = ' '
>> (uniform weighting).  Does this indicate that something may be
>> wrong for the table that contains weighting information of each antenna?
>> 
>>    Hope to hear from you.  Thanks very much.
>> 
>> Hiroko
>> 
>> 
>> _______________________________________________
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>>   
> 

-- 
Hiroko Shinnaga                     shinnaga @ submm.caltech.edu
Staff Scientist                     California Institute of Technology
Caltech Submillimeter Observatory   Phone: +1-808-935-1909
111 Nowelo Street                   Fax:   +1-808-961-6273
Hilo, Hawai'i 96720 U.S.A.          http://www.submm.caltech.edu/