[daip] Convolving from Jy/px to Jy/beam

[Amy Mioduszewski]

Dear Juan-Carlos,

Sorry! I misinterpreted the HELP file.  I am looking at the code now.  It says 
if (jy/pix and GAUS and FACTOR<=0) then 
FACTOR=1.1331*(BMAJ(deg)/xinc)*(BMIN(deg)/yinc), where xinc and yinc are the 
axis increment.  So we are back to where you started yesterday.  Could you do an 
IMH and send me the headers of the pre and post convolved images?

Thanks,

Amy

Juan-Carlos Algaba-Marcos wrote:
> Dear Amy,
> 
> Thank you for your quick answer.
> The convolving beam I am used is about 10x10 pixels, which, naively thinking, would
> agree with the factor of 100 in the convolved flux when I use FACTOR=0, assuming the
> typo in the output units. However, if I use FACTOR=1 the output flux is very similar to
> the un-convolved theoretical image and is still showing units of Jy/pixel.
> 
> Thank you very much
> 
>        J. C. Algaba
> 
> 
> ---------- Original Message -----------
> From:Amy Mioduszewski <amiodusz at nrao.edu>
> To:Juan-Carlos Algaba-Marcos <algaba at asiaa.sinica.edu.tw>
> Cc:daip at nrao.edu
> Sent:Wed, 11 Apr 2012 13:37:31 -0600
> Subject:Re: [daip] Convolving from Jy/px to Jy/beam
> 
>> Hi Juan-Carlos,
>>
>> The help file is a bit confusing, it looks like if OPCODE='GAUS' and the input 
>> image is in Jy/pixel then FACTOR=1 will convert the units to Jy/beam.  If 
>> FACTOR=0 then it will be unscaled.  Is you convolving beam several times your 
>> pixel size?
>>
>> Amy
>>
>> Juan-Carlos Algaba-Marcos wrote:
>>> To whom it may concern,
>>>
>>> We have a theoretical image in Jy/pixel that we want to convolve with a beam to obtain
>>> an image with the units of Jy/beam. To do so, we are using the task CONVL. Inputs are
>>> INNAME, etc= theoretical image
>>> OPCODE='GAUS'
>>> BMAJ,BMIN=desired convolving beam
>>> FACTOR=0
>>> However, although the image seems to be properly convolved, the units of the output
>>> image are still in Jy/pixel. From the values we get (~3e-4Jy/pixel before convolving and
>>> ~3e-2Jy/pixel after convolving) we think this is just a bug, with text not being updated
>>> to show the proper units. However, we would like to double-check this to make sure the
>>> convolution is indeed as expected, and change in flux s not due to other effects. Could
>>> you please advise us in this topic?
>>>
>>> Thank you very much,
>>>
>>>        J. C. Algaba
>>>
>>> _______________________________________________
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>>> Daip at listmgr.cv.nrao.edu
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>>>
> ------- End of Original Message -------
>