question - DATAMIN

szalaitom wrote on Mar 08, 2011

Hi,

I have a problem with the apphot/phot package. I would like to carry
out aperture photometry on some template-subtracted images. I only
need the flux value within the given aperture radius, without any sky
subtraction (to reduce the possible contamination by imperfectly
subtracted sources lying within the annuli).
There is no possibility to set DANNULUS to zero, therefore I set
SALGORI=constant and SKYVALU=0.
It works, but there is a problem: I would like to filter out pixels
with negative values witihn the aperture, but DATAMIN parameter does
not work with the sky parameters mentioned above.

Is there any way to solve my problem?

Thank You very much for your answer,

sincerely:
Tamas Szalai
(University of Szeged, Hungary)

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Francisco Valdes wrote on Mar 08, 2011

I did not develop the code nor am I very familiar with it. I would have to work my way through the code to see if the datamin limitation is there and how to change it. But it is likely that it is a logical flaw that datamin won't work with the constant sky algorithm.

A suggestion might be to allow a sky to be included but then when you get the output, which I believe includes information about the sky, add back any sky that was subtracted.

Let me know if I should investigate your problem more deeply.

Frank Valdes

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Last post on Mar 08, 2011