task for photometry on extended features?
Arp wrote on Oct 29, 2009
Hi!
Since I'm still relatively new to iraf, I've got a question yet again :)
I want to do photometry on sdss images. I managed to use imexam to show me the magnitudes of stars, and it corresponds well to values given on the sdss page. Now I want to get a magnitude for extend objects, or at least Objects which are not stars, like a background region. I thought, since imexamine knows the fluxlevels in the image, I could just put an elliptical region somewhere, and just get the total flux in this region, and then calculate the magnitude. with which task can this be done? I've read about phot, and daophot and so on, but they all seem to work on (or even need) stars...
Which package/task can I use for non star photometry?
thanks.
Since I'm still relatively new to iraf, I've got a question yet again :)
I want to do photometry on sdss images. I managed to use imexam to show me the magnitudes of stars, and it corresponds well to values given on the sdss page. Now I want to get a magnitude for extend objects, or at least Objects which are not stars, like a background region. I thought, since imexamine knows the fluxlevels in the image, I could just put an elliptical region somewhere, and just get the total flux in this region, and then calculate the magnitude. with which task can this be done? I've read about phot, and daophot and so on, but they all seem to work on (or even need) stars...
Which package/task can I use for non star photometry?
thanks.
Arp wrote on Oct 29, 2009
Hi!
I got a similar question too...
As I said, imexamine shows very accurate magnitudes, compared to the SDSS magnitudes, but when I make a polygon around the same star, and use polyphot, the magnitude is about 5 mags lower... do you have any Idea what the problem could be?
I got a similar question too...
As I said, imexamine shows very accurate magnitudes, compared to the SDSS magnitudes, but when I make a polygon around the same star, and use polyphot, the magnitude is about 5 mags lower... do you have any Idea what the problem could be?
Last post on Oct 29, 2009