make an empirical psf in IRAF/DAOPHOT?

ameisner wrote on Jul 15, 2008

I know that the DAOPHOT psf function is intended to make a psf consisting of an analytic fit + one or more look up tables...however, for my purposes the fitting functions I've tried (gauss,moffat) give a psf that is too sharply spiked in the center and result in problems (severe over/undersubtraction) in the central regions of objects from which the psf model has been subtracted. I was wondering if there is any way to create an entirely empirical psf with DAOPHOT psf or to make one elsewhere and import it for use with DAOPHOT nstar/substar...I'm pretty certain the fitting is causing the problem I see because even when I create a psf based on a single star and subtract that star's psf from itself, I see noise in the very center indicating an inability to fit the central region. I looked in daopars but couldn't find a way to turn off the analytic component of the psf model. Thank you very much for any help.

ameisner@stanford.edu

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Last post on Jul 15, 2008