HiI'm doing time series photometry on a relatively dense open cluster which makes PSF fitting necessary. When computing the psf model and subtracting the model, there are of course still residuals present. In general brighter stars have larger residuals (because of higher flux values -> poisson noise).
The relative errors (measured in an aperture after subtraction) range (in my case) from <<1% (for single, not contaminated field stars) to several tens of % (for contaminated stars) which is of course expected.
By relative errors I mean the magnitudes measured with aperture photometry relative to the magnitudes resulting from the subsequent psf photometry.To deal with these residuals one can calculate an aperture correction.So far I assumed that the relative error does not depend on the magnitude of the star, in other words: I used the same aperture correction for every star in the frame.Is there any way to measure the correction for each star, since the assumption above is certainly not 100% reliable?
I tried to do ordinary aperture photometry on the psf-subtracted frames, which gives the total counts inside an aperture around the residuals. But since psf-fitting with allstar results only in corrected magnitude values (not counts), I can't apply the aperture correction on my own...any help?
thanks
What I want to do is to measure an aperture correction for each star in the frame
New Topic
Post Reply
PSF Photometry Aperture correction
11/26/2010 07:30PM (Read 2148 times)
Quote
