psf from other field of view
Robert Janusz wrote on Jan 09, 2009
I have two frames of fields of view A and B (shifted). I do aperture photometry and then PSF-photometry: selecting candidates, etc. allstars-task on the A. Can I somehow use the psf-model for the B field of view without selecting candidates etc., just use the data learned with A?
Robert
Robert
Philip Massey wrote on Jan 09, 2009
No, one should not use the identical psf. One would expect there to be slight differences due to slight differences in the guiding and seeing.
However, it is straightforward to then choose the same psf stars. When you
run psf on frame A, there will be an output file containing the IDs and x's and y's of the pst stars. You then need to identify those stars in frame B's aperture
photometry file, and feed those IDs in when making the psf for frame B.
Do a help psf, and take a look at my "Stellar Photometry with IRAF" guide
in the documentation section for guidance.
However, it is straightforward to then choose the same psf stars. When you
run psf on frame A, there will be an output file containing the IDs and x's and y's of the pst stars. You then need to identify those stars in frame B's aperture
photometry file, and feed those IDs in when making the psf for frame B.
Do a help psf, and take a look at my "Stellar Photometry with IRAF" guide
in the documentation section for guidance.
Last post on Jan 09, 2009