iraf.net

Hi,What is the matching radius in PSF if the parameter matchbyid=no? I would guess it is "matchrad" in "daopars", but this does not seems to be documented anywhere. Could you please confirm? Thanks.Vallery

From the help page:[quote:f5200e2371]
If 'matchbyid' is "no" or there is no input psf star list "PSFMAG" is
set to the magnitude of the first PSF star in the input photometry file.
[/quote:f5200e2371]So it appears to be always just the first value, no matching at all. The code seems to bear this out.

[quote:9d8182ee7e="fitz"]From the help page:[quote:9d8182ee7e]
If 'matchbyid' is "no" or there is no input psf star list "PSFMAG" is
set to the magnitude of the first PSF star in the input photometry file.
[/quote:9d8182ee7e]So it appears to be always just the first value, no matching at all. The code seems to bear this out.[/quote:9d8182ee7e]My question was not about the magnitude of the PSF, but rather how the stars in the photometry and the PSF star files are matched if "matchbyid=no". If it is set to "yes" it is clear: the stars are matched by ID. If it is "no", I guess the stars are matched by their (x,y) positions with some tolerance. The question was if the tolerance is "matchred" in daopars. The help says "matchrad" is used when PSF stars are selected interactively.

Sorry, misunderstood. It actually appears to be "2 * matchrad" as the critical radius. The code in question is daophot$psf/dplocstar.x

[quote:cd2a4c79a3="fitz"]Sorry, misunderstood. It actually appears to be "2 * matchrad" as the critical radius. The code in question is daophot$psf/dplocstar.x[/quote:cd2a4c79a3]thanks