DAOPHOT/psf - sampling interval of residuals
ameisner wrote on Oct 04, 2008
I know that when DAOPHOT/psf creates a PSF, the residual table has twice the sampling interval of the actual data used to create the psf. Given that generally a large number of stars are used to create the psf, it seems like it would be reasonable to expect the residual table could be produced with an even higher sampling rate. However, I can't figure out any way to specify the sampling rate for the residuals. Is this possible, and if so how can it be done? Thanks.
Francisco Valdes wrote on Oct 04, 2008
Hello,
The author of the IRAF DAOPhot version has left the IRAF group. I don't know if the choice of the sampling factor has a specific reason (including being a direct port of the original DAO code). I looked at the code and it appears the size is hard-coded and there is definitely no user parameter to change it.
You could use a general image task to "magnify" the psf image, though that would not be exactly the same as computing residuals from the analytic fit. It might also not work when this is then used in subsequent DAOPhot tasks.
Sorry this option is not available.
Yours,
Frank Valdes
The author of the IRAF DAOPhot version has left the IRAF group. I don't know if the choice of the sampling factor has a specific reason (including being a direct port of the original DAO code). I looked at the code and it appears the size is hard-coded and there is definitely no user parameter to change it.
You could use a general image task to "magnify" the psf image, though that would not be exactly the same as computing residuals from the analytic fit. It might also not work when this is then used in subsequent DAOPhot tasks.
Sorry this option is not available.
Yours,
Frank Valdes
Last post on Oct 04, 2008