The psfex option is BASIS_TYPE which we want to allow to be PIXEL or PIXEL_AUTO.

Thanks for reviewing Paul.

Is it intentional that the new option has no default? Without a default, it needs a coordinated change in obs_subaru (and any other obs package that uses psfex) to set a value.

I would have expected that it would have been a boolean option (e.g., allowOversampling) that then gets interpreted when setting the BASIS_TYPE parameter, but maybe what you've done makes more sense for those familiar with psfex.

Is the FWHM = 3 pixels divide hardcoded in psfex?

Ah, no. It should have a default. Thanks for catching that.

I don't really want people to use the non-default option as the oversampling should be controlled from the other config parameters, unless they know what they are doing. We do want to use this option for hsc so we need to update obs_subaru. Should it be on the same ticket?

Yes, the FWHM=3 is hardcoded into psfex.

Please update obs_subaru here. Otherwise we have to make another ticket, which is more work.

Looks good.