PSF defined in pixel space #283
Description
Is your refactor request related to a problem? Please describe.
The PSF is a property of the dector and so its natural alignment is against the pixel grid, not the sky. Two images at different alignments will have diffraction spikes that are aligned with the grid not the sky. Thus a PSF model ought to be aligned with the pixel grid.
Describe the solution you'd like Separate the PSF image object from the base image object so that its coordinate system can be appropriately defined.
Describe alternatives you've considered Its possible to use caskade param functional relations to fix this, but that is overly cumbersome