PSF formula discrepancies
Summary
The PSF implemented in the file psf_model.py
has several differences with respect to equation (4) of the paper:
- The cubic term in SR is not written in equation (4)
- The constant term in Sf corresponds to a linear term in the paper
What is the expected correct behavior?
The cubic term is probably just an addition, but the constant or linear term for the phi
scale should be cross-checked.
Furthermore, I would have expected the scale along phi
to be of the form
Sf = sf0 * f(r) / r
with f(r)
a function corresponding to physical differences (optics), sf0
a constant scale factor, and the 1/r
a geometric factor correcting for the physical distance corresponding to a small angle at different distances to the center.
Note: As long as the scale function fits correctly the data points and that the interpolation seems reasonable, one form of function or another would probably have very little impact on the results.
Edited by Gregoire Uhlrich