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import galsim
import sep
import numpy as np
from scipy.interpolate import interp1d
import pylab as pl
import os, sys
class PSFModel(object):
def __init__(self, sigSpin=0., psfRa=0.15):
# TODO: what are the nesseary fields in PSFModel class?
pass
def PSFspin(self, psf, sigSpin, sigGauss, dx, dy):
"""
The PSF profile at a given image position relative to the axis center
Parameters:
theta : spin angles in a given exposure in unit of [arcsecond]
dx, dy: relative position to the axis center in unit of [pixels]
Return:
Spinned PSF: g1, g2 and axis ratio 'a/b'
"""
a2Rad = np.pi/(60.0*60.0*180.0)
ff = sigGauss * 0.107 * (1000.0/10.0) # in unit of [pixels]
rc = np.sqrt(dx*dx + dy*dy)
cpix = rc*(sigSpin*a2Rad)
beta = (np.arctan2(dy,dx) + np.pi/2)
ell = cpix**2/(2.0*ff**2+cpix**2)
#ell *= 10.0
qr = np.sqrt((1.0+ell)/(1.0-ell))
#psfShape = galsim.Shear(e=ell, beta=beta)
#g1, g2 = psfShape.g1, psfShape.g2
#qr = np.sqrt((1.0+ell)/(1.0-ell))
#return ell, beta, qr
PSFshear = galsim.Shear(e=ell, beta=beta*galsim.radians)
return psf.shear(PSFshear), PSFshear