mueller_matrix_model.py

from astropy.io import fits
import numpy as np
from vampires_dpp.constants import SUBARU_LOC, PUPIL_OFFSET
import vampires_dpp.mueller_matrices as mm

def mueller_matrix_miles(filename):
    header = fits.getheader(filename)

    bs_ord = header["U_CAMERA"] == 1

    pa_theta = np.deg2rad(header["PA"])
    hwp_theta = np.deg2rad(header["U_HWPANG"])
    alt = np.deg2rad(header["ALTITUDE"])
    az = np.deg2rad(header["AZIMUTH"] - 180)
    lat = SUBARU_LOC.lat.rad # 19.825504°
    hwp_offset = alt + 0.5 * np.arctan2(np.sin(az), np.sin(alt) * np.cos(az) + np.cos(alt) * np.tan(lat))

    imrot_theta = np.deg2rad(header["D_IMRANG"])
    # QWP are oriented with fast-axis vertical on bench, facing the "wrong" way
    qwp1_theta = np.pi/2 - np.deg2rad(header["U_QWP1"])
    qwp2_theta = np.pi/2 - np.deg2rad(header["U_QWP2"])
    flc_theta = 0 if header["U_FLCSTT"] == 1 else np.pi/4

    pupil_offset = np.deg2rad(PUPIL_OFFSET) # 140.4°

    M = np.linalg.multi_dot((
        mm.wollaston(bs_ord),
        mm.hwp(flc_theta),
        mm.rotator(-pupil_offset),
        mm.qwp(qwp2_theta),
        mm.qwp(qwp1_theta),
        mm.hwp(imrot_theta),
        mm.hwp(hwp_theta + hwp_offset),
        mm.rotator(-alt),
        mm.mirror(),
        mm.rotator(pa_theta)
    ))

    return M