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csst_mci_sim/straylight.py

+
+import numpy as np
+import julian
+from datetime import datetime
+from astropy.time import Time
+from astropy.coordinates import get_sun
+from astropy.coordinates import SkyCoord
+import astropy.coordinates as coord
+import pandas as pd
+from astropy import units as u
+
+from scipy.interpolate import interp1d
+
+from scipy import interpolate
+
+import ctypes
+
+
+def transRaDec2D(ra, dec):
+    # radec转为竞天程序里的ob, 赤道坐标系下的笛卡尔三维坐标xyz.
+    x1 = np.cos(dec / 57.2957795) * np.cos(ra / 57.2957795)
+    y1 = np.cos(dec / 57.2957795) * np.sin(ra / 57.2957795)
+    z1 = np.sin(dec / 57.2957795)
+    return np.array([x1, y1, z1])
+
+
+# def earth_angle(time_jd, x_sat, y_sat, z_sat, ra_obj, dec_obj):
+
+#     ra_sat = np.arctan2(y_sat, x_sat) / np.pi * 180
+#     dec_sat = np.arctan2(z_sat, np.sqrt(x_sat**2+y_sat**2)) / np.pi * 180
+#     radec_sat = SkyCoord(ra=ra_sat*u.degree,
+#                          dec=dec_sat*u.degree, frame='gcrs')
+#     lb_sat = radec_sat.transform_to('geocentrictrueecliptic')
+
+#     # get the obj location
+#     radec_obj = SkyCoord(ra=ra_obj*u.degree,
+#                          dec=dec_obj*u.degree, frame='gcrs')
+#     lb_obj = radec_obj.transform_to('geocentrictrueecliptic')
+
+#     # calculate the angle between sub-satellite point and the earth side
+#     earth_radius = 6371     # km
+#     sat_height = np.sqrt(x_sat**2 + y_sat**2 + z_sat**2)
+#     angle_a = np.arcsin(earth_radius/sat_height) / np.pi * 180
+
+#     # calculate the angle between satellite position and the target position
+#     angle_b = lb_sat.separation(lb_obj)
+
+#     # calculat the earth angle
+#     angle = 180 - angle_a - angle_b.degree
+
+#     return angle
+
+###############################################################################
+
+
+def ill2flux(E, path):
+
+    # use template from sky_bkg (background_spec_hst.dat)
+    filename = path+'MCI_inputData/refs/background_spec_hst.dat'
+    cat_spec = pd.read_csv(filename, sep='\s+', header=None, comment='#')
+    wave0 = cat_spec[0].values       # A
+    spec0 = cat_spec[2].values      # erg/s/cm^2/A/arcsec^2
+
+    # convert erg/s/cm^2/A/arcsec^2 to erg/s/cm^2/A/sr
+    flux1 = spec0 / (1/4.25452e10)
+    # convert erg/s/cm^2/A/sr to W/m^2/sr/um
+    flux2 = flux1 * 10
+
+    # 对接收面积积分，输出单位 W/m^2/nm
+    D = 2   # meter
+    f = 28  # meter, 焦距，转换关系来源于王维notes.
+    flux3 = flux2 * np.pi * D**2 / 4 / f**2 / 10**3
+
+    f = interp1d(wave0, flux3)
+    wave_range = np.arange(3800, 7800)
+    flux3_mean = f(wave_range)
+    delta_lamba = 0.1   # nm
+    E0 = np.sum(flux3_mean * delta_lamba)
+
+    factor = E / E0
+    spec_scaled = factor * spec0
+
+    return wave0, spec_scaled
+
+##############################################################
+
+
+def stray_light(path, time_jd, x_sat, y_sat, z_sat, ra, dec):
+    # EarthShine from straylight
+    sl = StrayLight(path, jtime=time_jd, sat=np.array(
+        [x_sat, y_sat, z_sat]), radec=np.array([(ra*u.degree).value, (dec*u.degree).value]))
+
+    star_e = sl.caculateStarLightFilter(filter='r')
+
+    # angle_earth = earth_angle(time_jd, x_sat, y_sat, z_sat, ra, dec)
+
+    # if angle_earth < 0:
+    #     earth_e = 0
+
+    earthshine_wave0, earthshine_flux0 = ill2flux(star_e, path)
+
+    # sample as mci wavelength
+    wave_mci = np.linspace(2500, 11000, 8501)  # np.arange(2500, 11000, 1)
+
+    f2 = interp1d(earthshine_wave0, earthshine_flux0)
+    star_stray = f2(wave_mci)
+
+    return star_stray
+#################################################################
+
+
+class StrayLight(object):
+
+    def __init__(self, path, jtime=2460843., sat=np.array([0, 0, 0]), radec=np.array([0, 0])):
+
+        self.path = path
+        self.jtime = jtime
+        self.sat = sat
+        self.equator = coord.SkyCoord(
+            radec[0]*u.degree, radec[1]*u.degree, frame='icrs')
+        self.ecliptic = self.equator.transform_to('barycentrictrueecliptic')
+        self.pointing = transRaDec2D(radec[0], radec[1])
+        self.slcdll = ctypes.CDLL(
+            self.path+'MCI_inputData/refs/libstraylight.so')  # dylib
+
+        self.slcdll.Calculate.argtypes = [ctypes.c_double, ctypes.POINTER(ctypes.c_double),
+                                          ctypes.POINTER(ctypes.c_double), ctypes.POINTER(
+                                              ctypes.c_double),
+                                          ctypes.POINTER(ctypes.c_double), ctypes.c_char_p]
+
+        self.slcdll.PointSource.argtypes = [ctypes.c_double, ctypes.POINTER(ctypes.c_double),
+                                            ctypes.POINTER(ctypes.c_double), ctypes.POINTER(
+                                                ctypes.c_double),
+                                            ctypes.POINTER(ctypes.c_double), ctypes.c_char_p]
+
+        self.slcdll.EarthShine.argtypes = [ctypes.c_double, ctypes.POINTER(ctypes.c_double),
+                                           ctypes.POINTER(ctypes.c_double), ctypes.POINTER(
+                                               ctypes.c_double),
+                                           ctypes.POINTER(ctypes.c_double)]
+
+        self.slcdll.Zodiacal.argtypes = [ctypes.c_double, ctypes.POINTER(ctypes.c_double),
+                                         ctypes.POINTER(ctypes.c_double)]
+        self.slcdll.ComposeY.argtypes = [ctypes.POINTER(ctypes.c_double), ctypes.POINTER(ctypes.c_double),
+                                         ctypes.POINTER(ctypes.c_double)]
+        self.slcdll.Init.argtypes = [
+            ctypes.c_char_p, ctypes.c_char_p, ctypes.c_char_p, ctypes.c_char_p]
+        self.deFn = self.path+"MCI_inputData/refs/DE405"
+        self.PSTFn = self.path+"MCI_inputData/refs/PST"
+        self.RFn = self.path+"MCI_inputData/refs/R"
+        self.ZolFn = self.path+"MCI_inputData/refs/Zodiacal"
+        self.brightStarTabFn = self.path+"MCI_inputData/refs/BrightGaia_with_csst_mag"
+
+        self.slcdll.Init(str.encode(self.deFn), str.encode(
+            self.PSTFn), str.encode(self.RFn), str.encode(self.ZolFn))
+
+    def caculateStarLightFilter(self, filter='i'):
+        filterIndex = {'nuv': 0, 'u': 1, 'g': 2,
+                       'r': 3, 'i': 4, 'z': 5, 'y': 6}
+
+        sat = (ctypes.c_double*3)()
+        sat[:] = self.sat
+        ob = (ctypes.c_double*3)()
+        ob[:] = self.pointing
+
+        py1 = (ctypes.c_double*3)()
+        py2 = (ctypes.c_double*3)()
+        self.slcdll.ComposeY(ob, py1, py2)
+
+        star_e1 = (ctypes.c_double*7)()
+        self.slcdll.PointSource(self.jtime, sat, ob, py1,
+                                star_e1, str.encode(self.brightStarTabFn))
+        star_e2 = (ctypes.c_double*7)()
+        self.slcdll.PointSource(self.jtime, sat, ob, py2,
+                                star_e2, str.encode(self.brightStarTabFn))
+
+        band_star_e1 = star_e1[:][filterIndex[filter]]
+        band_star_e2 = star_e2[:][filterIndex[filter]]
+
+        return max(band_star_e1, band_star_e2)
+
+    # def caculateEarthShineFilter(self, filter='i'):
+
+    #     filterIndex = {'nuv': 0, 'u': 1, 'g': 2,
+    #                    'r': 3, 'i': 4, 'z': 5, 'y': 6}
+    #     sat = (ctypes.c_double*3)()
+    #     sat[:] = self.sat
+    #     ob = (ctypes.c_double*3)()
+    #     ob[:] = self.pointing
+
+    #     py1 = (ctypes.c_double*3)()
+    #     py2 = (ctypes.c_double*3)()
+    #     self.slcdll.ComposeY(ob, py1, py2)
+
+    #     earth_e1 = (ctypes.c_double*7)()
+    #     self.slcdll.EarthShine(self.jtime, sat, ob, py1,
+    #                            earth_e1)          # e[7]代表7个波段的照度
+
+    #     earth_e2 = (ctypes.c_double*7)()
+    #     self.slcdll.EarthShine(self.jtime, sat, ob, py2, earth_e2)
+
+    #     band_earth_e1 = earth_e1[:][filterIndex[filter]]
+    #     band_earth_e2 = earth_e2[:][filterIndex[filter]]
+
+    #     return max(band_earth_e1, band_earth_e2)
+
+
+###############################################################################
+# test
+# path='/home/yan/MCI/'
+# time_jd = 2460417.59979167
+# x_sat = -4722.543136
+# y_sat = -1478.219213
+# z_sat = 4595.402769
+# ra = 116.18081536720157
+# dec= 39.42316681016602
+# earthshine0=stray_light(path,time_jd, x_sat, y_sat, z_sat, ra, dec)