add calculate pointing center tools by defining chip center ra dec

tools/get_pointing_accurcy.py

+
+from pylab import *
+import math, sys, numpy as np
+import astropy.coordinates as coord
+from astropy.coordinates import SkyCoord
+from astropy import wcs, units as u
+from observation_sim.config.header import ImageHeader
+from observation_sim.instruments import Telescope, Chip, FilterParam, Filter, FocalPlane
+
+
+def transRaDec2D(ra, dec):
+    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 ecl2radec(lon_ecl, lat_ecl):
+    ## convert from ecliptic coordinates to equatorial coordinates
+    c_ecl = SkyCoord(
+        lon=lon_ecl * u.degree, lat=lat_ecl * u.degree, frame="barycentrictrueecliptic"
+    )
+    c_eq = c_ecl.transform_to("icrs")
+    ra_eq, dec_eq = c_eq.ra.degree, c_eq.dec.degree
+    return ra_eq, dec_eq
+
+
+def radec2ecl(ra, dec):
+    ## convert from equatorial coordinates to ecliptic coordinates
+    c_eq = SkyCoord(ra=ra * u.degree, dec=dec * u.degree, frame="icrs")
+    c_ecl = c_eq.transform_to("barycentrictrueecliptic")
+    lon_ecl, lat_ecl = c_ecl.lon.degree, c_ecl.lat.degree
+    return lon_ecl, lat_ecl
+
+def cal_FoVcenter_1P_equatorial(ra_FieldCenter, dec_FieldCenter, chipID = 1, pa = -23.5):
+
+    ### [ra_FieldCenter, dec_FieldCenter] is the center ra, dec of calibration fileds, such as: NEP, NGC 6397, etc.
+    ### [ra_ChipCenter, dec_ChipCenter] is the center ra, dec of the Chip center.
+    ### [ra_PointCenter, dec_PointCenter] is the telescope pointing center.
+    ## Calculate PA angle
+    chip = Chip(chipID)
+
+    h_ext = ImageHeader.generateExtensionHeader(
+        chip=chip,
+        xlen=chip.npix_x,
+        ylen=chip.npix_y,
+        ra=(ra_FieldCenter * u.degree).value, 
+        dec=(dec_FieldCenter * u.degree).value,
+        pa=pa,
+        gain=chip.gain,
+        readout=chip.read_noise,
+        dark=chip.dark_noise,
+        saturation=90000,
+        pixel_scale=chip.pix_scale,
+        pixel_size=chip.pix_size,
+        xcen=chip.x_cen,
+        ycen=chip.y_cen,
+        )
+
+    # assume that the telescope point to the sky center; then abtain the chip center under this situation; then calculate the differenc between the assumed telescope center and chip center; then add this difference to the sky center
+
+    wcs_h = wcs.WCS(h_ext)
+    pixs = np.array([[4608, 4616]])
+    world_point = wcs_h.wcs_pix2world(pixs, 0)
+    ra_ChipCenter, dec_ChipCenter = world_point[0][0], world_point[0][1]
+
+    d_ra = ra_FieldCenter - ra_ChipCenter
+    d_dec = dec_FieldCenter - dec_ChipCenter
+
+    ra_PointCenter = ra_FieldCenter + d_ra
+    dec_PointCenter = dec_FieldCenter + d_dec
+
+    lon_ecl_PointCenter, lat_ecl_PointCenter = radec2ecl(
+        ra_PointCenter, dec_PointCenter
+    )
+
+    return ra_PointCenter, dec_PointCenter, lon_ecl_PointCenter, lat_ecl_PointCenter
+
+def cal_FoVcenter_1P_ecliptic(lon_ecl_FieldCenter, lat_ecl_FieldCenter, chipID = 1, pa = -23.5):
+
+    ### [ra_FieldCenter, dec_FieldCenter] is the center ra, dec of calibration fileds, such as: NEP, NGC 6397, etc.
+    ### [ra_ChipCenter, dec_ChipCenter] is the center ra, dec of the Chip center.
+    ### [ra_PointCenter, dec_PointCenter] is the telescope pointing center.
+
+    ra_FieldCenter, dec_FieldCenter = ecl2radec(
+        lon_ecl_FieldCenter, lat_ecl_FieldCenter
+    )
+
+    ## Calculate PA angle
+    chip = Chip(chipID)
+
+    h_ext = ImageHeader.generateExtensionHeader(
+        chip=chip,
+        xlen=chip.npix_x,
+        ylen=chip.npix_y,
+        ra=(ra_FieldCenter * u.degree).value, 
+        dec=(dec_FieldCenter * u.degree).value,
+        pa=pa,
+        gain=chip.gain,
+        readout=chip.read_noise,
+        dark=chip.dark_noise,
+        saturation=90000,
+        pixel_scale=chip.pix_scale,
+        pixel_size=chip.pix_size,
+        xcen=chip.x_cen,
+        ycen=chip.y_cen,
+        )
+
+    # assume that the telescope point to the sky center; then abtain the chip center under this situation; then calculate the differenc between the assumed telescope center and chip center; then add this difference to the sky center
+
+    wcs_h = wcs.WCS(h_ext)
+    pixs = np.array([[4608, 4616]])
+    world_point = wcs_h.wcs_pix2world(pixs, 0)
+    ra_ChipCenter, dec_ChipCenter = world_point[0][0], world_point[0][1]
+
+    d_ra = ra_FieldCenter - ra_ChipCenter
+    d_dec = dec_FieldCenter - dec_ChipCenter
+
+    ra_PointCenter = ra_FieldCenter + d_ra
+    dec_PointCenter = dec_FieldCenter + d_dec
+
+    lon_ecl_PointCenter, lat_ecl_PointCenter = radec2ecl(
+        ra_PointCenter, dec_PointCenter
+    )
+
+    return ra_PointCenter, dec_PointCenter, lon_ecl_PointCenter, lat_ecl_PointCenter
+
+def getChipCenterRaDec(chipID = 1, p_ra = 60., p_dec = -40.):
+    chip = Chip(chipID)
+
+    h_ext = ImageHeader.generateExtensionHeader(
+        chip=chip,
+        xlen=chip.npix_x,
+        ylen=chip.npix_y,
+        ra=(p_ra * u.degree).value, 
+        dec=(p_dec * u.degree).value,
+        pa=pa,
+        gain=chip.gain,
+        readout=chip.read_noise,
+        dark=chip.dark_noise,
+        saturation=90000,
+        pixel_scale=chip.pix_scale,
+        pixel_size=chip.pix_size,
+        xcen=chip.x_cen,
+        ycen=chip.y_cen,
+        )
+    wcs_h = wcs.WCS(h_ext)
+    pixs = np.array([[4608, 4616]])
+    world_point = wcs_h.wcs_pix2world(pixs, 0)
+    RA_chip, Dec_chip = world_point[0][0], world_point[0][1]
+    return RA_chip, Dec_chip
+
+if __name__ == '__main__':
+    ra_input, dec_input = 270.00000, 66.56000  # NEP
+    pa = 23.5
+    # chipid = 2
+
+    for chipid in np.arange(1,31,1):
+        ra, dec, lon_ecl, lat_ecl = cal_FoVcenter_1P_equatorial(
+                    ra_input, dec_input,chipID=chipid, pa=pa)
+
+        print("chip id is %d, chip center [ra,dec] is [%f, %f], pointing center calculated [ra,dec] is [%f, %f]"%(chipid, ra_input, dec_input, ra, dec))
+        #for check the result
+        # testRA, testDec = getChipCenterRaDec(chipID = chipid, p_ra = ra, p_dec = dec)
+        # print(ra_input-testRA, dec_input-testDec)
+