def extinctionCorrectionApparentToTrue(mags, x_data, y_data, jd, platepar):
""" Compute true magnitudes by applying extinction correction to apparent magnitudes.
Arguments:
mags: [list] A list of apparent magnitudes.
x_data: [list] A list of pixel columns.
y_data: [list] A list of pixel rows.
jd: [float] Julian date.
platepar: [Platepar object]
Return:
corrected_mags: [list] A list of extinction corrected mangitudes.
"""
### Compute star elevations above the horizon (epoch of date, true) ###
# Compute RA/Dec in J2000
_, ra_data, dec_data, _ = xyToRaDecPP(len(x_data)*[jd2Date(jd)], x_data, y_data, len(x_data)*[1], \
platepar, extinction_correction=False)
# Compute elevation above the horizon
elevation_data = []
for ra, dec in zip(ra_data, dec_data):
# Precess to epoch of date
ra, dec = equatorialCoordPrecession(J2000_JD.days, jd, np.radians(ra),
np.radians(dec))
# Compute elevation
_, elev = raDec2AltAz(np.degrees(ra), np.degrees(dec), jd,
platepar.lat, platepar.lon)
if elev < 0:
elev = 0
elevation_data.append(elev)
### ###
# Correct catalog magnitudes for extinction
extinction_correction = atmosphericExtinctionCorrection(np.array(elevation_data), platepar.elev) \
- atmosphericExtinctionCorrection(90, platepar.elev)
corrected_mags = np.array(
mags) - platepar.extinction_scale * extinction_correction
return corrected_mags
def extinctionCorrectionTrueToApparent(catalog_mags, ra_data, dec_data, jd,
platepar):
""" Compute apparent magnitudes by applying extinction correction to catalog magnitudes.
Arguments:
catalog_mags: [list] A list of catalog magnitudes.
ra_data: [list] A list of catalog right ascensions (J2000) in degrees.
dec_data: [list] A list of catalog declinations (J2000) in degrees.
jd: [float] Julian date.
platepar: [Platepar object]
Return:
corrected_catalog_mags: [list] Extinction corrected catalog magnitudes.
"""
### Compute star elevations above the horizon (epoch of date, true) ###
# Compute elevation above the horizon
elevation_data = []
for ra, dec in zip(ra_data, dec_data):
# Precess to epoch of date
ra, dec = equatorialCoordPrecession(J2000_JD.days, jd, np.radians(ra),
np.radians(dec))
# Compute elevation
_, elev = raDec2AltAz(np.degrees(ra), np.degrees(dec), jd,
platepar.lat, platepar.lon)
if elev < 0:
elev = 0
elevation_data.append(elev)
### ###
# Correct catalog magnitudes for extinction
extinction_correction = atmosphericExtinctionCorrection(np.array(elevation_data), platepar.elev) \
- atmosphericExtinctionCorrection(90, platepar.elev)
corrected_catalog_mags = np.array(
catalog_mags) + platepar.extinction_scale * extinction_correction
return corrected_catalog_mags