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astropy を使って、与えられた場所での与えられた時間での太陽の座標を調べ るには、以下のようにすればよいようでござる。
#!/usr/pkg/bin/python3.9 # # Time-stamp: <2022/07/03 10:40:02 (CST) daisuke> # # importing argparse module import argparse # importing astropy module import astropy.units import astropy.time import astropy.coordinates # importing ssl module import ssl # allow insecure downloading ssl._create_default_https_context = ssl._create_unverified_context # units unit_m = astropy.units.m # constructing parser object desc = "position of the Sun in (RA, Dec) at given location and time" parser = argparse.ArgumentParser (description=desc) # adding arguments parser.add_argument ('-l', '--longitude', default='+121d11m12s', \ help='longitude of observing site in format "+121d11m12s"') parser.add_argument ('-b', '--latitude', default='+24d58m12s', \ help='latitude of observing site in format "+24d58m12s"') parser.add_argument ('-a', '--altitude', type=float, default=151.6, \ help='altitude above sea-level in metre') parser.add_argument ('-t', '--datetime', default='2000-01-01T12:00:00.000', \ help='date/time in UT in "YYYY-MM-DDThh:mm:ss.sss" format') # command-line argument analysis args = parser.parse_args () # input parameters site_lon = args.longitude site_lat = args.latitude site_alt = args.altitude * unit_m datetime_str = args.datetime # printing input parameters print ("#") print ("# input parameters") print ("#") print ("# Location:") print ("# longitude =", site_lon) print ("# latitude =", site_lat) print ("# altitude =", site_alt) print ("# Date/Time:") print ("# date/time (UT) =", datetime_str) print ("#") # location object location = astropy.coordinates.EarthLocation.from_geodetic \ (site_lon, site_lat, site_alt) # time object datetime = astropy.time.Time (datetime_str, scale='utc') # using DE430 astropy.coordinates.solar_system_ephemeris.set ('de430') # position of the Sun sun = astropy.coordinates.get_body ('sun', datetime, location) (sun_ra, sun_dec) = sun.to_string ('hmsdms').split () # conversion from equatorial into ecliptic sun_ecliptic = sun.transform_to \ (astropy.coordinates.GeocentricMeanEcliptic (obstime=datetime) ) sun_lambda = sun_ecliptic.lon sun_beta = sun_ecliptic.lat # conversion from equatorial into horizontal sun_altaz = sun.transform_to \ (astropy.coordinates.AltAz (obstime=datetime, location=location) ) sun_alt = sun_altaz.alt sun_az = sun_altaz.az # printing position of the Sun print ("Sun:") print (" Equatorial: (RA, Dec) = (%s, %s)" % (sun_ra, sun_dec) ) print (" Ecliptic: (lambda, beta) = (%s, %s)" % (sun_lambda, sun_beta) ) print (" AltAz: (Az, Alt) = (%s, %s)" % (sun_az, sun_alt) )
実行してみると、以下のようになるでござる。
% ./astroplan_sample_03.py -h usage: astroplan_sample_03.py [-h] [-l LONGITUDE] [-b LATITUDE] [-a ALTITUDE] [-t DATETIME] position of the Sun in (RA, Dec) at given location and time optional arguments: -h, --help show this help message and exit -l LONGITUDE, --longitude LONGITUDE longitude of observing site in format "+121d11m12s" -b LATITUDE, --latitude LATITUDE latitude of observing site in format "+24d58m12s" -a ALTITUDE, --altitude ALTITUDE altitude above sea-level in metre -t DATETIME, --datetime DATETIME date/time in UT in "YYYY-MM-DDThh:mm:ss.sss" format % ./astroplan_sample_03.py -t 2022-07-03T04:00:00 # # input parameters # # Location: # longitude = +121d11m12s # latitude = +24d58m12s # altitude = 151.6 m # Date/Time: # date/time (UT) = 2022-07-03T04:00:00 # Sun: Equatorial: (RA, Dec) = (06h47m32.47569282s, +22d59m12.51257435s) Ecliptic: (lambda, beta) = (100d55m45.62031139s, -0d00m09.3442212s) AltAz: (Az, Alt) = (183d23m17.48446394s, 87d59m20.74531916s)