93 lines
3.4 KiB
Python
Executable File
93 lines
3.4 KiB
Python
Executable File
#!/usr/bin/env python
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"""Xaphoon - Displays the phase of the moon as well as other related information."""
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import time
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from argparse import ArgumentParser
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from datetime import datetime, timezone
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from skyfield import almanac
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from skyfield_data import get_skyfield_data_path
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import skyfield.api
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from pyphoon import putmoon
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# Initialize certain skyfield parameters globally
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sf_load = skyfield.api.Loader(get_skyfield_data_path(), expire=False) # loader
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ts = sf_load.timescale(builtin=False) # timescale
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eph = sf_load('de421.bsp') # ephemerides
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earth, sun, moon = eph['Earth'], eph['Sun'], eph['Moon'] # moooon
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def to_timestr(t, date=False, local=True):
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"""Convert a skyfield time to a time string, optionally in the local time zone."""
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t = t.utc_datetime()
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if local:
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t = t.astimezone()
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if date:
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return t.strftime('%Y-%m-%d %H:%M:%S')
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return t.strftime('%H:%M:%S')
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def main():
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"""Main function
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Parses arguments, calculates values, and displays them.
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"""
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parser = ArgumentParser()
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parser.add_argument("lat",
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help="Observer latitude",
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type=float)
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parser.add_argument("lon",
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help="Observer longitude",
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type=float)
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parser.add_argument("elevation",
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help="Observer elevation in meters",
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type=int)
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parser.add_argument("-c", "--columns",
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help="Number of columns for the output to use (default 70)",
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default=70,
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type=int)
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parser.add_argument("-t", "--time",
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help="Unix epoch time to perform calculations for",
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default=time.time(),
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type=int)
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args = parser.parse_args()
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t = ts.from_datetime(datetime.fromtimestamp(args.time, timezone.utc)) # current time
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print(f"Current time: {to_timestr(t)}")
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obs_geo = skyfield.api.wgs84.latlon(args.lat, args.lon,
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elevation_m=args.elevation) # geographic position vector
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obs = earth + obs_geo # barycentric position vector
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moon_apparent = obs.at(t).observe(moon).apparent()
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el, az, _ = moon_apparent.altaz('standard')
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print(f"Az: {az.degrees:.0f}° El: {el.degrees:.0f}°")
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# Find relevant moonrise. el is based on apparent location, so accounts
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# for atmospheric refraction. y shouldn't be needed unless user is near
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# one of the poles, so ignored for now. First [0] discards y (second
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# element of tuple); second [] selects from array of moonrises/moonsets
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if el.degrees > 0:
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# Moon is up. Find last moonrise in the past 24 hours.
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moonrise = almanac.find_risings(obs, moon, t-1, t)[0][-1]
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else:
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# Moon is not up. Find first moonrise in the next 24 hours.
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moonrise = almanac.find_risings(obs, moon, t, t+1)[0][0]
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# Find first moonset in the next 24 hours after moonrise.
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moonset = almanac.find_settings(obs, moon, moonrise, moonrise+1)[0][0]
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print(f"Rise: {to_timestr(moonrise)} Set: {to_timestr(moonset)}")
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transit = almanac.find_transits(obs, moon, moonrise, moonrise+1)[0]
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print(f"Transit: {to_timestr(transit)}")
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phase = almanac.moon_phase(eph, t)
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print(f"Phase: {phase.degrees:.0f}°")
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illum = moon_apparent.fraction_illuminated(sun)
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print(f"Illumination: {illum*100:.0f}%")
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print(putmoon(phase.degrees/360, 21, '@', 'north' if args.lat > 0 else 'south'))
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main()
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