rewrite with skyfield
parent
2184a5b077
commit
bc5f5932f1
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@ -94,7 +94,7 @@ def putmoon(pctphase, lines, atfiller, hemisphere): # pylint: disable=too-many-
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# rotate char upside-down if needed
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char = char.translate(str.maketrans("().`_'",
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")(`.^,"))
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"!!!!!!"))
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if char != '@':
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putchar(char)
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185
xaphoon.py
185
xaphoon.py
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@ -1,103 +1,43 @@
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#!/usr/bin/env python
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from datetime import datetime, timezone
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import math
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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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import ephem
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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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# Second resolution for culmination/illumination calculations
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DAY_INCREMENT=1/86400
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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_deg(rad):
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"""Convert radians to a displayable integer number of degrees."""
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return round(math.degrees(rad))
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def to_timestr(date, local=True):
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"""Convert a pyephem date to a time string in the local time zone."""
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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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date = ephem.localtime(date)
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else:
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date = date.datetime()
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return date.strftime("%H:%M:%S")
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def find_target_rising(moon, me):
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"""Return the relevant moonrise to base display and calculations off of."""
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if moon.alt == 0: # i would love a better way to do this
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me = me.copy()
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me.date = me.previous_rising(moon)
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return me.next_rising(moon)
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if moon.alt > 0:
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return me.previous_rising(moon)
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# moon.alt < 0
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return me.next_rising(moon)
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def cmp_culmination(moon, me, t):
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"""Determine whether the culmination is before, after, or at t.
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Returns 0 if t is the culmination, -1 if t if culmination is before t, or 1
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if culmination is after t. Assumes there is exactly one peak elevation,
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which seems to cause error of up to about 7 seconds due to float precision.
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"""
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me.date = t - DAY_INCREMENT
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moon.compute(me)
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e1 = moon.alt
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me.date = t
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moon.compute(me)
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e2 = moon.alt
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me.date = t + DAY_INCREMENT
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moon.compute(me)
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e3 = moon.alt
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if e1 > e2:
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return -1
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if e3 > e2:
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return 1
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return 0
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def find_culmination(moon, me, rising, setting):
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"""Finds culmination via binary search.
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Assumes rising and setting are from same pass.
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"""
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moon = moon.copy()
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me = me.copy()
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t1 = rising
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t3 = setting
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while True:
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t2 = (t1 + t3) / 2
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match cmp_culmination(moon,me,t2):
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case 0: return ephem.date(t2)
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case -1: t3 = t2
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case 1: t1 = t2
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def cmp_illumination(moon, me, t):
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"""Determine whether the moon is waxing, waning, or either full or new.
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Returns 0 if the moon is either full or new, -1 if moon is waning, or 1
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if moon is waxing.
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"""
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moon = moon.copy()
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me = me.copy()
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me.date = t - DAY_INCREMENT
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moon.compute(me)
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i1 = moon.moon_phase
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me.date = t + DAY_INCREMENT
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moon.compute(me)
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i2 = moon.moon_phase
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if i1 > i2:
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return -1
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if i1 < i2:
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return 1
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return 0
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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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parser.add_argument("long",
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help="Observer longitude")
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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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@ -111,47 +51,42 @@ def main():
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type=int)
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args = parser.parse_args()
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now = ephem.date(datetime.fromtimestamp(args.time, timezone.utc))
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print(f"Current time: {to_timestr(now)}")
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t = ts.from_datetime(datetime.fromtimestamp(args.time, timezone.utc)) # current time
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me = ephem.Observer()
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me.date = now
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me.lat = args.lat
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me.lon = args.long
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me.elevation = args.elevation
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print(f"Current time: {to_timestr(t)}")
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moon = ephem.Moon(me)
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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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az = to_deg(moon.az)
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el = to_deg(moon.alt)
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print(f"Az: {az}° El: {el}°")
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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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rising = find_target_rising(moon, me)
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setting = me.next_setting(moon)
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print (f"Rise: {to_timestr(rising)} Set: {to_timestr(setting)}")
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culm = find_culmination(moon, me, rising, setting)
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print(f"Culmination: {to_timestr(culm)}")
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direction = cmp_illumination(moon, me, now)
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match direction:
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case -1:
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direction_indicator = '-'
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case 0:
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direction_indicator = ''
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case 1:
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direction_indicator = '+'
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print(f"Phase: {moon.moon_phase:.0%}{direction_indicator}")
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# Convert illumination percentage and waxing/waning status to percent through full cycle
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if direction < 0: # waning
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full_cycle_phase = 1 - (moon.moon_phase / 2)
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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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full_cycle_phase = moon.moon_phase / 2
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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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print(putmoon(full_cycle_phase, 20, '@', 'northern' if me.lat > 0 else 'southern'))
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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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