mirror of
https://gitlvb.teallvbs.xyz/IQ.Lvbs/IQ.Pilot.git
synced 2026-07-24 21:12:05 +08:00
IQ.Lvbs CI [bot]
37 lines
1.7 KiB
Python
37 lines
1.7 KiB
Python
import math
|
|
from datetime import UTC, datetime
|
|
|
|
_J2000 = datetime(2000, 1, 1, 12, 0, 0, tzinfo=UTC)
|
|
SUNSET_ELEVATION_DEG = -0.833 # standard sunset/sunrise threshold, corrected for atmospheric refraction
|
|
|
|
|
|
def sun_elevation_deg(lat: float, lon: float, dt_utc: datetime | None = None) -> float:
|
|
"""Low-precision solar elevation angle (accurate to well under a degree), per the
|
|
standard Meeus-derived approximation. lat/lon in degrees (lon positive east)."""
|
|
dt_utc = dt_utc or datetime.now(UTC)
|
|
n = (dt_utc - _J2000).total_seconds() / 86400.0
|
|
|
|
mean_lon = math.radians((280.460 + 0.9856474 * n) % 360)
|
|
mean_anomaly = math.radians((357.528 + 0.9856003 * n) % 360)
|
|
ecliptic_lon = (mean_lon + math.radians(1.915) * math.sin(mean_anomaly)
|
|
+ math.radians(0.020) * math.sin(2 * mean_anomaly))
|
|
obliquity = math.radians(23.439 - 0.0000004 * n)
|
|
|
|
declination = math.asin(math.sin(obliquity) * math.sin(ecliptic_lon))
|
|
right_ascension = math.atan2(math.cos(obliquity) * math.sin(ecliptic_lon), math.cos(ecliptic_lon))
|
|
|
|
equation_of_time_deg = math.degrees(mean_lon - right_ascension)
|
|
equation_of_time_deg = (equation_of_time_deg + 180) % 360 - 180
|
|
|
|
utc_hours = dt_utc.hour + dt_utc.minute / 60 + dt_utc.second / 3600
|
|
hour_angle = math.radians(15 * (utc_hours - 12) + lon + equation_of_time_deg)
|
|
|
|
lat_rad = math.radians(lat)
|
|
elevation = math.asin(math.sin(lat_rad) * math.sin(declination)
|
|
+ math.cos(lat_rad) * math.cos(declination) * math.cos(hour_angle))
|
|
return math.degrees(elevation)
|
|
|
|
|
|
def is_after_sunset(lat: float, lon: float, dt_utc: datetime | None = None) -> bool:
|
|
return sun_elevation_deg(lat, lon, dt_utc) < SUNSET_ELEVATION_DEG
|