Plot sunrise and sunset times over a year

sunrise_sunset.py

"""
Plot the sun rise, sunset and length of daylight hours over a year
(from a given location). This uses the astropy and astroplan packages.
"""

from matplotlib import pyplot as plt
import numpy as np

from astropy.time import Time, TimeDelta
from astropy import units as u
from astroplan import Observer

# set location
lat = 52.178731 * u.deg
long = 0.222518 * u.deg

obs = Observer(latitude=lat, longitude=long)

# time steps of a day
dt = TimeDelta(1 * u.day)

# start date/time
starttime = Time("2022-01-01 12:00:00", scale="utc")

sunrise = []
sunset = []

for i in range(365):
    # get sunrise time
    srd = obs.sun_rise_time(starttime, which="previous").jd - 0.5
    srd = 24 * (srd - int(srd))  # get hour in day
    sunrise.append(srd)

    # get sunset time
    ssd = obs.sun_set_time(starttime, which="next").jd - 0.5
    ssd = 24 * (ssd - int(ssd))
    sunset.append(ssd)

    starttime += dt
    
fig, ax = plt.subplots(figsize=(8, 4))
ax.plot(range(365), sunrise, label="Sun rise")
ax.plot(range(365), sunset, label="Sun set")
ax.plot(range(365), np.asarray(sunset) - np.asarray(sunrise), label="Length of day")
ax.set_xlabel("Day")
ax.set_ylabel("Time (hours)")
ax.legend()