Flight Sun

Flight Sun is a Python package designed to calculate the proportion of a flight that will be in sunlight.

The sunrise and sunset times of the origin and destination airports are easily obtainable, so for short flights, it can usually be assumed whether a flight is a day or night flight.

However, for long flights, especially those travelling longitudinally, this calculation can be more difficult. For example, a 17-hour flight from London to Perth, Australia can take off and land in daylight, but spend the majority of the flight in darkness.

This package breaks a flight path into segments of day and night, allowing the proportion of a flight that is in sunlight to be calculated.

Features

• GeoJSON rendering of flight path with feature properties for whether the segment is in sunlight
• Integrated IATA and ICAO airport lookups (using airportsdata package). This retrieves the coordinates and local time zones of airports.

Assumptions

• The flight path is a direct great circle route between the origin and destination airports
• The aircraft flies at a constant speed
• Flight altitude is not considered

Installation

Flight Sun can be installed using pip:

pip install flight_sun

Usage

from flight_sun.flight import Flight
from flight_sun.visualisation import generate_geojson
from datetime import datetime
import json

take_off_time = datetime.fromisoformat("2023-02-11 11:50:00")
landing_time = datetime.fromisoformat("2023-02-12 12:25:00")
flight = Flight.from_iata_codes("LHR", "PER", take_off_time, landing_time)

# Get sunlight proportion
print(f"Sunlight proportion: {flight.proportion_in_sunlight():.2%}")

# Get sunlight segments
print("Sunlight segments:")
for segment in flight.light_segments:
    print(f"Sunlight: {segment.sun_up}, start: {segment.start}, end: {segment.end}")

# Render to GeoJSON
geojson = generate_geojson(flight.light_segments)
with open("flight.geojson", "w") as f:
    json.dump(geojson, f)

Example output

Sunlight proportion: 45.23%
Sunlight segments:
Sunlight: True, start: 2023-02-11 11:50:00+00:00, end: 2023-02-11 14:58:00+00:00
Sunlight: False, start: 2023-02-11 14:58:00+00:00, end: 2023-02-12 00:03:00+00:00
Sunlight: True, start: 2023-02-12 00:03:00+00:00, end: 2023-02-12 04:25:00+00:00

Future ideas

• Add support for more complex flight paths (e.g. via waypoints)
• Use real-world flight data to create a better time-distance interpolation function
• Consider the position of the sun in relation to the aircraft i.e. which side of the aircraft is in sunlight