Sunset and Altitude for Shakespeare's Plays

shakes.py

# Caveat, the dates included are Julian but PyEphem and Python only really know about Gregorian.
# Additionally, not all of these performances were at The Globe so we should be moving the Observer
# accordingly. It still largely proves the hypothesis.

import argparse
from datetime import datetime

import ephem
from prettytable import PrettyTable


def shakespeare_had_candles(args):
    time_of_day = args.time_of_day
    show_altitude = args.show_altitude

    hour, minute, second = map(int, time_of_day.split(':'))

    plays = [
        {'name': 'Henry VI, Part I', 'performance_date': datetime(1592, 03, 03)},
        {'name': 'Titus Andronicus', 'performance_date': datetime(1594, 1, 23)},
        {'name': 'Taming of the Shrew', 'performance_date': datetime(1594, 6, 13)},
        {'name': 'The Comedy of Errors', 'performance_date': datetime(1594, 12, 28)},
        {'name': "Love's Labours Lost", 'performance_date': datetime(1597, 12, 26)},
        {'name': 'Julius Caesar', 'performance_date': datetime(1599, 10, 21)},
        {'name': 'Henry IV, Part I', 'performance_date': datetime(1600, 3, 6)},
        {'name': 'Richard II', 'performance_date': datetime(1601, 2, 7)},
        {'name': 'Twelfth Night', 'performance_date': datetime(1602, 2, 2)},
        {'name': 'Othello', 'performance_date': datetime(1604, 11, 1)},
        {'name': 'Troilus and Cressida', 'performance_date': datetime(1604, 2, 7)},
        {'name': 'Merry Wives of Windsor', 'performance_date': datetime(1604, 11, 4)},
        {'name': 'Measure for Measure', 'performance_date': datetime(1604, 12, 26)},
        {'name': 'Henry V', 'performance_date': datetime(1605, 1, 7)},
        {'name': 'Merchant of Venice', 'performance_date': datetime(1605, 2, 10)},
        {'name': 'King Lear', 'performance_date': datetime(1606, 12, 26)},
        {'name': 'The Tempest', 'performance_date': datetime(1611, 11, 1)},
        {'name': 'Henry VIII', 'performance_date': datetime(1613, 6, 29)}
    ]

    globe = ephem.Observer()
    globe.lat = '51.5069841'
    globe.lon = '-0.0944368'
    globe.elevation = 14

    sun = ephem.Sun()

    table_headers = ['Play',
        #'Curtain Up',
        'Sunset',
        'Time Difference',
        'Light',
        'Twilight Date',
        'T Light']
    if show_altitude:
        table_headers.append("Sun's Altitude")

    x = PrettyTable(table_headers)
    x.align['Play'] = 'l'
    #x.align['Curtain Up'] = 'r'
    x.align['Sunset'] = 'r'
    x.align['Time Difference'] = 'l'
    x.align['Candles'] = 'l'
    x.align['Twilight Date'] = 'r'
    x.align['Twilight Candles'] = 'l'
    if show_altitude:
        x.align["Sun's Altitude"] = 'l'
    x.padding_width = 2

    candle_plays = 0
    twilight_plays = 0

    for play in plays:
        # set horizon for London/Southwark/The Globe
        globe.horizon = '-0:34'
        globe.date = play['performance_date'].replace(hour=hour, minute=minute, second=second).\
                        isoformat().replace('T', ' ')
        start_date = globe.date

        # compute sun's origin position
        sun.compute(globe)

        # get sun's altitude at highest point in our time range
        if show_altitude:
            most_light = str(sun.alt)

        # get the datetime of the next setting
        setting_date = globe.next_setting(sun)

        # change horizon so we can calculate twilight (civil)
        globe.horizon = '-6'
        twilight_date = globe.next_setting(sun, use_center=True)

        # determine of time interval means we'll need candles
        diff = setting_date.datetime() - start_date.datetime()
        if diff.total_seconds() > 10800:
            candles = 'N'
        else:
            candles = 'Y'
            candle_plays += 1

        # given the dying light of twilight will we still need candles
        t_diff = twilight_date.datetime() - start_date.datetime()
        if t_diff.total_seconds() > 10800:
            twilight_candles = 'N'
        else:
            twilight_candles = 'Y'
            twilight_plays += 1

        # add this data to output rows
        word_diff = '%d hours, %d minutes' % (diff.seconds // 3600, (diff.seconds // 60) % 60)
        row_items = [play['name'],
            #start_date,
            setting_date,
            word_diff,
            candles,
            twilight_date,
            twilight_candles]
        if show_altitude:
            row_items.append(most_light)
        x.add_row(row_items)

    print "Total Performances: %d" % len(plays)
    print "Candle Performances: %d" % candle_plays
    print "Twilight Candle Performances: %d" % twilight_plays

    print x

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description="Did Shakespeare need candles?.")
    parser.add_argument('-t', action="store", dest='time_of_day', type=str,
                    help="What time of day in (HH:MM:SS) format?")
    parser.add_argument('-a', dest='show_altitude', help="Want to see the altitude?",
                    action="store_true", default=False)
    args = parser.parse_args()

    shakespeare_had_candles(args)