#!/usr/bin/env python import unittest # Determine whether the equinoxes and solstices which PyEphem predicts # fall within one minute (by the clock) of those predicted by the # United States Naval Observatory. # Data is from http://aa.usno.navy.mil/data/docs/EarthSeasons.php usno_data = """ d h d h m d h m 2000 2000 Perihelion Jan 3 05 Equinoxes Mar 20 07 35 Sept 22 17 27 Aphelion July 4 00 Solstices June 21 01 48 Dec 21 13 37 2001 2001 Perihelion Jan 4 09 Equinoxes Mar 20 13 31 Sept 22 23 04 Aphelion July 4 14 Solstices June 21 07 38 Dec 21 19 21 2002 2002 Perihelion Jan 2 14 Equinoxes Mar 20 19 16 Sept 23 04 55 Aphelion July 6 04 Solstices June 21 13 24 Dec 22 01 14 2003 2003 Perihelion Jan 4 05 Equinoxes Mar 21 01 00 Sept 23 10 47 Aphelion July 4 06 Solstices June 21 19 10 Dec 22 07 04 2004 2004 Perihelion Jan 4 18 Equinoxes Mar 20 06 49 Sept 22 16 30 Aphelion July 5 11 Solstices June 21 00 57 Dec 21 12 42 2005 2005 Perihelion Jan 2 01 Equinoxes Mar 20 12 33 Sept 22 22 23 Aphelion July 5 05 Solstices June 21 06 46 Dec 21 18 35 2006 2006 Perihelion Jan 4 15 Equinoxes Mar 20 18 26 Sept 23 04 03 Aphelion July 3 23 Solstices June 21 12 26 Dec 22 00 22 2007 2007 Perihelion Jan 3 20 Equinoxes Mar 21 00 07 Sept 23 09 51 Aphelion July 7 00 Solstices June 21 18 06 Dec 22 06 08 2008 2008 Perihelion Jan 3 00 Equinoxes Mar 20 05 48 Sept 22 15 44 Aphelion July 4 08 Solstices June 20 23 59 Dec 21 12 04 2009 2009 Perihelion Jan 4 15 Equinoxes Mar 20 11 44 Sept 22 21 18 Aphelion July 4 02 Solstices June 21 05 45 Dec 21 17 47 2010 2010 Perihelion Jan 3 00 Equinoxes Mar 20 17 32 Sept 23 03 09 Aphelion July 6 11 Solstices June 21 11 28 Dec 21 23 38 2011 2011 Perihelion Jan 3 19 Equinoxes Mar 20 23 21 Sept 23 09 04 Aphelion July 4 15 Solstices June 21 17 16 Dec 22 05 30 2012 2012 Perihelion Jan 5 00 Equinoxes Mar 20 05 14 Sept 22 14 49 Aphelion July 5 03 Solstices June 20 23 09 Dec 21 11 11 2013 2013 Perihelion Jan 2 05 Equinoxes Mar 20 11 02 Sept 22 20 44 Aphelion July 5 15 Solstices June 21 05 04 Dec 21 17 11 2014 2014 Perihelion Jan 4 12 Equinoxes Mar 20 16 57 Sept 23 02 29 Aphelion July 4 00 Solstices June 21 10 51 Dec 21 23 03 2015 2015 Perihelion Jan 4 07 Equinoxes Mar 20 22 45 Sept 23 08 20 Aphelion July 6 19 Solstices June 21 16 38 Dec 22 04 48 2016 2016 Perihelion Jan 2 23 Equinoxes Mar 20 04 30 Sept 22 14 21 Aphelion July 4 16 Solstices June 20 22 34 Dec 21 10 44 2017 2017 Perihelion Jan 4 14 Equinoxes Mar 20 10 28 Sept 22 20 02 Aphelion July 3 20 Solstices June 21 04 24 Dec 21 16 28 2018 2018 Perihelion Jan 3 06 Equinoxes Mar 20 16 15 Sept 23 01 54 Aphelion July 6 17 Solstices June 21 10 07 Dec 21 22 22 2019 2019 Perihelion Jan 3 05 Equinoxes Mar 20 21 58 Sept 23 07 50 Aphelion July 4 22 Solstices June 21 15 54 Dec 22 04 19 2020 2020 Perihelion Jan 5 08 Equinoxes Mar 20 03 49 Sept 22 13 30 Aphelion July 4 12 Solstices June 20 21 43 Dec 21 10 02 """ # import datetime, time import ephem # Since users might be in another locale, we have to translate the # month into an integer on our own. month_ints = { 'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6, 'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12, } sun = ephem.Sun() def to_date(year, monthname, day, hour, minute): mi = month_ints[monthname[:3]] s = '%s/%s/%s %s:%s' % (year, mi, day, hour, minute) dt = datetime.datetime(*time.strptime(s, '%Y/%m/%d %H:%M')[0:5]) return ephem.date(dt) def sequence_of_events(data): seq = [] for line in data.split('\n'): fields = line.split() if line.startswith('2'): fields = line.split() year = int(fields[0]) # '2001' or whatever elif line.startswith('Perihelion'): seq.append((to_date(year, *fields[5:9]), 'vernal equinox')) seq.append((to_date(year, *fields[9:13]), 'autumnal equinox')) elif line.startswith('Aphelion'): seq.append((to_date(year, *fields[5:9]), 'summer solstice')) seq.append((to_date(year, *fields[9:13]), 'winter solstice')) seq.sort() return seq def run_test(seq, step, functions): if step > 0: date = seq[0][0] - 1 # one day earlier than first event r = range(0, len(seq)) else: date = seq[-1][0] + 1 # one day after last event r = range(len(seq) - 1, -1, -1) for i in r: usno_date = seq[i][0] function = functions[i % len(functions)] date = function(date) if abs(usno_date - date) > ephem.minute: raise AssertionError( 'The USNO predicts a %s at %s but PyEphem at %s' % (seq[i][1], usno_date, date)) def process_usno(data): seq = sequence_of_events(data) run_test(seq, +1, (ephem.next_equinox, ephem.next_solstice, ephem.next_equinox, ephem.next_solstice, )) run_test(seq, +1, (ephem.next_vernal_equinox, ephem.next_summer_solstice, ephem.next_autumnal_equinox, ephem.next_winter_solstice, )) run_test(seq, -1, (ephem.previous_equinox, ephem.previous_solstice, ephem.previous_equinox, ephem.previous_solstice, )) run_test(seq, -1, (ephem.previous_vernal_equinox, ephem.previous_summer_solstice, ephem.previous_autumnal_equinox, ephem.previous_winter_solstice, )) class UsnoEquinoxesTests(unittest.TestCase): def test_equinoxes(self): process_usno(usno_data)