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Three of the lunar eclipse demos (Python, Java, Kotlin) provided a less than ideal example of efficient computation. They were wasting a lunar eclipse search by calculating it but not printing it. Now after printing exactly 10 lunar eclipses, stop running immediately.
59 lines
1.8 KiB
Python
Executable File
59 lines
1.8 KiB
Python
Executable File
#!/usr/bin/env python3
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#
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# lunar_eclipse.py - by Don Cross - 2020-05-16
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#
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# Example Python program for Astronomy Engine:
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# https://github.com/cosinekitty/astronomy
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#
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# Searches for the next 10 partial/total lunar eclipses after
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# the current date, or a date specified on the command line.
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#
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# To execute, run the command:
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# python3 lunar_eclipse.py [date]
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#
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import sys
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from astronomy import Time, SearchLunarEclipse, NextLunarEclipse, EclipseKind
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def PrintEclipse(e):
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# Calculate beginning/ending of different phases
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# of an eclipse by subtracting/adding the peak time
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# with the number of minutes indicated by the "semi-duration"
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# fields sd_partial and sd_total.
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MINUTES_PER_DAY = 24 * 60
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p1 = e.peak.AddDays(-e.sd_partial / MINUTES_PER_DAY)
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print('{} Partial eclipse begins.'.format(p1))
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if e.sd_total > 0.0:
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t1 = e.peak.AddDays(-e.sd_total / MINUTES_PER_DAY)
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print('{} Total eclipse begins.'.format(t1))
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print('{} Peak of {} eclipse.'.format(e.peak, e.kind.name.lower()))
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if e.sd_total > 0.0:
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t2 = e.peak.AddDays(+e.sd_total / MINUTES_PER_DAY)
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print('{} Total eclipse ends.'.format(t2))
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p2 = e.peak.AddDays(+e.sd_partial / MINUTES_PER_DAY)
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print('{} Partial eclipse ends.'.format(p2))
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print()
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def main(args):
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if len(args) == 1:
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time = Time.Now()
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elif len(args) == 2:
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time = Time.Parse(args[1])
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else:
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print('USAGE: {} [yyyy-mm-ddThh:mm:ssZ]'.format(args[0]))
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return 1
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count = 0
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e = SearchLunarEclipse(time)
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while True:
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if e.kind != EclipseKind.Penumbral:
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PrintEclipse(e)
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count += 1
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if count == 10:
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return 0
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e = NextLunarEclipse(e.peak)
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if __name__ == '__main__':
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sys.exit(main(sys.argv))
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