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The waning moon.

At 06:29:55 UT Monday 11 December 2017
the waning moon’s phase is

40.22% full

Time Zone:   

Some factors that go into this equation:

Universal Time is 6.51527777777779 in decimal hours.
The Julian date is 2458098.90222453.
The sun’s ecliptic longitude is 259.437607970017 degrees.
Its mean anomaly is 337.4050212346 degrees.
The moon’s true longitude is 1620.71449764948 degrees.

These calculations incorporate the switch to the English New Style (N.S.)—i.e., Gregorian— calendar after Wednesday, 02 September 1752; the next day became Thursday, 14 September, skipping eleven days. (Please also note that, while fairly accurate, these calculations remain a bit buggy.)

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