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The waning moon.

At 02:58:26 UT Tuesday 21 February 2017
the waning moon’s phase is

28.82% full

Time Zone:   

Some factors that go into this equation:

Universal Time is 2.99055555555557 in decimal hours.
The Julian date is 2457805.78818767.
The sun’s ecliptic longitude is 332.667626443323 degrees.
Its mean anomaly is 48.46559026582 degrees.
The moon’s true longitude is 267.731266882485 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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