To look up the phase of the moon for any (Common Era) date,
just fill out the form below, then hit “Find Phase.”

The new moon.

At 01:01:33 UT Thursday 10 June 2021
the moon was


Some factors that go into this equation:

Universal Time is 1.0425 in decimal hours.
The Julian date was 2459375.5015339.
The sun’s ecliptic longitude was 79.403845725107 degrees.
Its mean anomaly was 155.8519358008 degrees.
The moon’s mean longitude on 00 January 1990 was 318.351648 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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