To look up the phase of the moon for any date,
just fill out the form below, then hit "Find Phase."

The waning moon.

At 20:18:30 UT Tuesday 17 October 2017
the waning moon’s phase is

4.01% full

Time Zone:   

Some factors that go into this equation:

Universal Time is 20.325 in decimal hours.
The Julian date is 2458043.54005627.
The sun’s ecliptic longitude is 204.66979315391 degrees.
Its mean anomaly is 283.7615631417 degrees.
The moon’s true longitude is 901.579418372184 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.)

 Send comments to

© 1997–2017 by 3IP.