Sexaëteris

A sexaëteris (a.k.a. a hexacontaenneaëteris) is the Greek name for the period within 69 tropical years (a tropical sexayear or sexade) where the Moon phase occurs within 2 weeks earlier.

It corresponds to 853 synodic months, 921.9640993384945 sidereal months, 925.6720522032531 draconic months, 914.1717622827045 anomalistic months, and 25,189.59153240744 days.

It’s just over 65 synodic periods and nearly 6 sidereal revolutions of Jupiter, meaning every new/full moon a sexaëteris apart will be 4 days past conjunction/opposition of Jupiter.

It’s just over 65 synodic periods and close to 6 sidereal revolutions of Jupiter, meaning every new/full moon a sexaëteris apart will be 4 days past conjunction/opposition of Jupiter.
Ben: The first full moon of 2000 is a sexaëteris before the first full moon of 2069.
Gregory: When was the first one again?
Ben: Between January 20 and 21.
Gregory: When’s the first full moon of 2069?
Ben: January 7.
Gregory: Ok.