When was the length of the moons mean sidereal month 27.416 days. Help needed in calc

[Edwin1974]

Hi

Im trying to match up a date with when the length of the moons mean sidereal month was equal to 27.416 days. Can anyone please assist in teaching me how to go about calculating that ???

Kind regards
Edwin.

[Hornblower]

Hi

Im trying to match up a date with when the length of the moons mean sidereal month was equal to 27.416 days. Can anyone please assist in teaching me how to go about calculating that ???

Kind regards
Edwin.

By "day" do you mean the current mean solar day or whatever it was at some time in the past? Both the day and the month were shorter in the past, perhaps by different factors.