tzais96
A method to return tzais (dusk) calculated as 96 minutes after sea level sunset. For information on how this is calculated see the comments on alos96.
Return
the Date representing the time. If the calculation can't be computed such as in the Arctic Circle where there is at least one day a year where the sun does not rise, and one where it does not set, a null will be returned. See detailed explanation on top of the AstronomicalCalendar documentation.