shaah
Method to return a shaah zmanis (temporal hour) calculated using a 18 dip. This calculation divides the day based on the opinion of the Magen Avraham (MGA) that the day runs from dawn to dusk.
Dawn for this calculation is when the sun is 18 below the eastern geometric horizon before sunrise. Dusk for this is when the sun is 18 below the western geometric horizon after sunset. This day is split into 12 equal parts with each part being a shaah zmanis.
Return
the long millisecond length of a shaah zmanis. If the calculation can't be computed such as northern and southern locations even south of the Arctic Circle and north of the Antarctic Circle where the sun may not reach low enough below the horizon for this calculation, a Long.MIN_VALUE will be returned. See detailed explanation on top of the AstronomicalCalendar documentation.