alos90Zmanis
Method to return alos (dawn) calculated using 90 minutes zmaniyos or 1/8th of the day before sunrise or sea level sunrise (depending on the isUseElevation setting).
This is based on a 22.5-minute Mil so the time for 4 Mil is 90 minutes which is 1/8th of a day (12 * 60) / 8 = 90.
The day is calculated from sea level sunrise to sea level sunset or sunrise to sunset (depending on the isUseElevation. The actual calculation used is sunrise - (shaahZmanisGra * 1.5).
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.