alos120Zmanis
This method should be used lechumra only and method returns alos (dawn) calculated using 120 minutes zmaniyos or 1/6th of the day before sunrise or seaLevelSunrise (depending on the isUseElevation setting). This is based on a 24-minute Mil so the time for 5 Mil is 120 minutes which is 1/6th of a day (12 * 60 / 6 = 120). The day is calculated from sea level sunrise to seaLevelSunrise or sunrise to sunset (depending on the isUseElevation. The actual calculation used is sunrise - (shaahZmanisGra * 2). Since this time is extremely early, it should only be used lechumra, such as not eating after this time on a fast day, and not as the start time for mitzvos that can only be performed during the day.
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.