alos120
This method should be used lechumra only and returns alos (dawn) calculated using 120 minutes before sea level sunrise based on the time to walk the distance of 5 Mil(Ula) at 24 minutes a Mil.
Time based offset calculations for alos are based on the* opinion of the *Rishonim who stated that the time of the neshef (time between dawn and sunrise) does not vary by the time of year or location but purely depends on the time it takes to walk the distance of 5 Mil(Ula). 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.