alos
Returns alos (dawn) based on the time when the sun is 16.1˚ below the eastern geometric horizon before sunrise. This is based on the calculation that the time between dawn and sunrise (and sunset to nightfall) is 72 minutes, the time that is takes to walk 4 mil at 18 minutes a mil (Rambam and others). The sun's position at 72 minutes before sunrise in Jerusalem on the [around the equinox /
equilux](https://kosherjava.com/2022/01/12/equinox-vs-equilux-zmanim-calculations/) is 16.1 below AstronomicalCalendar.GEOMETRIC_ZENITH.
Return
The Date of dawn. 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 null will be returned. See detailed explanation on top of the AstronomicalCalendar documentation.