alos19Degrees
A method to return alos (dawn) calculated when the sun is 19˚ below the eastern geometric horizon before sunrise. Sources:
This is the Rambam 's alos according to
Rabbi Moshe Kosower's Maaglei Tzedek, page 88,
Rabbi Dovid Shor's Ayeles Hashachar Vol. I, page 12,
Rabbi Yaakov Gershon Weiss's Yom Valayla Shel Torah, Ch. 34, p. 222 and
Rabbi Yaakov Shakow's Luach Ikvei Hayom.
Return
the Date representing alos. 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.
See also
ASTRONOMICAL_