1,336. An Arc of Visibility from 12 to 14 Degrees

Rabbi Jack Abramowitz

Hilchos Kiddush HaChodesh 17:20

If the arc of visibility is between 12 and 13 degrees, or greater than 13, and the first longitude is 10 degrees or higher, the moon will certainly be visible. If the arc or the first longitude is smaller than this, the moon will not be visible.

Hilchos Kiddush HaChodesh 17:21

If the arc of visibility is between 13 and 14 degrees, or greater than 14, and the first longitude is nine degrees or higher, the moon will certainly be visible. If the arc or the first longitude is smaller than this, the moon will not be visible. That’s all the visibility limits.