Twin Lunistices


11/11/2022.

Everybody loves a full moon. We're only three days past the (spectacular, total eclipse) full moon, and now, for one of the upcoming full-moon boreal (northern) lunistices, we're getting a twin moonrise alignment. The nearly full moon will rise at its most northerly spot this cycle both this evening (at 7:23pm) and tomorrow evening (8:14pm).

It will be only 2° (four moon widths) from the maximum risepoint this Major Standstill. And when the moon is overhead at 3:21am tomorrow morning, it will be only 12.8° from being directly above us, and if you are 6 feet tall, your moonshadow will be only 16½ inches.

Let me explain what is going on with the twin moonrises. The path of the moon across the sky is continuous. However, moonrises occur at discrete spots along that path. This means that how far north maximum moonrises occur depends precisely on their timing in the moon's orbit.

On the right side, the maximum moonrise happens to occur right near the peak (the true lunistice) of the orbit, so it is farther north than the moonrises on the left side, which manage to straddle the peak (even though that peak is slightly higher than the peak on the right side). The left-hand side is what is happening today and tomorrow. That is also what is happening during the Fall of the 2024/2025 Major Standstill (which is what the picture is about). The peak occurs at the Fall Equinox with twin moonrises, but the higher moonrise occurs a month later.

One nice thing about twin lunistice moonrises is that you have a second shot at cooperative weather. (But not this time—bad weather both days.)