Thursday night - Mare Crisium in shadow

[AndyWB]

I went out on Thursday night and ended up with some moon gazing. The Mare Crisium was dramatic; like a bite out of the moon. You could see it's rim, but nothing within it except for by this tiny gap in the rim which let the sunlight pour into the crater floor in an arc. It was spectacular, but I've not been able to find out if that notch in the rim has a name; it was kind of between Yerkes and Proclus. I've borrowed this photo of it which is quite good - the gap I saw is pretty much at P and V on this.

Does anyone know if this has a name?

The photo came from here - thank you Ludo Victor

It was a really beautiful sight, but I guess it must rely on exactly the right time, and possibly the right angle to the sun...