Need help from Lunar astronomers!

I have a “toy” telescope that is good enough to see on the moon and I love to look at its features on a night like this. But I have some need of help from lunar experts.

I was looking at Sinus iridium tonight, which as you must know is located in the north-west quadrant at about 45 degrees N and 28-38 degrees west. The Jura mountains that frame the sinus are exactly at the dark-line of the moon tonight, so that only their peaks arelit up, making them look funny. My problem is that my map of the moon does not show the existence of a rather large (about 41 km) crater calld Crater Maupertius that occurs in that peninsula of mountains that form a V at the eastern edge of Sinus Iridium.

My book dates from 1978. Is that crater recent? Is Plato younger because it is so clear and distinct?

Finally, I once read a story about some English Monks around 1200 who were looking at the Moon (crescent that night) and suddenly saw a ray of light shoot off of one of its horns, the lower one. They wrote about it to their Bishop.

Using modern computer trace-backs of the moon’s motions and phases, we know have a prettty good idea that they saw a meteor hitting the moon and sending dust high into the sunlight at the dark edge of the moon, creating the "plume of light effect. And, just where that meteor was supposed to have hit, there is a fairly young crater that dates from about 1200 or so.

I find this such an charming and wonderful story that I would like to trace it. Also, could you tell me which crater that is and where to find it?

Damn, I was hoping someone else’d get into this. It’s been decades since I regularly aimed a scope at the moon.
Maupertuis is labeled (mouseover) on this map
Maupertuis is old, and very beat up. It probably looks jaggy at sunrise because other meteors have ripped up its rim.
Plato is about 3 billion years old, younger than Mare Imbrium; and yes, I just learned that Wikipedia has an extensive listing of lunar craters, and will go play with that some later. -You’re not getting expert knowledge here.

The explosion viewed by monks in 1178, supposedly produced the crater Giordano Bruno, 14km diameter, on the northeast limb, visible only during a favorable libration.
Unfortunately, there’s good reason to think that the witnesses did not see an impact of that magnitude.
Oh well, it was a nice story while it lasted.

The crater is Tycho very prominent at the bottom of the face of the moon with “rays” eminating from the point of impact. The story is rather well documented, so I will find you some links or references to support this - as it conflicts with a postr above. However, IIRC, Carl Sagan’s book “Cosmos” is one good source (and, I ain’t a Sagan fan). I shall return [with more info]! - Jinx