I was imaging the Moon on 28th December, when I noticed a very distinct X at the edge of one of the craters in an area on the terminator. This is pareidolia, where the human eye sees familiar shapes from patterns, where they are not really there. I thought to myself, ah ha, the famous X! But as it turns out there is another X on a much larger scale that is quite famous and it is formed when portions of the rims of craters La Caille (68km wide), Blanchinus (68km) and Purbach (118km) catch the Sun’s light as the lunar dawn approaches. This is not that one!

I could find no reference to this one, although I am sure it has been seen before. 

The main image has the full field of view of the Player One Saturn-M SQR camera, when used with the Tele Vue 2X Barlow and my C14. It will therefore, through the Lucky Imaging process, give a resolution down to 500 metres. I restricted each video file to 10GB and with the usb 3 transfer rates was able to capture the video in ~ 30 secs. A lot of data in a very short time. It is a colour image and I encourage you to observe the variety of hues across the image. This is a north up RGB only image. I did not use a IR 642nm BP image as Luminance as I sometimes do. Version B, accessible via the mouse over has a more detailed insert of the region in question. It is not simply a blow up of the original image. After the first capture, I created a much smaller Region of Interest (ROI) around the X and made futher RGB and IR captures which I processed separately. 

The two significant craters at the top are Hercules at left and Atlas at right. The latter is remarkable for the array of rilles on its floor, which were created by vulcanism. This is undoubtedly older than Hercules as the floor was substantially flooded, almost filled, by lava. The impactor likely punched into the thin crust of the Moon and lava then flowed in. Hercules on the other hand is, I presume, younger. Here the impactor struck a thicker crust as the Moon had cooled since the Atlas impact. The lava looks like it still flowed in, but to a much lower level. See Revision C for an LRO map showing these craters. It also shows a nice rille in Lacus Somnorium at the bottom of the image, which can be seen in my image at lower right.
There is a submerged crater between them, Atlas E, which is no doubt even older. The distinct crater to its north is Keldysh and it can be seen in the LRO image (Revision D) along with Atlas E.
Revision E, again an LRO image, shows the location of the X. It is between craters Mason and Plana, the latter of which is almost entirely in shadow in my image. The famous crater Burg is to the upper left of the X and is again deep in shadow.

Do you not agree the Moon is a most fascinating place.

Happy New Year to you all and many thanks for both your apprecaition of my images through 2022, but also for the great pleasure in enjoying yours.