I wanted to share an analysis that I did on some images taken on July 20, 2018. The moon was not very high in the sky at this time of year, but the libration was near maximum for observing the Southeastern limb and polar region, with a sub-Earth point of -6.8S, 7.5E. This allowed me to see farther South and farther East than I ever had before in this region. These occasions are few and far between (when factoring in weather, etc), so I am unsure when I will ever get the same view again.
I will post two annotated images that I took with my C9.25 Edge HD telescope, followed by two 3D views generated using LRO data that give a more overhead view of the area with some of the features seen in my images. Finally, I will post an image of the entire moon at this phase, and will provide a link for the full resolution image. The annotated images below are of decent quality, although the necessary compression may have caused some minor degradation, so you can always go to the full resolution image if you want another look, although that image is not annotated and is in a different orientation.
Following is my brief summary of the highlights of the images:
Image 1-
The crater Shackleton, containing the South Pole, is visible. Numerous craters are visible in the polar region that are typically difficult to see, including Amundsen, Hedervari, Idel'son, Idel'son L, and Ganswindt. On the left side of the image is the crater Hale, which shows good interior detail, despite being centered at 91.7E longitude. Beyond Hale, on the extreme limb, is the crater Rittenhouse (-74.2S, 107.1E), which is entirely on the far side (depending on how we define "far side"). Ganswindt, Idel'son and Idel'son L are also located entirely on the far side of the 90E longitude line. The extreme limb beyond Ganswindt and Idel'son forms the outer rim of the Schrodinger basin. There are numerous peaks visible on the horizon, and at first I thought some could be central peaks within Schrodinger itself, but after doing extensive analysis of LRO images and 3d models, I'm nearly certain that everything visible is merely on the rim. One would need additional help to see inside Schrodinger. It is tantalizingly close, however. Beyond Shackleton and Idel'son L, there is a ridge that I identified near the far side crater Wiechert. I put a label on Wiechert, but this is probably not 100% certain as it gets very tricky to identify features that far out. However, I think the placement is very close. This crater lies about 175km to the north of Shackleton on the far side.
Image 2-
This image picks up where the first one left off to the Southeast, with craters Hale and Rittenhouse on the right side. The region along the limb is notable because it is in the general vicinity of Vallis Schrodinger, which is a striking valley oriented radially to the Schrodinger basin. Like in the previous image, there are several identifiable craters that lie completely on the far side of the 90E longitude line, including Chamberlain, Chamberlain H, Moulton, Wexler E, Wexler H, and Rittenhouse. Although identification is not easy in these locations, thanks to interactive LRO maps that let you change the angle I feel fairly confident about the IDs. The are several peaks on the horizon, beyond Chamberlain, one of which I tentatively mapped to the approximate coordinates of -57.7S, 108.1E, which is on the rim of the crater Priestley, although there are several other possible peaks in the area so this ID is not 100% certain.
Interestingly, I'm fairly certain I am able to detect some features of Vallis Schrodinger, and I noted these on the image. The valley runs directly through the crater Sikorsky, which is slightly Northeast of the crater Wexler E, and would be on the extreme limb in this image. The bright albedo feature that I indicated appears to be an unnamed crater on the eastern rim of Sikorsky. The floor of Sikorsky is slightly below this level and therefore shielded from our view. Slightly to the left of this region, I indicated what I think is a region of the actual Vallis Schrodinger that is just barely detectable. One would never be able to assign this ID just from this image of course, but when looking at LRO data the features do seem to match up very closely.
Of course I was interested to see how these views compare to others taken from Earth. One difficultly is that most images are not labeled or described completely, and so Google searching for many of these craters does not give any amateur images. However, as the South Pole is a popular region to image, I was able to find multiple examples of images showing this same region under strong libration, and even some that include the crater Rittenhouse (although it was never labeled as such). However, the region on the Southeastern limb near Vallis Schrodinger is not a particularly popular location for most imagers, and so I did not find any images that show quite the view that is seen above. So if anyone knows of some comparable images of the region taken from Earth, I would appreciate any information to that end. Thanks, and of course any comments are welcome.
Image 1- South Polar Region
