"Dog Bone" Features In Cauchy & Fra Mauro
by Francis Ridge, Coordinator, The Lunascan Project

Lunascan Project image of "dog bone" & Plinius

Section 36 (part of which is shown above) is the central part of Mare Tranquilitatis. The most interesting area is in the neighborhood of the crater Cauchy (but not shown above), where under low illumination, a modest telescope will show rilles, a striking fault Rupes Cauchy and the typical domes Omega Cauchy and Tau Cauchy. On the summit of Omega Cauchy is a small craterlet, which is visible with a large telescope. A narrow cleft is present to the west of the crater Maskelyne. For a Lunascan tour of the Section 36, click here.

But one of the most interesting features has been neglected. I discovered this while imaging the Moon with the Lunascan Project's original telescope a few years ago. I was using the old 16" f/4.5 and while imaging around the Apollo 11 landing site I noticed a feature I described as a "dog bone". The image above is a frame-grab from that imaging session. This was originally thought to be the "dog bone" feature I found in an Apollo 16 image, but was not the case.

Recently, while researching AS16-120-19244 I found that Ranger 7 had impacted very close to the other "dog bone" featured in Section 42. See  Section 42.

Part of Rukl Chart 36                                     Part of Rukl Chart 42

Relative sizes of the two features can be seen in these portions of the Rukl charts  which are the same scale. Jansen Y in upper left of chart 36 is about 24 km wide. Note the proximity pf the Ranger 7 impact point just south of the the "dog bone" in Section 42 and the Apollo image mentioned above. A search through the Lunar Orbiter database  for a nearby crater (Darney) turned up an image of the feature, although very small. A cropped enlargement can be found below:

To see the full LO image image, click here, then even larger by clicking thumbnail image on page

If we get any other information or images we we will update this page.

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