Vitello – a strange crater on the moon

Vitello drawn by Harry Roberts

If you have a small telescope or a friend with one that you can use, it is worth while examining the moon. Huge amount of details are visible and the features change in appearance as the lunar day progresses. Most detail is visible when the moon is at first (or last) quarter as that is when the Sun is just rising (or setting) in the areas at the centre of the visible disc and is casting deep shadows.

Amateur astronomer and member of the Sydney City Skywatchers Harry Roberts does exquisitely detailed drawings of the moon. Here is his drawing and description of a crater named Vitello:

Scattered around the “shoreline” of Mare Humorum are several unusual lunar craters. The most conspicuous is gigantic Gassendi to the north, and opposite it on the southern “shore’ is Doppelmayer, looking like a half size copy of Gassendi. Both are shallow craters with a central mountain range and a network of rilles and ridges on their floors. Both give the impression that their floors are convex. Close to Doppelmayer we find Vitello, looking like a quarter size version of Gassendi, a family of crater “clones”!

Vitello’s most eye-catching feature is a near circular bright rille that encloses the brilliant chain of central peaks. I have oriented the sketch to give an astronauts-eye view into the crater from overhead. Vitello has the looks of a crater three times its size, but in fact is only 42 km across. The bright rille arises at a small crater or vent just inside the northern rim, and after meandering south for 10km sweeps around the crater floor in a near perfect curve to terminate near the central peaks.

Wood tells us that these flat-floored craters surrounding Humorum are floor-fractured craters (FFC’s, Charles Wood “Modern Moon etc.” p85). He suggests such craters have been uplifted by lava from below.

Vitello was Erazmus Witelo, 1225 – 1290, a Polish mathematician and physicist who worked in Padua, Italy. The Moon is covered with craters of all kinds, and Vitello is one of the stranger ones. Take a close look at Mare Humorum, and see the shallow fractured floor craters that surround it. It’s an extraordinary sight.

Enjoy moon watching.

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