L9: Clavius

Clavius is the third largest crater on the moon’s near side, and it can be found close to the southern limb. The crater is also one of the oldest, which is evident from the many smaller craters that mark the Clavius plain. At local sunrise the two larger of these — Clavius C and D — gives rise to a clair-obscur phenomena, giving the impression of two eyes staring back at you.

My observation of Clavius was done under a 10 days old moon, so I didn’t get to see the Eyes of Clavius (which only shows at 9 days). But the illumination nicely captured the dramatic landscape of the crater. When I started out the seeing was terrible, and I hesitated whether to continue or to call it a night. Eventually I decided to give it a shot, hoping that it might improve after a while. The turbulence settled somewhat as the moon rose, but it wasn’t enough to capture any finer detail.

Clavius C and D are the two largest craters just right of the center. The rim is marked by Porter (top right) and Rutherford (bottom right). The large adjacent crater towards the bottom left is Blacanus.

Sketch made 23 September 2015, UT 17:30, using a Celestron XLT 120 and a TeleVue Nagler zoom 3-6 mm. Seeing 1/5, gradually improving to 3/5. South is up.

Clavius have also made an imprint on popular culture: In Arthur C. Clarke’s 2001: Space Odyssey American activities on the moon are centered around a base build underneath the surface of the crater plain. When Dr Floyd sets out to investigate the monolith excavated in Tycho, he takes the moon shuttle from the Clavius Base.

Clavius Base. Screen capture from 2001: Space Odyssey.

Below is a clip from 2001: A Space Odyssey showing the encounter with the monolith found in Tycho crater. The soundtrack still gives me creeps.