Archive for August 4, 2014

08/04/2014 – Ephemeris – The Moon’s remarkable crater Clavius

August 4, 2014 Comments off

Ephemeris for Monday, August 4th.  The sun rises at 6:32.  It’ll be up for 14 hours and 31 minutes, setting at 9:03.   The moon, 1 day past first quarter, will set at 1:20 tomorrow morning.

Let’s take a look at the Moon tonight.  The south end of the moon is bright part, the lunar highlands, the oldest terrain on the Moon.  A huge crater is visible that just came into sunlight.  It is the crater Clavius.  It’s visible in binoculars, but it is best seen in a telescope with enough magnification so the moon more than fills the field of view.  Clavius has four small craters on its floor in a slight arc, in descending order of size.  Clavius itself is 136 miles (225 km) in diameter.  It has a flat floor, but it’s large enough to be convex following the curvature of the Moon, a fact that can be seen when Clavius is close to the terminator as it will be tonight.  It is another one of my favorite lunar features.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.


Moon tonight

The Moon highlighting the craters Clavius and Tycho for 10 p.m. August 4, 2014. Created using Virtual Moon Atlas.

A note:  For science fiction fans in the book and movie 2001 a Space Odyssey by Arthur C. Clarke the U.S. Moon Base was located in the crater Clavius, and the lunar monolith, designated TMA-1 (Tycho Magnetic Anomaly 1) in surveys, was located in the nearby crater Tycho.


Clavius as photographed by one of the Lunar Orbiter spacecraft in the 1960s. From Digital Lunar Orbital Photographic Atlas. Credit Jeff Gillis, Lunar and Planetary Institute.