Bob Moler's Ephemeris Blog

This is Ephemeris for Friday, March 11th. Today the Sun will be up for 11 hours and 41 minutes, setting at 6:43, and it will rise tomorrow at 7:00. The Moon, 1 day past first quarter, will set at 4:18 tomorrow morning.

As the Moon moves around the Earth, now one day past first quarter, more of it is revealed in sunlight. The top or north part of the moon is of interest now. The second-largest lunar sea, Mare Imbrium, or Sea of Showers, is now half illuminated by the advancing terminator, the sunrise line. That can be seen with the naked eye. With binoculars, in the mountains north or above Imbrium can be found the flat floored crater or walled plain called Plato. This crater is situated in the lunar Alps. Mountains on the Moon are named after their earthly counterparts. Visible in telescopes now will be the Alpine Valley cutting through the Alps just to the right of Plato. Each night from new to full, more of the Moon’s features are revealed near the terminator.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

The Moon tonight, a day past first quarter, March 11, 2022, outlining the Mare Imbrium, crater Plato area, which is seen in detail below. Created using Virtual Lunar Atlas.

The Moon tonight, March 11, 2022, highlighting the crater Plato and lunar Alps. The Alpine Valley (Vallis Alpes), lies under the caption “Alpes” for the mountains. One of cool things to watch when the terminator is situated just right is to watch the shadows of the mountains retreat across Plato’s crater floor as the Sun rises. The shadows of the peaks appear very jagged as they retreat. Created using Virtual Lunar Atlas.