2017, December 27: The Moon


The nearly 10-day-old waxing gibbous moon shines high in the southeast this evening. Mare Imbrium, a large impact feature that is now a filled with cooled volcanic material, is nearly in sunlight. Imbrium is over 700 miles in diameter, easily visible without a telescope. Copernicus, lies south of Imbrium, now has its lunar morning as it is near the terminator, the division between daylight and nighttime.

Eratosthenes appears to the upper right of Copernicus at the western edge of the Apennine Mountains that form the rim of the Imbrium region.

Tycho is now in full sun farther to the south.  Its rays make it look like a huge lunar bug.  These bright lines are from material that splattered across the surface when a large meteorite crashed into the moon.  The greyish splash is easier observed in a few nights as the moon’s phase continues to wax.

Clavius is below Tycho.

To the lower left of Tycho and along the terminator where the shadows are longer from the rising sun, Longomontanus is visible.  Immediately north of Longomontanus is a cluster of three overlapping craters; the obvious one in the image is Wilhem.

All of these features are visible in the lunar image when it is magnified on the computer screen.

Lunar observing is an easy and inexpensive way to get started in astronomy.  The binoculars that are used for bird watching and sporting events can be aimed at the moon to view its features.  The moon is easily found in the sky and can form the basis of a regular observing habit as the changing phase either reveals or hides features:  craters, mountains, plains, and valleys.  Certainly this is a way to introduce a child to astronomy.  The investment in a good binocular is relatively inexpensive.  If the interests wanes, then the binocular has other functions.

If you’re interested in exploring the lunar surface further, a  good resource is Exploring the Moon Through Binoculars by Ernest Cherrington.  The book is now out-of-print, but might be found on the resale market inexpensively.  The author wrote another lunar observing book with a similar title, Exploring the Moon Through Binoculars and Small Telescopes.  This can be found inexpensively and in electronic versions.

Happy lunar observing.

The articles that follow provide details about the planets visible without optical assistance (binoculars or telescope):



One comment

  1. Thank you, Jeffrey, for sharing your knowledge and wisdom in your wonderful blog! Happy New Year!

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