The week of May 19-25 takes us from Day 22 to Day 28. This week we will highlight the moon crater Copernicus, the Monarch of the Moon, visible on Tuesday night.
Copernicus: [NW/J7; L=20°W] Magnificent Copernicus has been justifiably dubbed “The Monarch of the Moon.” The moon crater was blasted out 800 million years ago in an explosion that was so powerful that some of the ejected debris almost certainly rained down on the Earth. It is 58 miles in diameter and has walls that rise to an impressive 12,400 ft. above the floor. As a result, sunrise over Copernicus at the beginning of Day 9 is a thing of beauty! This single moon crater is large enough to enclose the state of Rhode Island. In the center, there is a complex of mountains that is worth studying. Some authorities say there are up to seven peaks. How many can you count?
See if you can spot the tiny moon crater Copernicus A (2.2 miles in diameter) on the east wall under the high rim peak. (It will be about 2 arc-seconds in diameter, so 100x or more should do the trick.)
There is a complex system of ridges radiating from Copernicus, and on the surrounding terrain between Copernicus and Eratosthenes, you will find a host of secondary craters that resulted as huge boulders were blown out from the original impact and landed some distance away. These are some of the best secondaries on the Moon.
Immediately south of Copernicus is Fauth, a double moon crater that gives you the impression that you are peering at a keyhole.
OF ADDITIONAL INTEREST IN SPACE
On Thursday, Saturn will be 2.8° south of the Moon, and on Friday, Venus will be 4.0° south of the Moon.
======================
It is highly recommended that you get a copy of Sky and Telescope’s Field Map of the Moon, the very finest Moon map available for use at the telescope. It is available for $10.95 at www.skyandtelescope.com and on Amazon. All features mentioned in this blog will be keyed to the grid on the Field Map and will look like this: Plato: [NW/D9]
Credits:
Courtesy of Gray Photography of Corpus Christi, Texas
Lunar photos: NASA / USGS / BMDO / LROC / ASU / DLR / LOLA / Moon Globe. Used by permission
- Bailly – Largest Crater on Our Side of the Moon - January 12, 2026
- Longomontanus: Exception to the Rule About Moon Crater Age - January 5, 2026
- Schickard: Terrain Made Up of Two Different Chemical Compositions - December 29, 2025