moon crater Maurolycus in lunar highlandsThe week of November 8-14 takes us from Day 5 to Day 11. This week we will highlight the moon crater Maurolycus and a feature informally referred to as “The Lunar X,” both viewable on Thursday evening, Day 8.

Maurolycus overlaps a smaller unnamed crater on its southern borderMaurolycus: [SE/P11; L=14°E] Let us venture briefly into a region where angels fear to tread, the lunar Highlands. Plunge in and look for the crater Maurolycus. Although the area looks confusing, Maurolycus will be the largest and most conspicuous crater in this sector. It is a breathtaking sight under an early morning Sun and should not be missed. Maurolycus displays a rich diversity of different types of features. How many can you see? The central mountain peaks are so tall that they are illuminated long before the Sun finds its way to the dark floor. Also notice how Maurolycus overlaps a smaller unnamed crater on its southern border. This flies in the face of the rule that says younger craters are usually smaller.

The Lunar XLunar X: [SE/M10; L=1°E] On Thursday evening, around 6 days 22 hours as the terminator crosses Blanchinus, the Sun will light up the mountain peaks immediately to the west of Blanchinus, and you will see a brilliantly lit “X” at the intersection of the rims of Blanchinus, La Caille, and Purbach. Look for it when the terminator is around 1°-2° east. Once it has formed, the image will last only for about three hours. The formation is also known as the Purbach Cross and the Werner X. (Because it is not an officially recognized object, you will not find it listed on the Field Map.)


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 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]

Courtesy of Gray Photography of Corpus Christi, Texas
Lunar photos: NASA / USGS / BMDO / LROC / ASU / DLR / LOLA / Moon Globe. Used by permission

Andrew Planck
The Lunar X and Moon Crater Maurolycus

Leave a Reply

Your email address will not be published. Required fields are marked *