The week of June 28 – July 4 takes us from Lunar Day 19 to Day 24. This week we will highlight the craters Walther and Deslandres, viewable after midnight on Wednesday.

moon craters Walther and DeslandresWalther: [SW/N9] You will find this 87-mile crater adjoining Deslandres just to its east. Because it has some very complex ramparts, under a setting Sun (which is the case early Thursday morning), Walther is a strikingly beautiful object. It has an offset group of central mountains, which have been impacted by several small craters.

moon crater DeslandresDeslandres: [SW/N9] (day.LAHN.druh) This is a large 145-mile crater located just inland from the southeast shore of Mare Nubium which, in spite of its partially ruined state, displays a number of interesting features: craterlets, crater chains, and hills which must be viewed under a low-angle Sun. Notice how the crater Lexel, which has intruded on the southeast rim of Deslandres, seems to be a subsidence feature. Deslandres is in such a state of disrepair that it wasn’t even recognized as a crater until well into the 20th century. If you had just run across Deslandres for the first time, would you have trouble identifying it as a crater (particularly when the Sun is higher and there is less contrast)?


On June 30, 1908, a meteor, 330 feet in diameter, streaked across the sky above the Tunguska River in Siberia at an altitude of 3-6 miles above the Earth, and flattened an estimated 80 million trees. It is the largest impact event in recorded history and would have destroyed a large metropolitan area. Fortunately, because the area was so sparsely populated, only three people died.


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

Andrew Planck

Author and Astronomer Andrew Planck shepherds you to the moon and its mysteries of intrigue and surprise. Learn about the moon’s most fascinating objects, understand how the moon was formed and the names of many of the craters … and why they honor individuals who have changed the course of history.
Andrew Planck
Moon Crater Walther and Moon Crater Deslandres

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