The week of April 10-16 takes us from Day 20 to Day 26. This week we will highlight moon craters in the Fra Mauro region, located in the SW quadrant of the Field Map at K8, and viewable early Thursday morning.

Fra Mauro on the moonFra Mauro region: [SW/K8; L=17°W] Moon craters in the Fra Mauro region are critical to understanding an important process that shaped the Moon. For this reason, the Apollo 14 astronauts, Alan Shepard and Ed Mitchell, landed just 20 miles north of Fra Mauro. Look closely at Fra Mauro and the three craters to its south–Parry, Guericke, and Bonpland. Look for the telltale gaps and gouges that cut through their rims and point significantly back to Mare Imbrium, their place of origin. This is classic Imbrium sculpturing and is a textbook example of how you can “read” the lunar surface. Can you see the north-south linear features on Fra Mauro, Bonpland, and Parry? There is one long rille that breaches the walls of all three craters. What does this tell you about the age of these craters as they relate to Mare Imbrium? In many craters such as Alphonsus (Day 7; L9), Pitatus (Day 8; M8), and Posidonius (Day 5; F12) the rilles are clearly contained within the outer protective rims of the mountains, suggesting that they are related to the formation of the crater itself.


On Saturday the Moon is at perigee and Saturn will be 3° north of the Moon.

1 T= longitude of terminator


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
Craters in the Fra Mauro Region: Critical to Understanding an Important Process that Shaped the Moon

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