The week of February 19-25 takes us from Day 11 to 16. This week we will highlight the moon crater Langrenus, viewable on Sunday night.

Langrenus moon craterLangrenus & Vendelinus: [SE/K-L16; L=61°E] These craters are the first two segments of the Great Eastern Chain. Langrenus and Vendelinus are two large 90-mi. craters located on the southeast shore of Fertility. One is considerably older than the other and appeared before the lava flows started. It should be easy for you to decide which is which.1

Vendelinus moon craterThe terraces and central peaks of Langrenus will have emerged from last night’s shadows, and tonight the crater is a beautiful sight. Even if you have a small telescope, there is much detail in the interior and on the outer ramparts to keep you busy. Because the appearance of the crater changes significantly with different lighting angles, make some drawings of what it looks like tonight and come back over the next few nights to compare the views.



Copernicus was born on Feb. 19, 1473.
John Glenn becomes the first U.S. astronaut to orbit the Earth on February 20, 1962.

1 The younger moon crater Lamé intrudes on Vendelinus on its NE rim, and it is appropriately smaller. However, notice that Lamé, in turn, overlaps two smaller unnamed craters on its S.W. rim. This is unusual in that intruding craters are almost always smaller than the craters they impact on.

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
Langrenus & Vendelinus Moon Craters: First Two Segments of Great Eastern Chain

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