First Quarter Friday, Oct. 23, Shows Apollo 16’s Descartes Highlands

Summary: The moon’s first quarter Friday, Oct. 23, shows Apollo 16’s Descartes Highlands as a rugged jumble west of the lunar near side’s Mare Nectaris.

artist’s concept of eastward view of Apollo 16’s Descartes landing site shows Apollo 16 astronauts’ scheduled transverses (white overlay) in the Lunar Roving Vehicle (LRV); Roman numerals for extravehicular activities (EVAs) and Arabic numbers for traverse station stops; illustration by NASA graphic artist Jerry Elmore; NASA ID S72-16940: Public Domain, via NASA NTRS (NASA Technical Reports Server)

The moon’s first quarter Friday, Oct. 23, shows Apollo 16’s Descartes Highlands as a rugged jumble in the south central lunar highlands west of Mare Nectaris, occupying the leading, or right, half of the moon’s near side for Northern Hemisphere moonwatchers.

October’s first quarter phase begins Friday, Oct. 23, at 13:23 Greenwich Mean Time/Coordinated Universal Time (9:23 a.m. Eastern Daylight Time), according to retired NASA astrophysicist Fred Espenak’s AstroPixels website. As the second of four primary phases in the eight-phase lunar cycle, the first quarter phase signifies illumination of half of the lunar near side’s surface, from Earth’s perspective.

The National Aeronautics and Space Administration’s (NASA) Apollo 16 mission safely landed Commander John Watts Young (Sept. 24, 1930-Jan. 5, 2018) and Lunar Module Pilot Charles “Charlie” Moss Duke Jr. (born Oct. 3, 1935) as the ninth and 10th humans to set foot on the moon. Apollo Lunar Module Orion touched down Friday, April 21, 1972, at 02:23:35 Universal Time (Thursday, April 20, at 9:23 p.m. EST), in the Descartes Highlands’ Cayley Plains. Lunar Module Orion settled between “two fresh, young impact craters,” North Ray and South Ray craters, according to the Universities Space Research Association’s (USRA) Lunar and Planetary Institute (LPI).

North Ray Crater is centered at minus 8.82 degrees south latitude, 15.48 degrees east longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. The southern hemisphere crater's northernmost and southernmost latitudes extend to minus 8.8 degrees south and minus 8.83 degrees south, respectively. As an eastern hemisphere crater, its easternmost and westernmost longitudes reach to 15.5 degrees and 15.47 degrees, respectively. The sharp-rimmed crater’s diameter measures 0.95 kilometers.

South Ray Crater is centered at minus 9.15 degrees south latitude, 15.38 degrees east longitude. As a southern hemisphere crater, its northernmost and southernmost latitudes reach to minus 9.14 degrees south and minus 9.16 degrees south, respectively. As an eastern hemisphere crater, is easternmost and westernmost longitudes extend to 15.39 degrees east and 15.37 degrees east, respectively. The bright-rayed crater has a diameter of 0.7 kilometers.

The two craters framing Orion’s landing site are located on the Cayley Plains. To the east and south of Orion’s touchdown, the jumbled uplands of the Descartes Mountains contrast with the fairly level plains.

The Cayley Plains take their name from Cayley Crater. The small, circular, bowl-shaped crater is centered at 3.94 degrees north latitude, 15.09 degrees east longitude. As a northern hemisphere crater, its northernmost and southernmost latitudes extend to 4.17 degrees north and 3.7 degrees north, respectively. As an eastern hemisphere crater, its easternmost and westernmost longitudes reach to 15.32 degrees east and 14.85 degrees east, respectively. Cayley Crater’s diameter measures 14.2 kilometers. In 1935, the International Astronomical Union approved the crater’s name, which honors British mathematician Arthur Cayley (Aug. 16, 1821-Jan. 26, 1895).

The Descartes Highlands take their name from Descartes Crater. The heavily degraded crater lies about 50 kilometers south of Apollo 16’s landing site. Descartes Crater is centered at minus 11.74 degrees south latitude, 15.67 degrees east longitude. As a southern hemisphere crater, its northernmost and southernmost latitudes reach minus 10.96 degrees south and minus 12.53 degrees south, respectively. As an eastern hemisphere crater, its easternmost and westernmost longitudes extend to 16.47 degrees east and 14.86 degrees east, respectively. The crater’s diameter measures 47.73 kilometers. In 1935, the International Astronomical Union approved the crater’s name, which honors French mathematician and philosopher René Descartes (March 31, 1596-Feb. 11, 1650).

Lunar Module Orion rests about 600 kilometers west of the center of the Nectaris Basin. Mare Nectaris (Sea of Nectar) occupies the basin’s central region. The small, round, dark lava plain is centered at minus 15.19 degrees south latitude, 34.6 degrees east longitude. The southern hemisphere mare’s northernmost and southernmost latitudes reach minus 9.9 degrees south and minus 21.05 degrees south, respectively. As an eastern hemisphere lava plain, its easternmost and westernmost longitudes stretch to 39.68 degrees east and 28.75 degrees east, respectively. Its diameter spans 339.39 kilometers.

The takeaway for the first quarter’s Oct. 23 showing of Apollo 16’s Descartes Highlands is that the ninth and 10th humans to walk on the moon landed in the fairly level Cayley Plains, north of Descartes Crater and west of Mare Nectaris.

Apollo 16 landing site map shows feature names and actual traverse routes; Lunar Module (LM) Orion (center right), North Ray Crater (top right), South Ray Crater(bottom center); hi-resolution scan by Mary Ann Hagar/LPI: NASA/Lunar and Planetary Institute, via NASA History Apollo 16 Image Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

artist’s concept of eastward view of Apollo 16’s Descartes landing site shows Apollo 16 astronauts’ scheduled transverses (white overlay) in the Lunar Roving Vehicle (LRV); Roman numerals for extravehicular activities (EVAs) and Arabic numbers for traverse station stops; illustration by NASA graphic artist Jerry Elmore; NASA ID S72-16940: Public Domain, via NASA NTRS (NASA Technical Reports Server) @ https://science.ksc.nasa.gov/mirrors/images/images/pao/AS16/10075787.jpg;
NASA Johnson Space Center Collection, via NASA Images @ https://nasaimages.lunaimaging.com/luna/servlet/detail/nasaNAS~7~7~34554~138421:Artist-s-concept-of-eastward-view-o;
via Apollo Explorer @ http://www.apolloexplorer.co.uk/default.asp?libsrc=/photo/html/AS16/10075787.htm

Apollo 16 landing site map shows feature names and actual traverse routes; Lunar Module (LM) Orion (center right), North Ray Crater (top right), South Ray Crater (bottom center); hi-resolution scan by Mary Ann Hagar/LPI: NASA/Lunar and Planetary Institute, via NASA History Apollo 16 Image Library @ https://history.nasa.gov/alsj/a16/a16psrf6-4.jpg

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