Waxing Crescent Wednesday, Oct. 21, Shows Apollo 17’s Mare Serenitatis

Summary: The moon’s waxing crescent Wednesday, Oct. 21, shows Apollo 17’s Mare Serenitatis Basin emerging northeast of the terminator’s dark curve.

Photo shows approximately one-half of the moon’s far side (right of dotted line), which is not visible from Earth, and approximately one-half of the moon’s near side (left of dotted line), with arrowed caption indicating the sites of the Apollo program’s first and last manned lunar landings, Apollo 11 and Apollo 17, respectively; view of moon, taken from a distance of 16,000 kilometers (10,000 miles) after Apollo 11 crew fired their engines over the moon’s far side for placement in the correct trajectory for return to Earth: Courtesy NASA Marshall Space Flight Center History Office

The moon’s waxing crescent Wednesday, Oct. 21, shows Apollo 17’s Mare Serenitatis Basin emerging northeast of the terminator, the dramatic line that separates the lunar near side’s darkened and sunlit portions during the eight-phase lunar cycle’s six partially illuminated phases.

The waxing crescent is a transitional phase between the lunar cycle’s first primary phase of new moon and the cycle’s second primary phase of first quarter moon. October’s new moon takes place Friday, Oct. 16, at 19:31 Greenwich Mean Time/Coordinated Universal Time 3:31 p.m. Eastern Daylight Time), according to retired NASA astrophysicist Fred Espenak’s AstroPixels website.

The waxing crescent’s sliver skimpily hugs the near side’s leading, or eastern, limb, on Sunday, Oct. 18. The crescent progressively thickens to reach almost one-fifth surface illumination, at 0.24 coverage, on Wednesday, Oct. 21, according to the U.S. Naval Observatory’s Astronomical Applications website.

Illumination of one-third of the lunar surface, at 0.34 coverage, on Thursday, Oct. 22, signals the approach of the first quarter moon. Also known as a half moon, the first quarter moon shines with 50 percent surface illumination. October’s first quarter moon takes effect Friday, Oct. 23, at 13:23 UTC (9:23 p.m. EDT).

The National Aeronautics and Space Administration’s (NASA) Apollo 17 mission safely landed Commander Eugene Andrew Cernan (March 14, 1934-Jan. 16, 2017) and Lunar Module Pilot Harrison Hagan “Jack” Schmitt (born July 3, 1935) as the 11th and 12th humans to set foot on the moon. Apollo Lunar Module Challenger touched down Monday, Dec. 11, 1972, at 19:54:57 UTC (2:54 p.m. Eastern Standard Time) on the southeastern rim of Mare Serenitatis.

Mare Serenitatis is centered at 27.29 degrees north latitude and 18.36 degrees east longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. As a northern hemisphere mare, its northernmost and southernmost latitudes extend to 37.81 degrees north and 16.13 degrees north, respectively. The eastern hemisphere mare's easternmost and westernmost longitudes reach to 29.92 degrees east and 6.59 degrees east, respectively. Mare Serenitatis presents a diameter of 674.28 kilometers.

Italian Jesuit astronomers Francesco Maria Grimaldi (April 2, 1618-Dec. 28, 1663) and Giovanni Battista Riccioli (April 17, 1598-June 25, 1671) named the dark, rounded, basaltic lava plain in 1651. Mare Serenitatis (Sea of Serenity) appeared in a lunar map in their two-volume, encyclopedia reference work on astronomy, Almagestum Novum (New Almagest).

The Challenger landed in Taurus-Littrow Valley, a narrow valley in the southwestern Taurus Mountains. The three most prominent mountains around Apollo 17’s landing site are the range’s South Massif, North Massif and East Massif, according to the Universities Space Research Association’s (USRA) Lunar and Planetary Institute (LPI).

The Taurus-Littrow region of mountainous highlands and lowlands valley wedges between Mare Serenitatis and the Sea of Serenity’s southeastern neighbor, Mare Tranquillitatis (Sea of Tranquility). Northern Hemisphere moonwatchers know Mare Tranquillitatis as the dark lava plain that represents the Man in the Moon’s left eye. The Apollo program’s first manned lunar landing mission, Apollo 11, landed in southwestern Mare Tranquillitatis.

The Taurus-Littrow Valley is centered at 20.07 degrees north latitude, 30.79 degrees east longitude. The northern hemisphere valley’s northernmost and southernmost latitudes extend to 20.34 degrees north and 19.75 degrees north, respectively. As an eastern hemisphere valley, its easternmost and westernmost longitudes reach to 31.13 degrees east and 30.42 degrees east, respectively. The valley’s diameter spans 21.03 kilometers.

The Challenger’s landing site lies south of Littrow Crater, according to the Lunar and Planetary Institute. The eroded, worn crater is centered at 21.5 degrees north latitude, 31.39 degrees east longitude. As a northern hemisphere crater, its northernmost and southernmost latitudes reach to 21.97 degrees north and 21.03 degrees north, respectively. The eastern hemisphere crater’s easternmost and westernmost longitudes extend to 31.9 degrees east and 30.89 degrees east, respectively. Littrow Crater’s diameter measures 28.52 kilometers. Approved by the International Astronomical Union (IAU) in 1935, the crater’s name honors Bohemian Austrian astronomer Joseph Johann von Littrow (March 13, 1781-Nov. 30. 1840).

Apollo 17’s lunar landing site is located about 7 kilometers east of Shorty Crater, according to the Dec. 12, 2011, post for NASA/Arizona State University’s (ASU) Lunar Reconnaissance Orbiter Camera (LROC) website by Dr. Mark S. Robinson, LROC’s principal investigator (PI). Harrison Schmitt discovered orange soil near the crater’s south rim crest during Cernan and his second extravehicular activity (EVA), which began Dec. 12, at 23:54 GMT/UTC (6:54 p.m. EST).

Shorty Crater is centered at 20.22 degrees north latitude, 30.63 degrees east longitude. The eastern hemisphere crater registers easternmost and westernmost longitudes of 30.63 degrees east and 30.62 degrees east, respectively. The crater’s diameter spans 0.11 kilometers.

Harrison Schmitt is credited with naming the crater, according to American astronomer and Apollo Lunar Surface Journal founder Eric M. Jones. Schmitt named the crater after the character of Shorty in Trout Fishing in America, published in 1967 by American novelist and short story writer Richard Brautigan (Jan. 30, 1935-ca. Sept. 16, 1984) and also as a tribute to the short story genre from American writer J.D. (Jerome David) Salinger (Jan. 1, 1919-Jan. 27, 2010) forward. The IAU approved the name in 1973.

The takeaway for the waxing crescent’s Oct. 21 showing of Apollo 17’s Mare Serenitatis is that the 11th and 12th humans (and, thus far, the last two) to walk on the moon landed in the highland-lowland wedge between Mare Serenitatis and the Man in the Moon’s left eye, Mare Tranquillitatis.

Image, captured by NASA’s Lunar Reconnaissance Orbiter Camera’s (LROC) Narrow Angle Cameras (NAC) show Apollo 17’s landing site in the Taurus-Littrow Valley of southeastern Mare Serenitatis; ALSEP=Apollo Lunar Surface Experiments Package; LRV=Lunar Roving Vehicle; MESA=Modularized Equipment Stowage Assembly; PLSS=Portable Life Support System; SEP=Surface Electrical Properties experiment; image released Sep. 5, 2011: NASA/Goddard/ASU, via NASA LRO Mission

Acknowledgment

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

Image credits:

Photo shows approximately one-half of the moon’s far side (right of dotted line), which is not visible from Earth, and approximately one-half of the moon’s near side (left of dotted line), with arrowed caption indicating the sites of the Apollo program’s first and last manned lunar landings, Apollo 11 and Apollo 17, respectively; view of moon, taken from a distance of 16,000 kilometers (10,000 miles) after Apollo 11 crew fired their engines over the moon’s far side for placement in the correct trajectory for return to Earth: Courtesy NASA Marshall Space Flight Center History Office @ https://history.msfc.nasa.gov/saturn_apollo/photos/apollo17_006.html

Image, captured by NASA’s Lunar Reconnaissance Orbiter Camera’s (LROC) Narrow Angle Cameras (NAC) show Apollo 17’s landing site in the Taurus-Littrow Valley of southeastern Mare Serenitatis; ALSEP=Apollo Lunar Surface Experiments Package; LRV=Lunar Roving Vehicle; MESA=Modularized Equipment Stowage Assembly; PLSS=Portable Life Support System; SEP=Surface Electrical Properties experiment; image released Sep. 5, 2011: NASA/Goddard/ASU, via NASA LRO Mission @ https://www.nasa.gov/mission_pages/LRO/news/lro-briefing-20110906.html

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