First October 2020 Full Moon Shows Apollo 11’s Mare Tranquillitatis

Summary: The first October 2020 full moon shows Apollo 11’s Mare Tranquillitatis on Oct. 1, as the Man in the Moon’s left eye for Northern Hemisphere viewers.

NASA’s Lunar Reconnaissance Orbiter Camera (LROC) image Sept. 29, 2009, shows the Apollo 11 landing site (Eagle Descent Stage), along with Laser Ranging Retro-Reflector (LRRR) and Passive Seismic Experiment (PSE), west of Little West and West craters, on the flats of southwestern Mare Tranquillitatis: NASA/Goddard Space Flight Center/Arizona State University, via NASA

The first October 2020 full moon shows Apollo 11’s Mare Tranquilitatis on Thursday, Oct. 1, as the irregularly shaped, dark lava plain that Northern Hemisphere viewers identify as the Man in the Moon’s left eye.

The first of two full moons shining in October 2020 takes place Thursday, Oct. 1, at 21:05 Greenwich Mean Time/Coordinated Universal Time (5:05 p.m. Eastern Daylight Time), according to retired NASA astrophysicist Fred Espenak’s AstroPixels website. The month’s second full moon, known as a blue moon, happens Oct. 31, at 09:49 GMT/UTC (5:49 p.m. EDT).

At 100 percent lunar surface visibility, the full moon Thursday, Oct. 1, shows Apollo 11’s Mare Tranquillitatis as the middle of three dark, roughly circular shapes that slant downward below Mare Crisium (Sea of Crises). The oval, wringled-edged lava plain perches by itself near the moon’s leading limb. Mare Crisium is centered at 16.18 degrees north latitude, 59.1 degrees east longitude. Its diameter measures 555.92 kilometers.

The National Aeronautics and Space Administration’s (NASA) Apollo 11 mission safely landed American astronauts Neil Alden Armstrong (Aug. 5, 1930-Aug. 25, 2012) and Edwin “Buzz” Eugene Aldrin Jr. (born Jan. 20, 1930) as the first two people on Earth’s moon. The Apollo Lunar Module Eagle made the first manned landing July 20, 1969, at 20:17 UTC (4:17 p.m. EDT), in southwestern Mare Tranquillitatis.

Mare Tranquillitatis is an irregularly shaped, basaltic lava plain in the near side of the moon’s northeastern quadrant. Planetographic coordinates for Mare Tranquillitatis identify the lava plain’s center latitude at 8.35 degrees north and its center longitude at 30.83 degrees east, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. Its northernmost and southernmost latitudes reach to 19.37 degrees north and minus 4.05 degrees south, respectively. As an eastern hemisphere lava plain, its easternmost and westernmost longitudes extend to 45.49 degrees east and 16.92 degrees east, respectively.

With a diameter of 875.75 kilometers (544.16 miles), Mare Tranquillitatis lies in the Tranquillitatis Basin. The basin’s formation likely traces to a very large impact in the moon’s early prehistory, probably dating back more than 3.9 billion years, according to the Lunar Reconnaissance Orbiter mission pages on NASA’s website. Tranquillitatis Basin is centered on 0.68 degrees north latitude, 23.43 degrees south longitude. The basin’s northernmost and southernmost latitudes roughly extend from 20.4 degrees north to minus 4.4 degrees south. Its easternmost and westernmost longitudes roughly stretch from 45.9 degrees east to 15.0 degrees east.

Italian Jesuit astronomers Francesco Maria Grimaldi (April 2, 1618-Dec. 28, 1663) and Giovanni Battista Riccioli (April 17, 1598-June 25, 1671) are credited with naming Mare Tranquillitatis in 1651. The name appeared in a lunar map in their two-volume, encyclopedic reference work on astronomy, Almagestum Novum (New Almagest).

Mare Tranquillitatis translates as Sea of Tranquility, in American English. British English doubles the letter l for spelling as Sea of Tranquillity.

The Eagle landed approximately 400 meters (1,312 feet) west of West Crater, according to the Smithsonian’s National Air and Space Museum website. The sharp-rimmed, rayed crater is centered at 0.67 degrees north latitude, 23.49 degrees east longitude. West Crater’s diameter measures 0.19 kilometers.

The Apollo 11 landing site is proximitous to Little West Crater, according to NASA Goddard Space Flight Center and Arizona State University’s Lunar Reconnaissance Orbiter Camera (LROC) website. Little West Crater lies approximately 50 meters (164 feet) east of the landing site. The Gazetteer of Planetary Nomenclature gives center coordinates of 0.67 degrees north latitude and 23.48 degrees east longitude for Little West. The small crater’s diameter measures 0.04 kilometers.

At 20:17:58 UTC, approximately 18 seconds after the Eagle’s successful landing, Commander Armstrong referred to the landing site as Tranquility Base. In 1970, the International Astronomical Union, which serves as the international authority for planetary and satellite names, approved Statio Tranquillitatis (Tranquility Base) as the site’s official name. IAU naming conventions require that the dark patches, mistakenly perceived as seas by early astronomers, have names in Latin that describe weather and abstract concepts.

Statio Tranquillitatis has a center latitude of 0.67 degrees north. Its center longitude is 23.47 degrees east.

The takeaway for the first October 2020’s showing of Apollo 11’s Mare Tranquillitatis is that the first two humans to walk on the moon landed in southwestern Mare Tranquillitatis, the dark lava plain that represents the Man in the Moon’s left eye for Northern Hemisphere moonwatchers.

Apollo 11’s Mare Tranquillitatis (Sea of Tranquility) landing site lies in the lava plain’s southwestern flats; Mare Crisium (Sea of Crises) perches near the moon’s leading limb, above the southeasterly slanting trio of Mare Serenitatis (Sea of Serenity), Mare Tranquillitatis and Mare Fecunditatis (Sea of Fecundity); Friday, Oct. 22, 2010, 23:21, image of full moon photographed from Madison, north central Alabama, with Canon EOS Rebel T1i (EOS 500D) digital camera on Celestron 9.25 Schmidt-Cassegrain telescope: Soerfm, CC BY SA 3.0 Unported, via Wikimedia Commons

Acknowledgment

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

Image credits:

NASA’s Lunar Reconnaissance Orbiter Camera (LROC) image Sept. 29, 2009, shows the Apollo 11 landing site (Eagle Descent Stage), along with Laser Ranging Retro-Reflector (LRRR) and Passive Seismic Experiment (PSE), west of Little West and West craters, on the flats of southwestern Mare Tranquillitatis: NASA/Goddard Space Flight Center/Arizona State University, via NASA @ https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc_20090929_apollo11.html

Apollo 11’s Mare Tranquillitatis (Sea of Tranquility) landing site lies in the lava plain’s southwestern flats; Mare Crisium (Sea of Crises) perches near the moon’s leading limb, above the southeasterly slanting trio of Mare Serenitatis (Sea of Serenity), Mare Tranquillitatis and Mare Fecunditatis (Sea of Fecundity); Friday, Oct. 22, 2010, 23:21, image of full moon photographed from Madison, north central Alabama, with Canon EOS Rebel T1i (EOS 500D) digital camera on Celestron 9.25 Schmidt-Cassegrain telescope: Soerfm, CC BY SA 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Apollo-11-landing-site.png

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