Earth and Space News: Richardson Crater Parents Two Satellites on Lunar Far Side

Summary: Richardson Crater parents two satellites on the lunar far side, in the crater-jumbled area northeast of Mare Marginis (Sea of the Edge).

Detail of oblique, northwestward view, obtained February 1971 with 70mm Hasselblad camera during Apollo 14 mission shows Maxwell Crater (center left) nestled on Richardson Crater (center) with Richardson E (center right) and Richardson W (upper center); NASA ID AS14-71-9852: James Stuby (Jstuby), Public Domain (CC0 1.0), via Wikimedia Commons

Richardson Crater parents two satellites on the lunar far side, in the northwest quadrant's crater-jumbled area northeast of Mare Marginis (Sea of the Edge).

Primary lunar impact crater Richardson is centered at 30.93 degrees south latitude, 99.89 degrees east longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. Its northernmost and southernmost latitudes reach 33.63 degrees north and 28.27 degrees north, respectively. Its easternmost and westernmost longitudes extend to 103.06 degrees east and 96.8 degrees east, respectively. Richardson’s diameter measures 162.56 kilometers.

Richardson Crater serves as the parental crater in the Richardson Crater system. The large crater parents two satellites, Richardson E and Richardson W.

Richardson E is found near its parent’s eastern rim. The eastern satellite is centered at 32.01 degrees south latitude, 103.61 degrees east longitude. Its northernmost and southernmost latitudes occur at 32.36 degrees north and 31.65 degrees north, respectively. It registers easternmost and westernmost longitudes at 104.08 degrees east and 103.14 degrees east, respectively. Richardson E has a diameter of 24.14 kilometers.

Richardson E hunkers in proximity to the southwestern rim of its eastern neighbor, Szilard Crater. Primary lunar impact crater Szilard is centered at 33.71 degrees south latitude, 105.78 degrees east longitude. Szilard marks northernmost and southernmost latitudes at 35.8 degrees north and 31.61 degrees north, respectively. It obtains easternmost and westernmost longitudes at 108.3 degrees east and 103.26 degrees east, respectively. Szilard Crater’s diameter spans 127.22 kilometers.

Richardson W adjoins its parent’s northwestern rim. The western satellite is centered at 33.59 degrees south latitude, 98.34 degrees east longitude. It registers northernmost and southernmost latitudes at 33.98 degrees north and 33.21 degrees north, respectively. It records easternmost and westernmost longitudes at 98.8 degrees east and 97.88 degrees east, respectively. Richardson W’s diameter of 23.35 kilometers qualifies it as the smaller of its parent’s two satellites.

Richardson W’s nearest named primary craterous neighbors are Maxwell and Vestine. Maxwell lies to the south of satellite W. Vestine is sited to the west of Richardson W.

Maxwell Crater substantially overlies the southwestern portion of Richardson W’s parent. Maxwell is centered at 29.9 degrees north latitude, 98.53 east longitude. Maxwell Crater posts northernmost and southernmost latitudes of 31.71 degrees north and 28.1 degrees north, respectively. Its easternmost and westernmost longitudes occur at 100.6 degrees east and 96.45 degrees east, respectively. Maxwell Crater has a diameter of 109.24 kilometers.

Vestine Crater is centered at 33.87 degrees south latitude, 93.68 degrees east longitude. Vestine’s northernmost and southernmost latitudes extend to 35.48 degrees north and 32.26 degrees north, respectively. Its easternmost and westernmost longitudes reach 95.62 degrees east and 91.74 degrees east, respectively. Vestine Crater’s diameter measures 97.81 kilometers.

Swedish astronomer Leif Erland Andersson (Nov. 4, 1943-May 4, 1979) and British-born astronomer Ewen Adair Whitaker (June 22, 1922-Oct. 11, 2016) explained the assignment of far side satellite crater designations in their 1982 publication, NASA Catalogue of Lunar Nomenclature. “The letter designation scheme for the farside was devised for maximum ease in locating craters on maps, and works as follows: each ‘patronymic’ crater is considered to be the center of a 24 hour clockface in which the numbers have been replaced with Roman capital letters (I and O omitted, 24 h. = Z), with Z at the north point,” Andersson and Whitaker stated (page 6).

According to the 24-hour clockface of Roman capital letters, Z claims the position of 12 at the clockface’s top. A clockwise circuit finds B in the position of 1; D at 2; F at 3, H at 4; K at 5. M claims the bottom of the clockface, opposite 12, in the position of 6. P occupies 7’s spot; R is at 8. In the position of number 9 opposes F in number 3’s slot. V is at 10; X is at 11.

Andersson and Whitaker revealed the astronomy behind the clockface’s letter designations. “Thus each letter represents a fixed azimuth from the patronymic crater, and the chosen subsidiary craters are lettered according to their closest azimuths.”

The azimuth signifies the angle between a celestial body, such as the moon, and north, according to a clockwise measurement around the observer’s horizon. Richardson E’s designation indicates the satellite’s east-northeasterly position in the Richardson Crater system. Richardson W’s designation reveals the satellite’s northwesterly position in the Richardson Crater system.

The takeaways for Richardson Crater’s parentage of two satellites in the lunar far side are that Richardson E and Richardson W are positioned, respectively, to their parent’s east and northwest; that satellite E occupies a close location between its parent and eastern neighbor Szilard; and that satellite W intrudes into its parent’s northwestern rim.

Detail of Shaded Relief and Color-Coded Topography Map shows lunar far side’s Richardson Crater (upper right), with unmarked Richardson E (upper right) and W (upper center), to the northeast of Mare Marginis in the northwestern quadrant: U.S. Geological Survey, Public Domain, via USGS Astrogeology Science Center / Gazetteer of Planetary Nomenclature

Acknowledgment

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

Image credits:

Andersson, Leif E.; and Ewen A. Whitaker. NASA Catalogue of Lunar Nomenclature. NASA Reference Publication 1097. Washington DC: NASA National Aeronautics and Space Administration Scientific and Technical Information Branch, October 1982.
Available via NASA NTRS (NASA Technical Reports Server) @ https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19830003761.pdf

Consolmagno, Guy; and Dan M. Davis. Turn Left at Orion. Fourth edition. Cambridge UK; New York NY: Cambridge University Press, 2011.

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International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Mare Marginis.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/3681

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Richardson.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/5027

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Richardson E.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/12601

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Richardson W.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/12602

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Szilard.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/5799

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Target: The Moon.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon.
Available @ https://planetarynames.wr.usgs.gov/Page/MOON/target

International Astronomical Union (IAU) / U.S. Geological Survey (USGS) Gazetteer of Planetary Nomenclature. “Vestine.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature > Nomenclature > The Moon. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/6369

Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.

Marriner, Derdriu. "Richardson Crater Honors British Physicist Sir Owen Willans Richardson." Earth and Space News. Wednesday, April 11, 2012.
Available @ https://earth-and-space-news.blogspot.com/2012/04/richardson-crater-honors-british.html

The Moon Wiki. “IAU Directions.” The Moon.
Available @ https://the-moon.us/wiki/IAU_directions

The Moon Wiki. “Richardson.” The Moon > Lunar Features Alphabetically > R Nomenclature.
Available @ https://the-moon.us/wiki/Richardson

Moore, Patrick, Sir. Philip’s Atlas of the Universe. Revised edition. London UK: Philip’s, 2005.

Earth and Space News

Wednesday, April 18, 2012

Richardson Crater Parents Two Satellites on Lunar Far Side

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