Near Side Crater Celsius Honors Swedish Astronomer Anders Celsius

Summary: Near side Crater Celsius honors Swedish astronomer Anders Celsius, proposer of the Celsius scale and founder of Sweden's oldest observatory.

Crop of Lunar Orbiter 4 photograph, taken in 1967, shows Celsius Crater with interior satellite H (center; between 10 and 11); sun angle at 68.3 degrees, spacecraft altitude at 2973.34; D. Bowker and K. Hughes, Lunar Orbiter Photographic Atlas of the Moon (1971); 1967 Lunar Orbiter IV photograph IV-88-H3 Plate 420: National Aeronautics and Space Administration (NASA), Public Domain, via NASA NTRS (NASA Technical Reports Server)

Lunar near side Crater Celsius honors Swedish astronomer Anders Celsius, whose accomplishments include proposing the Celsius scale of temperature and founding Sweden's oldest observatory, known as Celsius Observatory.

Celsius Crater occupies the cratered terrain of the lunar near side's southeastern quadrant. The middle latitude crater resides in the central portion of the near side's southern hemisphere.

The small lunar impact crater presents a greatly worn outline. Numerous small crater impacts have damaged the crater's southwestern rim. Celsius Crater's satellite H gouges Celsius's pimpled, yet fairly level interior floor to the north of the crater's midpoint.

Celsius Crater is centered at minus 34.1 degrees south latitude, 20.05 degrees east longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. The southern hemisphere crater records northernmost and southernmost latitudes at minus 33.46 degrees south and minus 34.74 degrees south, respectively. The eastern hemisphere crater registers easternmost and westernmost longitudes at 20.82 degrees east and 19.27 degrees east, respectively. Near side circular lunar crater Celsius's diameter measures 38.96 kilometers.

The eastern hemisphere crater resides southwest of the eastern hemisphere's Mare Nectaris ("Sea of Nectar"). Mare Nectaris is centered at minus 15.19 degrees south latitude, 34.6 degrees east longitude. The lunar mare's northernmost and southernmost latitudes reach minus 9.9 degrees south and minus 21.06 degrees south, respectively. The dark, basaltic plain's easternmost and westernmost longitudes extend to 39.68 degrees east and 28.75 degrees east, respectively. Mare Nectaris has a diameter of 339.39 kilometers.

The eastern hemisphere crater lies southeast of the western hemisphere's Mare Nubium ("Sea of Clouds"). Mare Nubium is centered at minus 20.59 south latitude, minus 17.29 degrees west longitude. The western hemisphere lunar mare finds its northernmost and southernmost latitudes at minus 11.85 degrees south and minus 30.48 degrees south, respectively. The dark, basaltic plain's easternmost and westernmost longitudes occur at minus 5.45 degrees west and minus 29.27 degrees west, respectively. The Sea of Clouds measures 714.5 kilometers.

Celsius Crater forms a crater system with five craters. Satellite H lies on its parent's interior floor. Celsius A and Celsius E reside to their parent's north. Celsius B and Celsius D are positioned to the southwest of their parent.

The International Astronomical Union officially approved Celsius Crater’s name in 1935, during the organization’s Vth (5th) General Assembly, held from Wednesday, July 10, to Wednesday, July 17, in Paris, France. The designations of the Celsius Crater system's five satellites were approved in 2006. Lunar Crater Celsius honors early 18th-century Swedish astronomer Anders Celsius (Nov. 27, 1701-April 25, 1744).

In 1741 Anders Celsius established the first "real" astronomical observatory at his alma mater, eastern coastal Sweden's Uppsala University (Uppsala universitet), according to the website of Uppsala University's Department of Physics and Astronomy. In The Biographical Dictionary of Scientists: Astronomers (1984), science textbook author David Abbott describes the observatory as ". . . the first installation of its kind in Sweden" (page 35). The building, minus its observatory tower, still stands in Uppsala's center.

Anders Celsius proposed the Celsius scale of temperature in a paper presented in 1742 to the Swedish Academy of Sciences (Kungliga Svenska Vetenskapsakademiens). "Observationer om Twänne Beständiga Grader på en Thermometer" (Observations about two stable degrees on a thermometer) was published in the July August September 1742 issue of the Academy's Proceedings (Kungliga Svenska Vetenskapsakademiens Handlingar).

Celsius envisioned a fixed scale for scientific temperature measurements. He based the fixed scale upon the two stable, naturally existing points of freezing and boiling of water. He designated 0 degrees as water's boiling point and 100 degrees as water's freezing point.

The scale was reversed to its modern form soon after Celsius published his carefully researched proposal. The revised, current scale assigns 0 degrees to the freezing point of water and 100 degrees to the boiling point. David Abbott credits one of Celsius's former pupils at Uppsala University, Swedish astronomer and mathematician Mårten Strömer (June 7, 1707-Jan. 2, 1770) as the scale reverser (page 35). Other candidates include Celsius himself; French astronomer, mathematician and physicist Jean-Pierre Christin (May 31, 1683-Jan. 19, 1755); Swedish instrument maker Daniel Ekström (1711-June 30, 1755); and Swedish botanist, taxonomist and zoologist Carl Linnaeus (May 23, 1707-Jan. 10, 1778).

The takeaways for near side's Celsius Crater honoring Swedish astronomer Anders Celsius are that the lunar impact crater resides in the near side's cratered southeastern quadrant, with Mare Nectaris (Sea of Nectar) to its northeast and Mare Nubium (Sea of Clouds) to its northwest; that Crater Celsius parents five satellites; and the crater eponymizes the 18th-century Swedish astronomer, who is known as the proposer of the Celsius scale of temperature and as the founder of Sweden's oldest astronomical observatory.

Illustration of thermometer with proposed temperature scale accompanied Swedish astronomer Anders Celsius's paper published in the Proceedings of the Swedish Royal Academy of Sciences (Kungliga Svenska Vetenskapsakademiens Handlingar), vol. III (July August September), page 238 (Figure 1): Public Domain, via Biodiversity Heritage Library

Acknowledgment

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

Image credits:

Crop of Lunar Orbiter 4 photograph, taken in 1967, shows Celsius Crater with interior satellite H (center; between 10 and 11); sun angle at 68.3 degrees, spacecraft altitude at 2973.34; D. Bowker and K. Hughes, Lunar Orbiter Photographic Atlas of the Moon (1971); 1967 Lunar Orbiter IV photograph IV-88-H3 Plate 420: National Aeronautics and Space Administration (NASA), Public Domain, via NASA NTRS (NASA Technical Reports Server) @ https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730005152.pdf

Illustration of thermometer with proposed temperature scale accompanied Swedish astronomer Anders Celsius's paper published in the Proceedings of the Swedish Royal Academy of Sciences (Kungliga Svenska Vetenskapsakademiens Handlingar), vol. III (July August September), page 238 (Figure 1): Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/46904413

For further information:

Abbott, David. The Biographical Dictionary of Scientists: Astronomers. New York NY: Peter Bedrick Books, 1984.

Beckman, Olof. "Anders Celsius." Elementa, vol. 84, no. 4 (2001): 174-180.
Available @ https://www.astro.uu.se/history/celsius.pdf

Bowker, David E.; J. Kenrick Hughes; Lunar and Planetary Institute. “Digital Lunar Orbiter Atlas of the Moon.” USRA LPI (Universities Space Research Association’s Lunar and Planetary Institute) > Resources.
Available via Universities Space Research Association’s (USRA) Lunar and Planetary Institute (LPI) @ https://www.lpi.usra.edu/resources/lunar_orbiter/book/lopam.pdf

Bowker, David E.; and J. Kenrick Hughes. “Photo No. IV-88-H3 Plate 420.” Lunar Orbiter Photographic Atlas of the Moon. Prepared by Langley Research Center. NASA SP-206. Washington DC: National Aeronautics and Space Administration Scientific and Technical Information Office, Jan. 1, 1971.
Available via NASA NTRS (NASA Technical Reports Server) @ https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730005152.pdf
Available via Universities Space Research Association’s (USRA) Lunar and Planetary Institute (LPI) @ https://www.lpi.usra.edu/resources/lunar_orbiter/bin/info.shtml?217br />

Celsius, And. (Anders). "Observationer om Twänne Beständiga Grader på en Thermometer" (Observations about two stable degrees on a thermometer). Kungliga Svenska Vetenskapsakademiens Handlingar (Proceedings of the Royal Swedish Academy of Sciences), vol. III (July August September 1742): 171–180 and 232 (Fig. 1).
Pages 171-180: Available from Natural History Museum Library, London via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/46904351
Page 232: Available from Natural History Museum Library, London via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/46904413
Pages 171-180: Available from Natural History Museum Library, London via Internet Archive @ https://archive.org/details/kungligasvenskav1317kung/page/171/mode/1up?view=theater
Page 232 (Figure 1): Available from Natural History Museum Library, London via Internet Archive @ https://archive.org/details/kungligasvenskav1317kung/page/n264/mode/1up?view=theater

Celsio, Andrea. De Observationibus pro Figura Telluris Determinanda (Observations on Determining the Shape of the Earth). Upsaliae [Uppsala, Sweden]: Typis Höjerianis, 1738.
Available via Google Books @ https://books.google.com/books?id=5IBbAAAAQAAJ

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