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Thales (and Strabo east of it)

Lat: 61.73°N, Long: 50.28°E, Diam: 30.75 km, Depth: 3.2 km, Rükl: 6, Copernican

external image normal_Thales060105.jpgexternal image normal_Thales-LO4-080-h1.jpg
Left: Howard Eskildsen, Thales is the smaller one of the two craters in the center of the image. The larger companion is Strabo.
Right: LO4-080-h1


LPOD Photo Gallery Lunar Orbiter Images


(LAC zone 14A2) USGS Digital Atlas PDF



(IAU Directions) THALES.--A bright formation, also associated with the N. side of De la Rue, adjoining Strabo on the N.W. Schmidt shows a minute hill in the interior.



Additional Information

  • IAU page: Thales
  • Depth data from Kurt Fisher database
    • Westfall, 2000: 4.54 km
    • Cherrington, 1969: 1.79 km
  • Measures on LRO QuickMap give depth about 3.2 km
  • Measures on LRO QuickMap give central peak height about 310 m
  • Included in ALPO list of bright ray craters
  • Edward Emerson Barnard at Lick found the bowl of Thales filled with pale luminous haze one night in 1892. Source: V.A.Firsoff's The Old Moon and the New (1969), page 183.- DannyCaes May 19, 2012
  • The same phenomenon (E.E.Barnard's 1892 observation of pale luminous haze in Thales) is also mentioned in Patrick Moore's New Guide to the Moon (1976), page 202.- DannyCaes May 19, 2012


- Thales of Miletos (ca. 624 BC – ca. 546 BC) was a pre-Socratic Greek mathematician, astronomer and philosopher and one of the Seven Sages of Greece. Many regard him as the first philosopher in the Greek tradition as well as the "father of science".
- de Ulloa (plate T. LXXIII) (name first used by Van Langren). This formation is limbward of Schröter's "Thales", which in turn appears to be the modern Strabo. Schröter's "de Ulloa" is most likely Antonio de Ulloa (1716–1795) who participated in the French expedition to Ecuador to measure the length of an arc of the terrestrial meridian. Van Langren's "de Ulloa" might possibly be Francisco de Ulloa an earlier Spanish explorer. Research Jim Mosher and Danny Caes

The Bessel Ray (is Thales the source?)

The 21st Century Atlas of the Moon (Charles A. Wood/ Maurice J.S. Collins) is perhaps the very first lunar atlas which has a name for the mysterious high-albedo ray running across Mare Serenitatis and crater Bessel. This ray is one of the most stubborn riddles in the history of moon observing and selenography.
What is the source of this remarkable singular ray of ejecta? Is Bessel the source? Or is it perhaps crater Thales to the north of Mare Serenitatis? Or perhaps crater Menelaus at the southern rim of Mare Serenitatis?
It's very strange that this kind of pronounced rays (ejecta rays from impact craters) don't have official IAU names.
Anyway, Chart 11 (page 35) in the 21st Century Atlas of the Moon shows the informal name Bessel Ray just north of crater Bessel.
How many (ancient or recent) moonbooks have a description of the mysterious Bessel Ray in Mare Serenitatis?
- DannyCaes Aug 16, 2015

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Graphic LAC No. 14. Excerpt from the USGS Digital Atlas of the Moon.


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