Luna Incognita

Luna Incognita

(unofficial name)
 

Lat: 70°S, Long: 105°S, Size: 1200x160 km, Rukl: farside

Left: Early USGS Map from the USGS Historical Lunar Data Archive; Right: Later USGS Map from PDS Map-a-Planet

Images

LPOD Photo Gallery

Maps

LAC zone: mostly 143-144

Description

A major objective of the Lunar Orbiter series of missions in the 1960's was to provide complete mapping of the Moon. Although generally successful, there was a small region starting around the Moon's south pole and extending roughly from Malapert to Mendel for which adequate imagery was not obtained. As a result, the south pole is depicted like an Antarctic ice cap with a huge glaciated valley extending out from it on the early USGS Shaded Relief maps, which were prepared largely on the basis of the Lunar Orbiter observations (there were also some failures on the nearside, most noticeably the eastern portion of Mare Crisium, but they could be filled in with Earth-based observations). This peculiar (but unreal) tract of featureless land is familiar to users of the Virtual Moon Atlas and other such lunar simulation products which rely on this early map.
 
  Likely features in this poorly mapped region were gradually filled in largely as the result of a years-long concerted amateur effort organized by the ALPO's John Westfall and conducted from about 1970-1990. This project drew upon on all available resources, including a carefully coordinated international program of amateur observations from Earth during periods of favorable libration and lighting. Annual progress reports were published in the ALPO journals.
 
  Perhaps in part as a result of Westfall's efforts, the current USGS Shaded Relief map, as used, for example, at PDS Map-a-Planet shows considerably more detail in this region, although it still doesn't match the texture of the surface shown elsewhere, and the reliability (and origin) of the features depicted within it is unknown.
 
  The largest IAU-named feature falling in "Luna Incognita" is the 156-km crater Ashbrook.
 
 - Jim Mosher
 
 

Additional Information

• Before 1994, when the region at and near Shackleton (the moon's south pole and adjacent area near Ashbrook, Drygalski, Hausen, and Petzval) was not satisfactorily photographed by telescopic observers on Earth and by orbital lunar probes, it (the south-pole region) was called Luna Incognita by John E. Westfall. The dedicated Belgian lunar observer Leo Aerts (VVS; Vereniging Voor Sterrenkunde) was one of the investigators of this region. This unofficial name was abandoned after the arrival of the Clementine orbiter in 1994, which made the first clear photographs of this region around the moon's south pole. Research: Danny Caes.

Nomenclature

• The name Luna Incognita was assigned to this region by John Westfall at least as early as 1972 (per first bibliography reference).
• The shaded relief map published on pages 556-557 of the 1991 Sky and Telescope article shows the following provisional names which the text says "have been submitted to the IAU and are pending approval":
  • Ashbrook (approved in 1994)
  • Bartlett (never approved; called Mendel J since 2006)
  • Bonestell (approved for use on Mars in 1997; crater on Moon is Cabeus B)
  • Chappe (approved in 1994)
  • Faustini (approved in 1994)
  • Gant (never approved; the name Pilâtre was selected at the 1991 meeting)
  • Hédervári (approved in 1994)
  • La Paz (never approved for Moon; in use on Mars since 1979, but refers to Mexican City rather than American astronomer; crater on Moon is Pingré S)
  • Nobile (approved in 1994)
  • Palus Solitatis (not approved; referred unnamed mare region at center of Mendel-Rydberg Basin, near Andersson)
  • Shackleton (approved in 1994)

• The outline map on page 559 of the 1991 Sky and Telescope article places a "Boltzman" [sic] label next to Lippmann, a position that had been considered by the IAU in 1970 but never adopted. Boltzman is properly labeled on the shaded relief map on page 557. - Jim Mosher
• Palus Solitatis was probably the same low-albedo region which was once called Mare Parvum by Franz. - DannyCaes Oct 9, 2014
• The names Bartlett, Gant, and La Paz were also used by Hugh Percy Wilkins in his book The Moon. These three names, and many more, were never approved by the IAU (see list in E.A.Whitaker's book Mapping and Naming the Moon, Appendix R, or the online page Unofficial Names of H.P.Wilkins). - DannyCaes Oct 9, 2014
• The name Shackleton was also one of Wilkins's names, but... the IAU decided to throw this name from the lunar northpole straight to the southpole! - DannyCaes Oct 9, 2014

LPOD Articles

Bibliography

• Westfall, John E. (1972) Luna incognita: The last frontier?, Strolling Astron., Vol. 23, pp. 118 - 122.
• Westfall, John E. (1990) Mapping luna incognita, Journal of the Association of Lunar and Planetary Observers, vol. 34 (Nov. 1990), pp. 149-159
• Westfall, J. E. (1991) Luna Incognita Project, Sky and Telescope (November issue), pp. 556-559.
• MacRobert, A. M. (1993) "Exploring the Moon's South Pole". Sky and Telescope, Vol. 86, No. 4 (October issue), pp. 66-67.
• A Portfolio of Lunar Drawings (Harold Hill), pages 188, 189 (the south polar regions).

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