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Gerard - and the Gerard Q Inner / Gerard Q Outer complex

Lat: 44.5°N, Long: 80.0°W, Diam: 90 km, Depth: 2.2 km, Rükl: 8

external image normal_Gerard_LO_iv_189_h2.jpg
LOIV-189-H2 The IAU's Gerard is the complex, three-part enclosure in the center of this Lunar Orbiter view, which has north at about 11 o'clock. Directly above Gerard the dark-floored snowman shape consists of 27-km Gerard C and an unnamed crater above that. On the left, the sharp, deeply shadowed crater is Gerard A . The dark lava-flooded 60-km diameter feature partially visible in the upper left corner is one of two lettered craters known as Gerard Q. This one is officially called "Gerard Q Inner" to distinguish it from the much larger 190-km "Gerard Q Outer", which is more or less concentric with the former, and cuts through Gerard a little to the southwest of Gerard A, sharply truncating the "primary" crater's rim. The rille to the west of this point (to the lower left of Gerard A) is probably part of Rimae Gerard. The crater chain in the hills below it is not named.


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(LAC zone 22A1) USGS Digital Atlas PDF


Description: Elger

(IAU Directions) GERARD.--A large enclosure close to the limb, still farther N., containing a long ridge and a crater.

Description: Wikipedia


Additional Information

Depth data from Kurt Fisher database
  • Viscardy, 1985: 2.2 km


  • Named for Alexander Gerard (February 22, 1728 - February 22, 1795), a philosophical writer and Professor of Natural Philosophy. As a professor he introduced various reforms.
  • According to Whitaker (p. 219), this name was introduced by Mädler and adopted into the original IAU nomenclature with his spelling: Gérard. At the insistence of Gerard Kuiper the accent was removed from the "e" in the early 1960's. - Jim Mosher
  • The odd IAU naming of two of the satellite features of Gerard as Gerard Q Outer and Gerard Q Inner seems to have arisen in the System of Lunar Craters (1961-1966) where two craters, one inside the other, were both labeled with the letter "Q". This seems to have been intentional, for according to Chuck Wood they are listed as "inner" and "outer" in the Communications of the LPL tables that accompanied the maps, where they are given diameters of 60 and 177 km. Was this meant to define Gerard Q as an annular zone?? The "inner"-"outer" notation was also used on NASA's Lunar Polar Map LMP-3 (1976), where the map makers seem to regard these as two separate features distinguished as Gerard Q (inner) and Gerard Q (outer). A similar notation, but with the parenthesis omitted, was used (again without further explanation) to distinguish the two listings when NASA's RP-1097 catalog was issued in 1982, however the diameters are given there as 7 and 18 km, which seems a factor of 10 smaller than the sizes illustrated on the SLC and LMP maps. Because the names, positions and diameters of lettered craters listed in the on-line IAU Planetary Gazetteer are based on RP-1097 (rather than the previously IAU-approved System of Lunar Craters) this error(?) is perpetuated there. - Jim Mosher
  • Gerard Q inner was misprinted as GERALD Q INNER (with "L") on LAC 22 (page 45) in the Revised and Updated Edition of the Clementine Atlas of the Moon (Cambridge University Press, 2012).- DannyCaes Jan 7, 2013
  • The same mistake (Gerald, with "l") was made on page 69 (chart 28) in the 21st Century Atlas of the Moon (2012).- DannyCaes Jan 23, 2013

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