Lunar & Planetary Laboratory Catalog of Lunar Craters

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Lunar & Planetary Laboratory Catalog of Lunar Craters

(glossary entry)


Following the completion of the System of Lunar Craters a new cataloging project started at the Lunar and Planetary Lab. From 1969 through 1973 I led the new work, directing a small team of undergraduates in the measuring of all craters larger than 7 km diameter (and lettered ones of any diameter) on enlargements of Lunar Orbiter IV photographic prints. The large scale and high resolution of the Orbiter images permitted more accurate measures of crater diameters and for the first time in any catalog, systematic determination of crater depths through shadow length measurements. The overhead view of Orbiter images also made it easier to interpret craters along the limb, clearing up many previous ambiguities of what was and was not a crater.

The new effort was to catalog craters on the entire Moon, and subdivided the work into 6 sections, as if the Moon were a cube rather than a sphere. When I left the Lunar and Planetary Lab in 1973 to teach in Africa, the Earth-facing side of the cube was complete, including new maps such as those in the System of Lunar Craters, as were most of the limb regions of the nearside. The document was to be published by NASA as Lunar & Planetary Laboratory Catalog of Lunar Craters: Pt. 1: Nearside with C.A. Wood and L.E. Andersson as authors; it even received a NASA publication number - NASA TM 79328 - but it was never published.

The problem was that I was out of the country and out of the picture. My letters asking when it would be published were answered that it was almost ready, but it never happened. In the mean time Leif Andersson had replaced me as project leader and he led the cataloging of just the named and lettered craters of the farside. But then Leif died (tragically early in his life) and the catalog languished. I had returned to the US and was in graduate school on the other side of the country, and couldn't force it to be published. The hold up was that the maps for the farside had not been checked and probably had errors in them. I finally said, Fine, lets just publish the catalog and forget the maps, but that never happened.

All was not lost. In 1974, Dai Arthur, who had written the procedure to calculate crater depths from shadow measurements, published - as sole author - the reduction method and a list of depths and diameters for the 1933 named and lettered craters falling in the central “face” of the lunar cube (roughly, within 45 degrees of the Moon’s center). Arthur’s table lists the depths and diameters to the nearest 0.01 km, as well as giving the position-based catalog number (in the new "LPL Catalog of Wood et al., in press"), the “class number” (according to an unexplained system developed in the System of Lunar Craters), and the number of the Lunar Orbiter photo on which the measurements had been made. And later, after Leif's death, Ewen Whitaker organized and published (as Andersson and Whitaker) the NASA Catalog of Lunar Nomenclature which contained all of the LPLCLC lat, longs and diameters for nearside and farside named and lettered craters. Ewen had assigned letters to 1667 farside craters. The NASA Catalog of Lunar Nomenclature is the basis for post-Apollo lunar nomenclature.

In the late 1970s I received a printout of the LPLCLC nearside craters that had names and letters. I still have that, but not the entire catalog. Apparently, no copy exists of the entire LPLCLC. What has been lost by not publishing the LPLCLC is a modern, high quality cataloging of the entire Moon. Like the System of Lunar Craters, the LPL Catalog (at least the nearside) included information on rim sharpness, the presence of central peaks and terraces, and diameters of floors. The only comprehensive catalog that contains such morphological information is the ancient (and nearside only) System of Lunar Craters, based on photographic images in existence in 1960 (the Photographic Lunar Atlas. The failure to publish the LPLCLC has resulted in the loss of all of the diameter, depth and morphology information for thousands of craters lacking letters. All of the farside crater depths are gone, as are the precise diameters, measured to the nearest 0.001 km, but published in the NASA Catalog of Lunar Nomenclature only to the nearest kilometer. This is a tragedy for lunar cartography.

- tychocrater Nov 11, 2007

Additional Information

LPOD Articles

A New/Old Catalog of Lunar Craters