System of Lunar Craters

The System of Lunar Craters (SLC)

(by D.W.G. Arthur, A.P. Agnieray, R.A. Horvath/Pellicori, C.A. Wood, C.R. Chapman and T. Weller)

Description

The The System of Lunar Craters is a painstaking cataloging of all nearside lunar craters with diameters larger than 3.5 km was undertaken by the newly established Lunar and Planetary Laboratory at the University of Arizona, beginning in 1961. The work involved measuring the diameter and latitude and longitude of every named and lettered crater on the lunar nearside, plus all other craters larger than 3.5 km. Additional information determined for each crater included rim freshness, whether it was located on highlands or maria, and if it had central peaks or terraces. The System contains information on about 17,000 craters, and published in the form of four quadrant maps and catalogs, the last quadrant being completed in 1966. The catalogs appeared from 1963-1966 in numbers 30, 40, 50 and 70 of the Communications of the LPL and as a series of identical NASA Contract Reports (CR-52401, 57208, 68590, 78466). Each issue included eleven maps illustrating the positions and sizes of all lettered and numbered rilles, peaks, promontories, and other lunar features falling in that quadrant; but the catalogs list only craters. Each crater in the System has a unique 5 digit reference number derived from its position on the lunar surface.
 
  Each named and lettered crater, numbered rille and Greek-lettered peak in Blagg and Müller was carefully compared with photos to check its existence and suitability as a landmark. A number of lettered features (and a few named ones) were deleted, and some new names and many new letters were added for craters and peaks, as were numbers for rilles. Nomenclature excerpts from the System text explain these changes.
 
  A report, mostly describing some of the changes to Blagg and Müller being made in the Rectified Lunar Atlas, but also mentioning the System of Lunar Craters and other works of the day -- such as the LAC maps being prepared by a forerunner of the DMA (which unfortunately don't always agree with the System) and the Quad Maps accompanying the System -- was approved the IAU Lunar Commission in 1964. In a 1967 report, the Lunar Commission's then-Chairman Donald Menzel expressed his hope that the hard work on the System would "be rewarded by wide acceptance." As a result, some version of the System was probably regarded by many as the official nomenclature for the lunar nearside until about 1973, although the bulk of the revisions seem never to have been officially or specifically approved; and, a few paragraphs later in the same report, the Chairman notes the necessity of "a complete review of the problem of nomenclature of various lunar features" in view of conflicting input from experts in the U.S.A. and U.S.S.R.
 
 Ewen Whitaker's interpretation of the System of Lunar Craters as a successor to Named Lunar Formations, from his Short History of Lunar Nomenclature in NASA SP-241 (1971), is as follows:
 
 

• The work was com­pleted in 1966. The new map and catalog, published by quadrants, used a new nomenclature system that the IAU accepted in 1964 and 1967 to supersede the 1935 IAU system. Although the catalog listed only craters, the map designated rilles, peaks, promontories, and other lunar features. The LPL map and catalog were compiled using the best earth­-based lunar photography then available. In 1969, revised maps of the quadrants were issued.

The larger Quad maps described in the preceding paragraph were derived by combining the smaller ones. They were also prepared and published as a stand-alone product (which was probably more widely known and distributed than the catalog). Each Quad map included major updates to nomenclature (such as lettered limb craters receiving names) that had occurred since the original catalog had been published. All of these name changes were approved by the IAU. - tychocrater Jul 26, 2009

SLC Map Sheets

Each quadrant catalog of the System ended with 11 map sheets that showed every crater in the catalog and other peaks, mountains and rilles. The following index shows the numbering of the maps in rows and columns, with links to a copy of each extracted by John Moore from the PDF files of the Communications of the LPL on the LPL website. The maps are plotted south up, with east to the left.
 
 

	A	B	C	D	E	F
8							8
7					external image 185678047?size=64		7
6					external image 185683115?size=64	external image 185683113?size=64	6
5						external image 185683107?size=64	5
4							4
3							3
2		external image 185669305?size=64					2
1							1
	A	B	C	D	E	F

• A legend explaining the symbols used for plotting various feature types (which included lettered albedo "spots") can be found on Sheet A2.
• Fax-quality scans of the 44 sheets, overwritten with lunar domes notations, can be found on the GLR website (seems to be the wrong link, we don't need fashion and clothes, we need lunar domes!!!).

The 44 sections of the SLC-moonmap on yellowish A4 paper, created by a home printer (with additional colored markings)

• On sunday the 15th of January 2017, Danny Caes, the dedicated explorer and investigator of not-so-recent moonmaps and lunar atlases, decided to print the 44 sections of the above shown SLC-moonmap on yellowish-white (light-beige) colored paper (on 44 sheets of classic A4 paper) to write the disallowed (yet very useful) names from Hugh P. Wilkins and Patrick Moore on these 44 sections (blue ballpoint), and also whole series of names from lots of other sources, such as the Lunar Topographic Orthophotomaps (LTO), the Rand McNally moonmap, and all of the Apollo-era names for small surface formations captured on the HiRes photographs made with the Fairchild- and Itek cameras aboard the SIM-bays of Apollo 15, 16, and 17. The nicknames from the early Apollo missions (Apollo 8, 10, and 11) at the equatorial Maskelyne and Secchi region are also included. In other words, the 44 sections of the SLC-moonmap are excellent material to create a much more complete overview of the official and unofficial nomenclature on the moon's near side!!! Thanks Charles A. Wood and his colleagues who created the SLC-moonmap! This is a very, VERY interesting moonmap! Also for those who want to know the locations of the Greek lettered hills and hillocks! Thanks!!! - DannyCaes Jan 14, 2017
• But... on the other hand... none of the Greek letter designations at the coastline of Mare Crisium were included on SLC chart A3 (the northern part of Mare Crisium) and SLC chart A4 (the southern part of Mare Crisium). Was the eastern part of the moon's near side (at and around Mare Crisium) somehow "forgotten" terrain during the making of the 44 SLC charts?
• An additional aesthetic note. This yellowish-white (light beige) paper (on which the 44 sections of the SLC-moonmap are printed) (black ink) looks very much like "yellowish newspaper from the past" (it's like articles from many decades ago, protected in transparent plastic maps, held together in a handy classeur). Call it nostalgia.
• On these prints it's interesting to give the mare-regions (the low albedo areas) a soft light-grey color. To fill these low-albedo regions in with a "H " pencil is, as I think of it, the best way to add the soft grey color. The other pencils ("HB " and "B ") are much too dark! Note: don't use the extremely hard "H-9 " type of pencil, because the sharp point of such a pencil could scratch right through the paper! (for what sort of surfaces are these "H-9 " pencils made? Metal surfaces?).
• Here's the grading chart showing all shades of grey from the variety of graphite pencils, from 9-B (soft point, black) to 9-H (hard point, light grey), see Wikipedia Graphite Pencil Grey Chart.
• There are lots of suspected remains of nameless craters and basins on these 44 charts, depicted as dotted circle-shaped or ellipse-shaped lines. It is interesting to give these black dotted lines the color yellow. You'll be surprised to see how many of these suspected craters and basins there really are! (enough to create a huge catalog of them!). Within mere days you see a yellow moon, because most craters don't have a name or letter designation. The largest of them should be marked light green (the rather difficult to detect basins such as, for example, Balmer-Kapteyn, Schiller-Zucchius, etc...).
• The Greek lettered hills and hillocks need their own color too. I decided to give each one of them a very tiny dot of Magenta color (pink). Many years ago I did the same thing on the charts of the Times Atlas of the Moon (each one of the very tiny and very difficult to trace Greek letters are underlined; Magenta).
• So... this way you create a much more attractive SLC atlas than the colorless one you see in the 44 clickable scans above! - DannyCaes Feb 12, 2017

Additional Information

• The quadrants were numbered following the traditional system, established apparently by Beer and Mädler (Whitaker, p. 121), in which Quad I = northeast (containing Mare Serenitatis), Quad II = northwest (containing Mare Imbrium), Quad III = southwest (containing Mare Humorum), and Quad IV = southeast (containing Mare Nectaris).
• As tabulated in SP-241 it appears that about one-quarter of the named features appearing in the System of Lunar Craters do not correlate with catalog numbers in Blagg and Müller. Many limb craters were given letter designations, reflecting great improvements in knowledge of the limb regions since 1935. - tychocrater Jul 26, 2009
• The published catalog volumes are rare and the only Internet access is to the small maps published in the Communications of the LPL. Until recently the full quadrant maps were sold by Sky and Telescope, and may still be. - tychocrater Jul 28, 2007
• The Rectified Lunar Atlas, illustrating in more detail the Moon's libration zones, was a companion piece to this project, and also endorsed (along with the NASA-sponsored LAC map series) in the same IAU resolutions.
• For an alternative catalog compiled for NASA at around around the same time Boston University's Catalog of Lunar Craters V (1963), one of a series that attempts to list every crater detectable in a small area.
• A few years after the System was completed, measuring the positions and diameters of lunar craters resumed at the LPL. This new work was based on measurements on Lunar Orbiter IV enlargements. This work was completed for the central nearside and in an abridged manner for the farside, and although the nearside catalog received a NASA publication number (NASA TM 79389) it was never published in its entirety. - JimMosher, - tychocrater Nov 11, 2007
• Some of the Nomenclature Text from Quadrant 1 is available on this Wiki. The full text can be accessed via the links in the Bibliography below.

LPOD Articles

Sheets and Quads

Bibliography

• Bibliographic listings of the various volumes of the The System of Lunar Craters can be found in the References section of NASA SP-241.
  • Scanned copies of some of the quadrants are available for on-line reading in a variety of formats on the Internet Archive:
    • Quadrant I
    • Quadrant II
  • The searchable PDF's come from identical copies on the NASA Technical Reports Server:
    • Quadrant I
    • Quadrant II
    • Quadrant III (not scanned?)
    • Quadrant IV
  • Alternate scans are available on the LPL website:
    • Quadrant I
    • Quadrant II
    • Quadrant III
    • Quadrant IV
• Whitaker, E. (1971). I. A Short History of Lunar Nomenclature in NASA SP-241
• Whitaker, E. (1999). Mapping and Naming the Moon

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