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NASA SP-241: Atlas and Gazetteer of the Near Side of the Moon

(glossary entry)


This book, prepared by the Mapping Sciences Laboratory of the NASA Manned Spacecraft Center in Houston with the assistance of LPL selenographer Ewen Whitaker, and published in 1971, is a forerunner of the latest version of the USGS Digital Atlas of the Moon in the sense that it is a semi-independent effort to document the then-current IAU nomenclature as accurately and completely as possible on a photographic base. More specifically, it was the result of an on-going effort to unambiguously indicate with dots on Lunar Orbiter images the locations of every feature name on the Moon’s nearside that might be used in planning Apollo missions. It includes the Greek-lettered peaks and Roman-numeraled rilles that the authors regarded as significant. Each name is carefully cross-referenced to the corresponding catalog number in Blagg and Müller and the "LPL list" (= System of Lunar Craters), and a complete list is given of every Lunar Orbiter IV photograph in which that feature was imaged and labeled. It also includes a list of images from other Lunar Orbiter missions on which selected features can be seen.

Additional Information

When first published, this book received a rather critical review by Don Wilhelms of the USGS, citing many errors (some brought to his attention by Whitaker himself). Oddly, it is not mentioned in Whitaker’s own otherwise comprehensive book on the history of lunar mapping and nomenclature.

Added note: I had the job of checking all the nomenclature for this book before it was published. When I finished, Ewen and I went to JSC in Houston (we were both at the Lunar Lab in Tucson then) to let Danny Kinsler know the results. Sadly, my copy of 241 has disappeared. - tychocrater Jun 24, 2007

Scanned Sections

The Catalog

The following is a preliminary scan of the Index to the labeled images in SP-241, which also serves as a nearside feature names catalog and a feature-based index to the Lunar Orbiter IV imagery.

  • Note: Ewen Whitaker circulated a list of errata which have been corrected in this version of the scanned catalog, but there are still many scanning/optical character recognition errors, and SP-241 itself contains many errors not on Whitaker's list.

The Index consists of lines with five data fields separated by tab characters. It can be read as a text file, but will display more clearly if downloaded to disk and opened with a spreadsheet program such as Microsoft Excel or its Open Office equivalent.

The five data fields represent:

  • FEATURE IDENT. - IAU-approved name of feature
  • B&M - catalog number (if any) of feature in Blagg & Müller's Named Lunar Formations
  • LPL - catalog number (if any) of feature in the "LPL list" (System of Lunar Craters)
  • LONG. - selenographic longitude (unfortunately not given for all features)
  • LAT. - selenographic longitude (unfortunately not given for all features)
  • PHOTO NO. - frame numbers from Lunar Orbiter IV on which the feature is identified in the illustrated portion of the book

Fields which are blank in the text are filled with the character string "-999". These can easily be restored to blanks using the spreadsheet's Search/Replace function, if desired. SP-241 does not list diameters or any other characteristics of the features depicted.

Discrepancies with Current Nomenclature

Although not an IAU publication, NASA's SP-241 seems to have been regarded as the perfection of the System of Lunar Craters, and was acknowledged in the IAU's 1973 Reports on Astronomy as "the best summary, to date, of lunar nomenclature for the near side of the Moon."

Unfortunately the current IAU Planetary Gazetteer originates from different sources, with the lettered craters, in particular, having been added based on their listings in the non-IAU-approved catalog NASA RP-1097. RP-1097 changed and/or dropped many of the nearside lettered designations, added letters for the farside, and adopted certain changes to non-lettered feature nomenclature recommended by the IAU subsequent to the publication SP-241. It is therefore of some interest to see how the current IAU nomenclature differs for the older IAU-approved nomenclature represented by SP-241, and used on many older maps (such as Rükl) that, in trying to conform to the then-current IAU standards, may have chosen to ignore the NASA-recommended (but unapproved) changes of RP-1097.

It should perhaps be noted that SP-241 itself differs substantially for the original IAU-nomenclature of Blagg and Müller, reflecting many changes introduced in the IAU approvedSystem of Lunar Craters.

The following is a preliminary computer-generated list of discrepancies between the nearside lunar nomenclature of the current IAU Planetary Gazetteer and the nearside earlier nomenclature archived in SP-241:

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