In general, each chapter covers its region with two sets of g images, those intended for overlapping, contiguous coverage, J2 and those that are samples at higher resolution. Each cono) tiguous coverage image is presented twice, once with anno-~ tations and once unmarked. o v'6Annotated Images
«> The annotated images show the named features recognized S; by the International Astronomical Union (IAU). Each fea-
0 ture is outlined, either by the staff of the Lunar and Plane Fetary Institute or by the present author. A few small named
1 features (less than 50 km in diameter) are not annotated, for practical reasons. Since the images overlap, some features appear on more than one image. All annotated features are listed in an index.
and after the feature name in the text. Capital letters are used for IAU named features and small letters are used for other features mentioned in the notes.
Smaller craters of interest to researchers but too numerous to be assigned specific names are designated by the name of a nearby feature, followed by a single letter (Tsiolkovskiy W, for example). The IAU recognizes these designations. The lettered craters are not annotated in this book unless they are specifically mentioned in a note.
On the near side of the Moon, these letters have not been assigned systematically. However, on the far side, a convention proposed by Ewen Whitaker (Whitaker, 1999) has been adopted. In this convention, the letter is chosen according to the approximate direction from the named feature, using the 15° divisions of a 24-h clock face as a guide. The numbers 1 through 24 are replaced by the letters A through Z, with the omission of I and O. The direction indicated by Z points due north.
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