Rükl Index Map
Jim Mosher and Danny Caes
(the format of this table is copied from the one used by Antonio Cidadão in his Moon-"Light" Atlas)
Additional Information
- Each sectional map provides links to websites containing descriptions and additional information about the features lying within that map zone. These include the Planet Moon web pages compiled by the Lunar Section of the U.A.I. (the Italian national amateur astronomy organization), which include high-contrast "solarized" versions of the actual Rükl maps with most of the labeling omitted; and Akkana Peck's Hitchhiker's Guide to the Moon pages, which include verbal observing notes.
- In almost each one of Antonin Rukl's 76 zones, the Sherlock Holmes of the Moon (Danny Caes) included additional descriptions of less-known formations, disallowed and unofficial names, and nicknames (bold), and also unofficially named basins (all of these basins are not mentioned in Rukl's original charts).
- There's also the Caes-catalog of odd surface formations, all observable through common and powerful telescopes. Locations of the surface formations related to Antonin Rukl's 76 maps.
- For an alternative (but as yet unfinished) index to THE MOON Wiki using a different division of the Moon's nearside see the OPAM Index.
Technical Details
- The map images were produced by re-mapping Earth-based photos using the freeware Lunar Terminator Visualization Software (LTVT) and automatically labeling them using a complete list of IAU approved lunar surface feature names.
- The labels in the main maps include all official feature names falling within the area displayed, with the exception of the lettered craters -- whose positions are shown only on the supplemental maps shown later on the page. However, LTVT can only plot one name at a given pixel location and there are a few cases where two names are assigned identical IAU coordinates (for example, a crater and a rima named after it), and others where they are so close they fall on the same pixel at the map scale (for example, many Apollo landing site names and IAU-approved minor feature names that originated on the highly detailed NASA topophotomaps. In such cases only the first name in the IAU list that appears at a given pixel location is printed on the map. Although some names are missing for this reason, it is important to understand that since the program is told to print every name, the absence of any name or mark at a given location indicates that the feature at that position has no IAU-approved name. The text list following the map includes all names (whether they are printed on the map or not).
- Feature locations are indicated by colored dots (add the feature's official center) with the name printed to its right. Yellow dots indicate non-crater features. Blue dots are used for craters less than 50 km in diameter, green dots for craters between 50 and 100 km in diameter, and red dots for craters over 100 km in diameter.
- The supplemental maps showing lettered craters include circles representing the official IAU diameters (to scale) of each feature. This can help in visualizing the pattern of named features, some of whose visibility varies with lighting angle. Although the parent feature after which a lettered crater is named is not explicitly indicated, it can often be guessed: if the "parent" is a nearby crater, then the letter is placed next to the dot at a clock position pointing towards the parent. Drawing an imaginary line from the dot through the letter should lead to the parent, although the parent feature is often on a different map sheet from the satellite, and may have to be identified by clicking on neighboring map sections. If a lettered crater is named after a non-crater feature (such as "Pico B" named after Mons Pico), the letter is printed directly over the feature position.
- As can be seen in the index map, the Rükl zones were defined to have a "portrait" format suitable for publication in a book. A square format seems more appropriate for display on a Wiki page. As a result, the maps provided here show exactly one Rükl zone (one-eighth the Moon's diameter) vertically, but have been expanded horizontally with information from neighboring zones to fill out the square. Although feature names are printed in these "bonus" areas, each page provides links only to the features whose centers fall within the Rükl zone (that is, between the vertical white lines). The supplemental maps showing lettered crater locations by quadrants (quarter-sections of Rükl zones) have a bonus area on all sides, providing overlap with the neighboring quadrants in all directions.
- Most of the images used for the main maps are mosaics covering the entire lunar disk and they were "registered" in LTVT using two points of known position -- often well outside the area displayed. The mosaics frequently have geometric imperfections causing selected areas to be displaced slightly from their expected positions. As a result the feature dots (whose IAU positons are correctly plotted relative to the coordinate grid) often show a systematic displacement relative to the features depicted in the photo. It is usually easy to correct for this displacement by mentally sliding the photo relative to the dot pattern. The misregistration is particularly serious for images from the Consolidated Lunar Atlas, which frequently exhibit distortions making it possible to register only a small portion of an image at a time, even though they are single frames and should be distortion free.
- If the feature intended by a particular dot is still uncertain after correcting for the systematic offset of the photo, it is best to click on the feature name, locate its LAC zone and then consult the appropriate sheet of the definitive IAU feature identification maps in the USGS Digital Atlas. The latter maps also identify the locations of all IAU approved lettered crater names. The USGS maps are PDF files and they have URL's of the formhttp://planetarynames.wr.usgs.gov/images/Lunar/lac_N.pdfwhere N is the LAC "region" (the number preceding the first letter in the full zone notation).
- In addition to making no effort to remove systematic offsets of dot positions, no effort has been made to avoid "name collision" (instances where the feature dots are so close together that the printed names overlap one another). Again, the appropriate LAC map sheet from the USGS Digital Atlas should be consulted to resolve ambiguities.
