(glossary entry; plural = Valles)
One of 18 different categories of lunar features recognized in the current system of IAU nomenclature. The IAU defines a vallis as a "valley". The term is used as prefix to the feature name.
- In the earlier IAU nomenclature of Blagg and Müller the English word "Valley" was used in the official names, of which there were only three: "Alpine Valley", "Rheita Valley", and "Schröter's Valley". It was the authors' intention that each user would spell names of this sort in their own language. Since the Latinization of lunar names in 1961, the IAU presumably now expects scientists of all countries to use the Latin forms. - Jim Mosher
- At least two features today regarded as valleys were named like "primary" craters in Blagg and Müller (Bouvard and J. J. Cassini). The former of these has been retained in the modern nomenclature as Vallis Bouvard; the latter name was dropped. Other features regarded as "valleys" were assigned capital Roman letter designations, indistinguishable from lettered craters. The original Schröter F is probably an example of this.
- The locations of many additional nearside valleys are indicated on the Quad Maps of the System of Lunar Craters. The precise number of valleys identified is difficult to assess because the graphic used to designate them is slightly ambiguous, consisting of two scarp symbols facing each other. Names were assigned to only four of these: Vallis Baade, Vallis Inghirami, Vallis Palitzsch, and Vallis Snellius.
- Two farside "valleys" were given names in 1970/1971: Vallis Planck and Vallis Schrödinger.
- The (barely) nearside feature Vallis Bohr and two minor parts of Aratus CA were added by the IAU in 1976. The valleys associated with Aratus CA are much smaller and different in origin than virtually all other named valleys. This was an inappropriate use of the term. - tychocrater Jun 4, 2009
- Finally, Vallis Capella was added at some unknown date.
- Most of the newly named lunar valleys are probable basin crater chains, and the ones near Orientale are full of its ejecta. The Alpine Valley is a basin radial feature (as are most valleys) but fundamentally different in look and probably origin than the many newly named valleys. - tychocrater Sep 2, 2007
- List of lunar "valles".