May 24, 2009
Tiny New Rille & Broad Mare Ridge
image by Pascal Bayle, France. Original below, enhanced above.
Features that used to be nearly unknown a decade ago are now becoming familiar. The Marius Rille, a sinuous, long lava channel that seems languidly draped across southern Oceanus Procellarum is a case in point. Rükl gives a length of 250 km, with the width narrowing from 2 km near its starting position (right) to to 500 m at its end (left), where it is still visible in Pascal's image. This image also shows what appears to be a fainter rille near top-left that I don't remember noticing before. But looking back it is just visible on a Lunar Orbiter IV image and a previous view of the Marius Rille (which also includes nomenclature). This short rille appears to be more tightly sinuous than the longer one. I keep having vague recollections that I must have seen it before - perhaps in Apollo images - but I can't find any view better than Pascal's. Another subtle thing to notice is the great width of the swell associated with the unnamed mare ridge at the upper left - see the sharp, but shallow change in slope just west of the crater Marius P?
8 Jan 2009 at 20:54:31 ut. 14" scope + DMK 21AF04 + POWERMATE x2.5
Rükl plate 18
Yesterday's LPOD: Rilleorama
Tomorrow's LPOD: The Case of the Missing Mare