POSIDONIUS Exploring the Moon Series
POSIDONIUS Exploring the Moon Series
POSIDONIUS Exploring the Moon Series
This magnificent ring-plain is justly regarded as one of the finest telescopic objects in the first quadrant. Its narrow bright wall with its serrated shadow, the conspicuous crater, the clefts and ridges and other details on the floor, together with the beautiful group of objects on the neighbouring plain, and the great Serpentine ridge on the E., never fail to excite the interest of the observer. The circumvallation, which is far from being perfectly regular, is about 99. 7 kilometers (62 miles) in diameter, and, con sidering its size, is not remarkable for its altitude, as it nowhere exceeds 1 828 meters (6000 feet) above the interior, which is depressed about 609 meters (2000 feet) below the surrounding plain. Its continuity, especially on the East side, is interrupted by gaps. On the North side, the wall is notably deformed. It is broader and more regular on the W., where it includes a large longitudinal depression, and on the
N. W. section stand two bright little ring-plains. On the floor, which shines with a glittering lustre, are the well-marked re mains of a second ring, nearly concentric with the principal rampart, and separated from it by an interval of nine or ten miles. The most prominent object, however, is the bright crater a little E. of the centre. This is partially surrounded on the W. by three or four small bright mountains, through which runs in a meridional direction a rill-valley, not easily traced as a whole, except under a low sun. There is another cleft on the N.E. side of the interior, which is an apparent extension of part of the inner ring, a transverse rillvalley on the N., a fourth quasi rill on the N.W., and a fifth short cleft on the S. part of the floor. Between the principal crater and the S.E. wall are two smaller craters, which are easy objects. Beyond the border on the N., in addition to Daniell, are four conspicuous craters and many ridges.
A great Posidonius Image by Ozz
