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Janssen & vicinity

2005.08.22 -18:56UT Moon Age 17.5 days 10-inch f/6 Newtonian + 4X Barlow + ToUcarn

(mosaic of 3 video dips)

Janssen and Vailis Rheita

2004.12.17 -10:04 LIT Age 5.4 days Inconstant shy with drifting clouds 10-in f/6 Newtonian + 2.5X + ToUcam (mosaic of 3 video clips)

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Janssen (d/a. i93 km^l Rimae Janssen Lockyer ("34 Fabric!us (7B AmJ Metius (87km) Brenner (97 km) Rheita (70 km) Rheita E (32 x 66 km) Vaiüs Rheita (450 km long) Young (71 km) Mallet (58 km) Reimarus (48 km) Steinhei! (67 km) Watt (66 km) Wohler (27 km) Neander (50 km) Reichenbach (71 km)

Janssen 40.30 E 45.40 S

A large walled formation with craters, rilles and mountain massifs on its floor, 199 km in diameter. It is highly eroded by impacting debris and hence must be very ancient. The system of curved rilles that crosses the southern floor is Rimae Janssen, length about 120 km. So far no one knows how these curved rilles formed. The northwest wall of Janssen is broken by the fairly large crater Brenner (97 km).

Fabricius 42.00 E 42.90 S

This crater hits on Janssen. It is 78 km in diameter, with a small central peak. At one observation with small telescope, the wall appeared double, making it look as though one crater is almost perfectly centered in another. However, high-power telescopes confirm this is not a double wall but a lumpy ridge like a horse-shoe.

Metius 43.30 E 40.30 S

A crater joining the walls of Janssen and Fabricius, 87 km in diameter, with a low central peak.

Vallis Rheita 51.50 E 42.50 S

Vallis Rheita is a long valley near Janssen, 450 km in length, width up to 30 km. It begins from the outer rim of Rheita (70 km), passes through Young (71 km) and Mallet (58 km), then ends beyond Reimarus (48 km). The floor of Vallis Rheita appears as a chain of overlapping craters more than a true valley. The chain also points to Mare Nectaris (T056B, Map 3|), suggesting it was created by secondary impacts during the formation of Nectaris basin. Rheita E is an elongated crater-valley feature, 32 x 66 km, probably created by the fusion of few pre-existing craters or by a grazing secondary impact during the formation of Janssen.

Young 50.90 E 41.50 S

A shallow crater superimposed on Vallis Rheita, 71 km in diameter.

Steinheil 46.50 E 48.60 S Watt 48.60 E 49.50 S A pair of overlapped craters, each about 67 km in diameter. The east inner wall of Steinheil houses a group of small but noticeable craters (T228).

Mare Australe 93.00E 38.90S (Image T188)

Mare Australe (Southern Sea) is on the south-east limb, overlapping the nearside and farside of the Moon. It is a difficult object due to foreshortening. Its dark irregular shape stretches 350 X 350, covering a span of about 600 km. In Lunar Orbiter mapping, nearly 200 craters of different sizes are scattered in this mare, hence scientists thought Australe could be the most ancient mare among all. Lyot (84.50E 49.80S) is a large flooded walled plain lying within Mare Australe, 132 km in diameter. More details in Farside map.

Vallis Rheita 20M.08.31 19:59UT AgeiSdays

2006.03.09 -14:11 UT Moon Age 9.6 days Libration /= 5.2° b - -6.5° {favorable) 10-in f/6 Newtonian + 2.5X + ToUcam (mosa/c)

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