Onjala Observatory Mondaufnahmen

		CHAMÄLEON + ONJALA OBSERVATORY – LUNAR ATLAS Segment 11	back to OVERVIEW HOME CHAMÄLEON

Moon age 10.5 - 11.6 days (75 - 83 %)

FF-crater Gassendi and dome Ga 1
Liebig 1
Doppelmayer Do1 and Do 2

Moon age 12.1 days - 13.1 days (87 - 95 %)

FF-crater Gassendi + dome Ga 1
Dome Doppelmayer
Dome and Plateau Liebig 1
Dome Palmieri
Mons Hansteen and domes
Putative dome north of Billy A + B
Putative dome near Lohrmann A
Putative plateau near Cavalerius

Moon age 12.8 days + 14.2 days (93 + 99 %)

Grimaldi

Gassendi and Dome Gassendi Ga1 - Moon age 11.6 days (84 %)

Gassendi (101 km) is one of the most interesting FF-crater and is located at the northern rim of Mare Humorum. Gassendi clearly shows the tilt towards the Mare-center. The craters at the southern rim, Doppelmayer and Lee, are also clearly tilted to the center of the Mare. All three craters were flooded by lava which filled the Mare. To the west there is the dome Gassendi ( type C2) with a diameter of nearly 8 km and an height of just 100 meters. It is a bisected dome which is devidedby a narrow rille with a length of about 56 km.

Just south of Gassendi there is the Rima Herigonius. It is a sinusoidal rille which was a lava channel in its active time. Rima Herigonius is difficult to observe, it is only 1 to 2 kilometers wide at the widest points.

Liebig 1 - Moon age 11.6 days (84 %)

Doppelmayer (64 km) and Lee are beautiful examples of so called tilted craters which have been tilted due to the subsidence of the Mare surface and then flooded by lava. Doppelmayer and Vitello (to the east) are also floor fractured crater. Doppelmayer has a strange pyramidal massive central mountain. In the northwest is the Dome Liebig 1 which can be easily observed because of its relatively large height of about 365 meters. Its diameter is about 10 kilometers. A similar dome is Yangel1 in Sinus Fidei.

The dome seems to be located on an intrusive upwarp with a rough surface. To the west the Rima Doppelmayer can be found. It is surrounded by a large area of pyroclastic ash deposits on both sides.

Just southof Liebig 1 there are the two effusive domes Doppelmayer 1 and 2. Both domes are classified as type C1. Do 1 has a diameter of almost 17 kilometer with a height of 400 meters and shows structures on its surface. Do 2 has a diameter of 12.5 kilometers and a height of 160 meters. That feature what looks in our image like a narrow rille turns out to be an elongated caldera in a LRO image.

LRO Liebig 1

The image to the left shows the Liebig 1 area in a LRO image with a resolution of 125 m/px.

Liebig 1 - Moon age 11.5 days (83 %)

See description above.

	Doppelmayer - Moon age 11.5 days (83 %) The Doppelmayer 1 and 2 domes, imaged a few hours before the picture above. With this illumination the domes are better visible than above. The "strange" central mountain of Doppelmayer arises more plastically. In the top left egde of the image there is the concentric double crater Marth, see Segment 9 C
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Moon age 12.1 days - 13.1 days (87 - 95 %)

Gassendi and Dome Gassendi Ga 1 - Moon age 12.1 days (87 %)

See description of Gassendi and Ga 1 above.

With an illumination of 87 % a slightly higher area becomes visible south of Gassendi 1. we would classify it as a putative dome.

Doppelmayer and Palmieri - Moonage 12.1 days (87 %)

At the marked position in this image should be an intrusive dome with a diameter of 13.5 kilometers and a height of 60 meters. On our image there is nothing to see except for a small bright and young impact crater. Even on the LRO image of Palmierithe dome is very hard to see.

The whole area in the west of Mare Humorum is full of linear rilles. Many of it are certainly associated with the Mare. North of Palmieri 1 there is the crater Palmieri with two intersecting rilles on the floor.

Mons Hansteen and Hansteen Ha 1 - Moon age 12.1 days (87 %)

Hansteen 1 (also Hansteen alpha) is classified as an intrusive structure. Its diameter is just below 19 km at the height is only 85 meters. It can be learly seen on our image. To the south there is an upwarp, which can be a putative dome.

Mons Hansteen with its size of 29 x 27 kilometers reaches a height of just over 1000 meters. It is classified as a volcanic structure formed by very slow-moving lava. The spectral reflectance measurements of the surface show strong similarities with those of the Gruithuisen domes.

Gassendi - Mon age 13.1 days (95 %)

East of Gassendi there is an intrusive megadome plateau with the unofficial name "The Helmet". Officially it is called Agatharchides Plateau. For details see Segment 09 C.

Putative Lohrmann A - Moon age 13.1 days (95 %)

When having a look at the terminator near the crater Lohrmann A (12 km) at an illumination of 95 % there is a small upwarp which can be a putative lunar dome.

Putative Cavalerius - Moon age 13.1 days (95 %)

Another putative plateau lies further north, near the crater Cavalerius (7 km). It is a flat upwarp, which seems to be crossed by rilles. Directly east of it there is the mysterious structure Reiner Gamma, a so-called "Swirl". On the bottom left a part of the Marius Hills are visible (see Segment 12)

Reiner Gamma is neither a depression nor a bulge of the surrounding countryside. It is a flat, bright oval of 35 kilometers in length with a long tail which extends into the region of the Marius Hills. The oval is the center of a magnetic anomaly. At this point there is the center of a strong magnetic field which is much stronger than the normal lunar magnetic field. It is an absolutely untypical object and the only one on the front of the Moon.

On the back side of the Moon there are a small number of Swirls, which position is antipodal to the big Mare of the front side of the Moon. It is not clear if this is coincidence or not. In any case there is no antipodal Mare on the far side of the moon for Reiner Gamma.

Mondalter 12.8 Tage + 14.2 Tage (93 + 99 %)

Grimaldi Gr 1 - Moon age 12.8 days (93 %)

Grimaldi (222 km) is probably rather a small impact basin than a large crater. In the northern area there is a large intrusive plateau with a lenghth of about 30 km and a height of 160 meters. It has a clearly triangular shape.

	Grimaldi Gr 1 - Moon age 14.2 days (99 %) At a moon age of about 14 days, the triangular structure is clearly visible. On the surface of the dome are at least 6 very small effusive structures visible. The shape of the whole plateau is similar to Mons Rümker.
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