It is usefull to observe the moon crescent at its shade border, the terminator passing the moon in a 14.5 day rhythm. Thus at the 5th evening after new moon in September 2000 I shot the 1. Picture. Having an enlargement of 40 the crescent appears at your eyepiece completely. Clearly you can identify the following 3 Oceans with help of numbers::
* sea of nectar (1)
* sea of fertility (2)
* sea of danger (3)
The sea of nectar has a diameter of 218 Miles (350 km). It is approximately 3.9 billion years old. To get a better orientation, a compass symbol is given in the upper left of the picture. Maybe you wonder that I selected the north direction downward, but with a refractor telescope the objects appear upside down. 3 craters impressed me particularly at the west edge of the sea of nectar:
* Catharina (4)
* Cyrillus (5)
* Theophilus (6)
Further the ‘x’ indicates the approximate landing point of the manned moon mission Apollo 17. Since the seeing was good this night (R2), I could shoot a detailed picture of this area with an enlargement of 100. Take a look at the 2. Picture.
In the south of the sea of nectar the crater Fracastor (3) is located Fracastor has a diameter of 77 miles (125 km). Its same dark color points on the fact, that it is filled with lava, which penetrated over its north barrier from the sea of nectar. The missing central mountain is a further indication for this event. The crater Catharina (4) is the oldest of the 3 craters. It has a diameter of approximately 62 miles (100 km) and its barrier has an altitude of about 3000m. Looking to direction NNO you identify the crater Cyrillus (5) and Theophilus (6). The last one is characterised by a remarkable central mountain. Theophilus is the youngest of this trio, which con be recognized by its intact barrier reaching into Cyrillus. You should pay special attention to the "ghost crater" Beaumont (7). Ghost craters are created in a normal way, but later have flooded by lava of the mare. Nowadays you still can recognize the edges of its barrier. Other ghost craters show a circular depression only. East of Theophilus you discover the "young" Maedler (8). It separates the sea of nectar from the bay of roughness in the north. Also a matter of interest is the pair Isidorus (9) and Capella (10). Looking exactly, you recognize that Capella is younger than Isidorus. In this picture the sea of fertility is marked by number 2.
At the 11th night after new moon in September 2000, similar visibility conditions as at the 5th night could be reached. The 3. Picture represents an observation with an enlargement of 100. The sea of the humidity (1) has a diameter of 236 Miles (380 km). If you go northward (remind that a refractor turns a picture upside down), you find the dominating crater Gassendi (2) . It measures approximately 56 to 62 miles (90 - 100 km) and includes a group of central mountains with 3 summits. Unfortunately they are not dissolved in my photo. Clearly you can recognize, that the wall of crater Gassendi was destroyed by Gassendi P (3) which was created later. South of the sea of humidity the crater Doppelmayer (4) is situated, sunk partly. Its diameter measures 40.4 miles (65 km) and the central mountain has an altitude of approximately 1.24 miles (2000 m). Another beautiful central mountain decorates the crater Vitello (5). Its barrier shows a gap in the northeast. Unfortunately at this night I shot my picture 15 minutes to early to observe the Liebigwand and the Mersenius grooves. They are located in western direction nearby number 1, still being in the dark. The Mersenius grooves are probably underground courses, which were flooded by lava and later on collapsed. It is thought that these grooves were created by tectonic drifting of the moon crust, as it is found on earth. With vivid imagination you will make out the ghost crater Puiseux, southeast to number 2, having a diameter of 15.5 miles (25 km) and a barrier attitude of 1200 ft. (400 m).
You perhaps will be surprised, where I found the names of the individual objects.
This information can be derived from the outstanding book::
Der Kosmos Mondführer (The Kosmos moonleader)
Jean Lacroux and Christian Legrand,
Franckh-Kosmos Verlags-GmbH & Co.
It`s only avaiable in German
Read more: Observation of sun
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|Copyright by Hans Joachim Ilgen since 1950|