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Apollo 17 Mapping Camera image | |
| Coordinates | 13°30′N 28°42′E / 13.5°N 28.7°E |
|---|---|
| Diameter | 24 km |
| Depth | 0.6 km |
| Colongitude | 351° at sunrise |
| Eponym | Zacharias Janssen |


Jansen is a lunar impact crater in the north part of the Mare Tranquillitatis. The diameter is 24 km. It was named after 17th century Dutch optician Zacharias Janssen.[1] It is located to the east-southeast of the crater Plinius. The rim of Jansen is low and narrow, with a notch along the western edge. The interior is relatively level, which may indicate it has been covered by lava. To the south-southwest a small but prominent crater lies on the crater floor, halfway between the center and the rim.
To the northwest of the rim is a rille named Rima Jansen, and to the east are wrinkle ridges in the mare surface. A low ridge runs from near the southeast rim in a southeasterly direction.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Jansen.
| Jansen | Latitude | Longitude | Diameter |
|---|---|---|---|
| D | 15.7° N | 28.4° E | 7 km |
| E | 14.5° N | 27.8° E | 7 km |
| G | 9.3° N | 26.0° E | 6 km |
| H | 11.4° N | 28.4° E | 7 km |
| K | 11.5° N | 29.7° E | 6 km |
| L | 14.7° N | 30.1° E | 7 km |
| R | 15.2° N | 28.8° E | 25 km |
| T | 11.4° N | 33.5° E | 5 km |
| U | 11.9° N | 32.3° E | 4 km |
| W | 10.2° N | 29.5° E | 3 km |
| Y | 13.4° N | 28.6° E | 4 km |
The following craters have been renamed by the IAU.
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