• Don SpainEmail author
Part of the Astronomer's Pocket Field Guide book series (ASTROPOC)


Janssen (115 miles) is another of the lunar giant craters. The large crater Fabricius is almost entirely within its rather low walls. There are many other craters inside this behemoth. Under grazing sunlight at about 5 days after new Moon, this formation can be seen with 10 power binoculars. There is a low central peak near the center and two great rills. These rills are easily seen on the photo, forming a great arc from Fabricius to Janssen’s southeast wall. The northern floor is rough and there is a nice 16 mile diameter crater perched on the northern rim. Though old and battered, under low sunlight Janssen is a must to explore with any size instrument.

Fabricius (47 miles) is a deep crater with a rim that reaches well over a mile above the floor. There is a well formed central mountain mass as well as a small range of mountains to the north. The walls are terraced.


Small Range Central Peak Diameter Crater Mountain Mass Large Crater 
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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Louisville Astronomical SocietyLouisvilleUSA

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