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


Fracastorius (75 miles) is the remains of what once must have a great formation. The floor is flooded by the Sea of Nectar, the great lava sea to its north. The rim is very low in the north and indeed part of it is missing completely. The southern walls are much higher, perhaps rising up to a mile or more above the floor. Notice the 16 mile diameter crater intruding on the western rim. Under grazing sunlight, several small craters can be made out in my 6 inch refractor on the floor. There is a tiny central hill and other small hills that can be seen under the low sun. Catch this example of a fine bay 5 days after new Moon. This is a good formation to show to guests at public observations.

Rosse (7 miles) is a small but very prominent crater out in the Sea of Nectar. It is about 1½ miles deep.

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© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Louisville Astronomical SocietyLouisvilleUSA

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