September 5, 2004

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Lunar Super-Heroes


Image Credit: Cristian Fattinnanzi

Lunar Super-Heroes

The Olympics are over, but some Greek super heroes live forever. Two of the mightiest gods of ancient Greece were Atlas and Hercules. Atlas was so strong that he held the Earth and the heavens on his shoulders, and Hercules labored at so many trials (including holding the Earth for Atlas for awhile) that he would make the pentathlon look easy. On the Moon these heroes are still side by side. Atlas (87) and Hercules (69 km) started out as similar complex craters looking like Copernicus. Both maintain the scarp at their inner rim crest but have tired looking terraces which have lost their distinctiveness. The floors are where these heroic craters differ. Hercules is simple - mare basalts have flooded its interior, covering its original floor and central peaks except for some tiny nubbins. A more recent impact created the 13.8 km wide Hercules G on the south side of its floor. Atlas is more interesting but more difficult to see the features that make it so. Atlas is shallow and only the tops of its peaks are visible, but its floor is not lava covered. A family of mostly concentric rilles cut the floor and parts of the inner wall slopes. At high sun these two craters reveal more. The floor of Hercules is dark, as expected, but Atlas surprises with two dark halo craters - one on the northern inner wall and the other on the south wall. These are explosive volcanic deposits similar to those along the rilles of Alphonsus. Atlas is another floor-fractured crater.

Chuck Wood

Technical Details:
Sept 2, 2004. Newtonian telescope of 25 cm (10") aperture and about 7.5 m focal length; sum of 200 frames from 300 acquired using Iris.

Related Links:
Hercules in myth
Lunar Orbiter IV View Hercules
Lunar Orbiter IV View Atlas
CLA High Sun Image
Rukl Atlas of the Moon Sheets 14 & 15

Yesterday's LPOD: ToolKit Disc

Tomorrow's LPOD: Terrific Taruntius


Author & Editor:
Charles A. Wood


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