Borrowed from Astronomy Magazine Newsletter 9/26 received by Email
Aries the Ram certainly never stepped on the Moon, but it's fun to imagine that it left a large hoofprint on the lunar surface. By the evening of October 6, the Sun has risen over the fascinating Hyginus, Triesnecker, and Ariadaeus rille complexes. Yet, one thing that catches the eye in this area just north of the lunar equator is the delightful "Aries' hoofprint" feature. The combination of brightly lit mountains and two deep channels of dark lava creates this striking play of light and shade.
It's easy to understand why lunar maps don't label this feature -- physically, it's a jumble of mountains left over from the giant Imbrium impact, with a channel of large, dark plains on either side.
Lunar scientists focus with good reason on the fascinating Hyginus Rille because it almost surely formed from volcanic activity long ago. But at low power with the whole lunar disk in view, the Aries' hoofprint stands out.
Hyginus Crater is a huge collapse pit, the biggest in a chain of smaller pits that sculpt the edges of a long-ago lava channel. The crater spans 6.6 miles and has walls more than 2,000 feet high. It stands out nicely as the Sun rises because one wall lies in bright sunlight while the other remains in shadow.
Within just 24 hours, the Aries' hoofprint and the Hyginus Rille become mere echoes of their sunrise magnificence. By October 8, they'll have gone into hiding under the Sun's increasing glare.
To find more observable objects in your sky, visit Astronomy.com's sky events calender here.
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Terri, Events Coordinator
Email: Events@PASAz.org
Phoenix Astronomical Society
