October 27, 2017

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A Little Archimedes

Originally published April 18, 2008 LPOD-Apr18-08.jpg
images by Damian Peach (south up)

I have always been drawn to Cassini even though there is not much dramatically interesting there. With its wreath of ejecta overlapped by Imbrium lavas, narrow rim and smooth floor it reminds me of a little Archimedes. But its not a perfect match - the rim is narrow, like Gambarts, and the smoothness of the floor is marred by two large craters and almost a quadrant of roughness. The bend in Cassini's rim to the east (left in these south up images) suggests that a rim collapse may have deposited some of the nearby roughness on the crater floor. Alternatively, the two segments of rilles may imply that the crater originally had an inner concentric hilly ring and was a floor-fractured crater. FFCs are lifted up by rising magma beneath their floors, but it seems unlikely that a solidified uplifted floor would subside to be lost from view except in one quadrant. Another perplexing inner feature is the elongated crater Cassini A. I wonder if this is actually two craters that formed simultaneously from two closely spaced projections - a binary asteroid? Damian's two views show that there are two distinct radii of curvatures, with the wall join between them being very smooth. The high Sun view shows that the floor is at two levels, with the smaller side being higher. So perhaps the elongated shape is simply due to a massive landslide, creating a mega-scallop in the rim, and dumping a pile of debris on the floor.

Chuck Wood

Technical Details
2006/04/19 & 2005/09/22. C14 @ F41. LU075M

Related Links
Rükl plate 12
Damian's lunar web pages (hopefully the Barbados lunar images from 2007 are coming soon!)

Yesterday's LPOD: Petavian View

Tomorrow's LPOD: New Mysteries in Familiar Territory


1) Aaaaaaaah, my Cassini! Thank you Damian and Chuck! Cassini was the spark that trigured my love for the Moon. It was a litle foto 2x3 cm with Vallis Alpes and Cassini. And it was just 4 years ago! I just had to find out what is the name of beautifull crater with smaler craters in it! And than the awalanch trigered and now am on the Moon every day (net) and every clear night. Bless the internet so I can met u all, Moonlover and Lunatics.
Have a great weekend all of you.
Aleksander Božič, Slovenia
PS - Chuch, next week I have my first speach for the Slovenian astrophotografers. They all know Messiers objects, but know nothing of your Lunar 100. And all of them don't like the Moon very much hehe it spoils their deepsky fotos :) Am honored that I can be the first to present your beautifull contribution to Moon observing to Slovenian astronomers. And also C14 for video projection of the Moon will be on for me to show the objects of 20 day old Moon LIVE ! :) Some good weather wishes from your side needed for the 25th-26th April. Thanky you ;)

2) Aleksander - When I talk to astronomy groups there are usually none who observe the Moon. I kid them, but am serious, that they spend their time trying to spot a smudge of light with almost no detail. But right next door is the only place in the universe where we can observe in great detail an entire world. And we can learn not just a few craters' names but also can learn to read its history, making it fabulously more interesting. By the end of my talks I try to get them cursing the few nights when the Moon is NOT in the sky!
I wish you good luck - and clear sky - for your talk! Tell them that I invite them to visit LPOD and the Moon Wiki, but more importantly, to learn to love their cosmic neighbor.


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