Sumerian Star Chart Recreation (plaster cast). About 5 3/8 inches round. A recreation of a Sumerian star map or "planisphere" recovered from the 650BC underground library of Ashurbanipal in Nineveh, Iraq in the late 19th century. Long thought to be an Assyrian tablet, computer analysis has matched it with the sky above Mesopotamia in 3300BC and proves it to be of much more ancient Sumerian origin. The tablet is an "Astrolabe", the earliest known astronomical instrument. It usually consisted of a segmented, disc shaped star chart with marked units of angle measure inscribed upon the rim. Unfortunately considerable parts of the planisphere are missing ( approx 40%), damage which dates to the sacking of Nineveh. The reverse of the tablet is not inscribed. Some call this the Sodom and Gomorrah Tablet because it describes a comet/asteroid which some think destroyed Sodom and Gomorrah about 3300 BC. For more information see Alan Bond and Mark Hempsell's book about this tablet called "A Sumerian Observation of the Kofels' Impact Event." published in 2008.