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Octagon Moon Rise at Newark Earthworks

Ancient Observatory of the Ohio Hopewell


Octagon Moon Rise

Poster from the Octagon Moon Rise, an event celebrating the ancient lunar observatory of the Ohio Hopewell civilization

Ohio State Historical Society
During the fall of 2005, the Newark Earthworks, the “solid state lunar computer” of the Hopewell civilization, will mark the northern-most track of the earth’s moon at the end of its lunar cycle. The Octagon Moon Rise of October 22, 2005, as the event has been called by organizers, is an excellent opportunity to watch the nearly full moon rise using an ancient observatory built in the Licking River valley of Ohio some 2000 years ago.

The Hopewell civilization is the name archaeologists have given to people who lived in what is now most of the American middle west, along major rivers of Tennessee, Ohio, Indiana, Kentucky and Illinois, from about 200 BC to 400 AD. Like many other Middle Woodland societies, the Hopewell were part time farmers, who lived in villages. The Hopewell had access to a wide set of trade goods and exotic materials from a region encompassing the Gulf Coast to the Great Lakes, and many of these trade goods ended up in burials and charnel houses. But the truly awe-inspiring characteristic about the Hopewell is their monumental architecture, consisting primarily of earthen enclosures, large open spaces encircled by tall rammed earth and stone walls. The largest of these earthworks is called Newark, after the nearby town of Newark, Ohio, on a high glacial terrace of the Licking River. The Newark Earthwork complex covers an area of four square miles, and at one time included six large enclosures, hundreds of mounds and smaller enclosures, and portions of what archaeologists call the Great Hopewell Road, connecting the largest enclosures and perhaps other settlements of the Hopewell culture.

Enclosures at Newark Earthworks

The enclosures at Newark included the Great Circle, 366 meters in diameter, with walls up to 5 meters high enclosing an area of 30 acres. The Great Circle is largely intact because it was used for the Licking County fair between 1854 and 1933. The Cherry Valley Mounds is the name given to about a dozen mounds in the middle of an oval enclosure, about 550 meters across. The mounds themselves contained several human burials with deluxe grave goods, including sheets of mica between one-half and one inch in thickness. Unfortunately, the Cherry Valley Mounds, located at the east edge of the earthworks have been largely destroyed by the urban expansion of the city of Newark. The Salisbury Square measured 226x232 meters and was located on the east bank of the Licking River; little is known about it, because it too disappeared under the city streets of Newark, although it is known to have held several artifact caches. The Wright Earthworks consists of a rectangle of 285x290 meters square, enclosing about 20 acres.

The main group of enclosures at Newark, all more or less intact and located within a golf course in the city of Newark, includes the Observatory Circle and Octagon, and portions of the Great Hopewell Road. It is this collection of enclosures that was apparently constructed in part to act as a lunar observatory, with walls and alignments set to track the path of the moonrise and set as it changes throughout its 18.6 year cycle. The Observatory Circle is 320 meters in diameter, with walls of about 1.5 to 2 meters in height. The adjoining Octagon has eight sides, each wall built along on an alignment of the rising or setting moon during the lunar cycle. The Hopewell Road connects these buildings, and then extends to the southwest from the Observatory Circle; it consists of two parallel walls 60 meters apart, each one meter high.

Moon Rise at the Newark Earthworks

At a few times throughout the fall of 2005, one can stand on the Observatory mound at the west edge of the Observatory Circle, and look across and through the parallel walls leading into the Octagon and watch the moon rise along the main axis of these conjoined earthworks. The public celebration of the Octagon Moon Rise event has been scheduled for 10:14 pm on October 22, 2005.


The website assembled for the Octagon Moon Rise event has much more detailed information concerning the event, the archaeology of the Newark Earthworks, the astronomy of the 18.6 year lunar cycle, and symposiums scheduled for the fall.

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