Ancient star catalog found.
A treasure of ancient astronomy had long been considered lost, but last year a researcher realized that a representation of it has been in plain sight for centuries, in the form of a classical sculpture in Italy. The famous Farnese Atlas, a statue on display in Naples dating back to the 2nd century AD, depicts the mythological Titan bearing the weight of a celestial globe. The sphere is covered with figures of ancient Greek constellations.
According to Bradley E. Schaefer (Louisiana State University), vacationing in Naples when he saw the statue, the version of the heavens held by Atlas records the sky as observed by Hipparchus of Rhodes and represents the sole direct record of the world's first star catalog. Hipparchus lived in the 2nd century BC and had many pioneering mathematical and scientific achievements, among them a list of the positions of about 1,000 stars visible from the Mediterranean region. Although his constellation descriptions survived, a written version of his catalog did not.
Experts believe the sculpture is a copy of an earlier work. Historians have attempted to pin down a date that would link the original marble star map to the ancient sky, but results ranged from 1130 BC to AD 200. Besides the 41 mythological constellation figures, the globe also features important reference circles. These led Schaefer to calculate how much the sky has shifted due to Earth's wobble of precession (one of Hipparchus's own discoveries). Schaefer concludes that the Atlas shows the sky from 125 BC, give or take 55 years, which is when Hipparchus lived.
There's other supporting evidence, says Schaefer. Hipparchus's constellation descriptions perfectly match those on the Atlas globe. Although the carved figures are starless, the placement of their body parts for which stars are named is accurate to a few degrees. And Hipparchus was indeed known to have made globes from his catalog. Details of Schaefer's analysis appear in the May 2005 Journal for the History of Astronomy.
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|Author:||Goldman, Stuart J.|
|Publication:||Sky & Telescope|
|Date:||Jul 1, 2005|
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