StarDate

First Glimpse


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For most American skywatchers, the star Capella is just peeking into view in the morning twilight. It’s bright, but it’s quite low as the sky brightens. You need precise timing and a clear north-northeastern horizon to spot it.

A star’s first appearance is called the heliacal rising – a term that means “with the Sun.” It takes place at the same time every year, as the Sun completes a full circuit through the background of stars.

In many ancient cultures, the heliacal rising of certain stars was crucial. The best example is Sirius, the brightest star in the night sky. In Egypt, it first appeared just before the annual flooding of the Nile – the most important event of the year. So the star’s return marked the start of a new year.

Several cultures looked for the Pleiades star cluster. Its appearance marked a time to plant crops, or to gather them, depending on a culture’s location.

Capella might have been important to the Zapotec, who lived in present-day Mexico. A half-century ago, researchers proposed that a building in the city of Monte Albá‡n was intentionally aligned at a right angle to Capella’s rising point. The star first appeared there at the time the Sun passed directly overhead at noon – a key date in the calendar. But later work disputed that finding.

Capella isn’t nearly as important in modern times. But it reminds us that the stars once held great power over much of everyday life.

Script by Damond Benningfield

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StarDateBy Billy Henry

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