A Starry Calendar Part I - Lick Observatory

Jack Kramer

The night sky is a grand timepiece and calendar, and a neat way to tell a story. This was especially true among Native Americans. They carefully watched to see the first time certain stars could be seen in the pre-dawn sky and the last setting of the stars before they were in conjunction with the sun. This is known as a heliacal rising or setting. Much of their agriculture and ceremonials were based on these heliacal events. In addition, certain constellations held particular prominence for them.

The position of Orion in the sky was important to the Pueblo Indians for establishing the dates of various ceremonies. Early Native Americans referred to the rising belt stars as the "Spear" because it reminded them of a spear held aloft in a vertical position. On late fall evenings when Orion is rising, you'll note its belt stars form a vertical line low in the east (as in the illustration below). Watching these stars rise before dawn, early sky watchers knew the summer season was well along.

When Orion is low in the west during the evening hours of late spring, the belt stars are oriented about 90o from where they were nine months ago. They are then in an almost horizontal position with respect to the horizon.

We tend to think of the Pleiades as a cold weather cluster, because it's a familiar sight on winter evenings. However, in the summer if you stay up late observing, you'll realize just how long you've been out when you see the Pleiades low in the east. The Pleiades is one of those celestial star groupings that has served a calendrical function for many people since ancient times. The heliacal rising of the Pleiades signaled the opening of the navigation season on the Mediterranean. These stars were known by various names, but commonly as the "Seven Sisters" in many Old World cultures. Similarly, in the Western Hemisphere, the Kiowa Indians of Wyoming referred to them as the "Seven Maidens".

To the Navajo, the Pleiades was known as Dilyehe and was one of the groupings placed in the sky by their Black God, or Fire God. Legend says that when Black God entered the hogan of creation, he stamped his foot four times and Dilyehe eventually jumped to his left temple. So Navajo ceremonial masks that depict Black God have the figure of the Pleiades on the left temple.

Another reckoning point is culmination - which is when a celestial object reaches its highest point in the sky. When the Pleiades culminated at midnight, that set the time for the Celtic feast of Samain ("End of Summer"), one of the most important calendar festivals of the their year. The world of the gods was believed to be made visible to mankind, and the gods played tricks on their worshipers. It was a mystical time of danger and fear. It was also the dreaded witches' Sabbath and precursor of the Christian feast of All Hallows Eve (Halloween). In the Middle Ages, the Pleiades culminated at midnight on November 1st, but due to precession, it now culminates about November 21st. In Meso-America the time counts of two ancient Aztec and Mayan calendars coincided every 52 years at the midnight culmination of the Pleiades. They believed the world would end at one of these time count coincidences, one of which occurred a few years ago.

Anyone who is familiar with the night sky knows the season of the year merely by noting what constellations are up. Today when we're out under the stars, we glance at our watches to tell how late it's getting. But as scientifically astute as we may consider ourselves, the stars still work their calendar magic on us. Observers who stay up into the wee hours get a jump on the seasons; it's as if the sky projects us ahead in time to see the constellations that will be the evening sights of the following season. And those of us who pull an all-night observing stint see the near-circumpolar constellations as they set in the evening, then watch them rise again in the early morning hours.

It makes you appreciate why ancient peoples carefully watched the stars and had so many tales of mythical characters populating their sky.

For more star lore of ancient cultures, see Burnham's Celestial Handbook and/or Living the Sky, by Ray Williamson.

Published in the October 2004 issue of the NightTimes