Rare lunar alignment returns to Chimney Rock after 18 years

DURANGO, Colo. — Every 18 to 19 years, the moon rises exactly between Chimney Rock and Companion Rock at Chimney Rock National Monument in Archuleta County, Colorado.

This short-lived celestial spectacle, when the moon reaches the extremes of its orbit, is known as a lunar standstill.

Many scholars believe the Ancient Puebloan people who built ceremonial spaces at Chimney Rock more than 1,000 years ago designed them to view this rare alignment.

During the last lunar standstill in the mid-2000s, the U.S. Forest Service allowed small groups to observe the event from a nearby fire tower. The tower was removed in 2010.

This year’s event is a partnership between the U.S. Forest Service, its tribal advisors, Fiske Planetarium at the University of Colorado, Griffith Observatory and the Chimney Rock Interpretive Association.

The next viewing events are set for September 13 and 14 at the monument’s amphitheater, with a live broadcast from Griffith Observatory. Another event will take place October 11.

After this year’s event, the lunar standstill won’t be visible again for another 18 years.