Sherman, Texas—The 2022 Fall Equinox will arrive in Sherman on Thursday, September 22, at solar noon, 1:19 p.m. CDT.  

For most, the moment likely will pass unnoticed. Austin College physicist David Baker is preparing once again to demonstrate the workings of the unique Gnomon Hole in the roof of the College’s IDEA Center. The Gnomon Hole creates a solar observatory that Baker says is the only one of its kind on a U.S. college campus.

To mark the event, the public is invited to join faculty, staff, and students, at no charge, for the Equinox event from 1 p.m. to 1:20 in the Oscar C. Page Atrium of the IDEA Center. The IDEA Center is located on the Austin College campus at 1108 E. Richards Street. Sunlight is required for the event so rain or overcast conditions will mean cancellation of the event. 

The IDEA Center itself serves as a large astronomical observatory that displays the movement of the Sun across the building’s atrium. Sunlight passes through the Gnomon Hole in the roof to cast an image on the atrium floor. The atrium was constructed so that, at solar noon, the sunbeams of the autumn and spring equinoxes fall on the Chinese symbol for the Sun in recognition of Asian contributions to knowledge of the universe.

 “Watching the sunbeam march across the floor of the Page Atrium and arrive at the equinox marker is magical,” said Baker. “The magic moment occurs at ‘solar noon,’ 1:19 p.m. CDT. The solar observatory at Austin College does this is a unique way. It is worth seeing.”

Baker will provide a historical and scientific overview during the event. A Gnomon Hole is an ancient device originally used to compute time.

 The summer solstice is marked by the Greek/Macedonian symbol for the Sun to symbolize the contributions of the West in the understanding of the universe, and the winter solstice, marked by the Mayan symbol, recognizes Native American contributions.