Once again this year the public is being invited to echo the ancient custom of observing the annual winter solstice at the Okanagan’s own standing stone structure Pen Henge on Munson Mountain in Penticton.
The event, which marks the sun’s southernmost setting point, will take place on Saturday afternoon, Dec. 21 with interested people gathering around 3 p.m. in anticipation of sunset at 3:27 p.m.
The solstice gathering is being organized by the Penticton meeting group of the Okanagan Centre of the Royal Astronomical Society of Canada and they will provide preliminary information earlier in the day between 9 a.m. and 1 p.m. during the Farmer’s Market at the Shatford Centre, 760 Main St., Penticton. Coincidentally, the actual moment of winter solstice will occur at 9:11 a.m. PST.
If skies are clear, participants gathered at Munson Mountain will see the lengthening shadow cast by the sun over the winter solstice stone gradually extend toward the central heel stone.
At 3:27 p.m., the sun will set in perfect alignment with the two stones as befits the day of winter solstice when the sun reaches its most southerly point of the year.
Following the observance, OCRASC will invite solstice observers to return with them to the Shatford Centre for hot beverages and treats, and a chance to talk with members about the solstice or other astronomy related topics.
The Pen Henge standing stone array is a project spearheaded by Chris Purton and the Okanagan Astronomical Society which later became part of OC RASC, and which was supported by Penticton City Council and its Parks Department.
The installation, which is located at the top of Munson Mountain above the large Penticton sign on the east side of Okanagan Lake, consists of four stones that delineate the sunset points on the four cardinal dates of the year.
Anchored by the Heel Stone, the Equinox Stone points to the Sun’s sunset point at both the Spring and Fall Equinoxes, while the other two stones mark the Winter and Summer Solstice setting points respectively.
Photos of the array and earlier observances can be viewed on the OC RASC website at rascoc.zenfolio.com/p500357414.
Chris Purton, a retired scientist at the Dominion Radio Astrophysical Observatory at White Lake said, “For most of the year the structure simply illustrates the enormous range along the western horizon where the Sun sets. Most people subconsciously know of this, but they are quite fascinated to see the idea laid out so graphically.”
A brass plaque with a brief explanation of the array is permanently attached to the top of the heel stone.