Ceremony marks autumn equinox

Residents are invited to usher in fall at the Pen Henge standing stone array on top of Munson Mountain on Thursday.

Residents are invited to usher in fall at the Pen Henge standing stone array on top of Munson Mountain on Thursday.

Although the actual time of the fall equinox will be 2:05 a.m. Friday, the gathering will take place  the evening before. Participants are invited to arrive after 5:45 p.m. to prepare for the sunset at about 6:20 p.m.

Members of the Okanagan Centre of the Royal Astronomical Society of Canada have set up a display to help explain the significance of the equinox and the sun’s annual northward and southward migrations.

The standing stone array is made up of four stones; a heel stone to the east, and three other stones which mark the sunset direction at the summer and winter solstice, and the spring and fall equinox. At those times the sun’s shadow extends from the respective marker stones directly to the heel stone.

“For most of the year the structure simply illustrates the enormous range along the western horizon where the sun sets,” said Chris Purton, who spearheaded the Pen Henge project. “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 was dedicated in December and is now permanently attached to the top of the heel stone. The array is located at the top of Munson Mountain directly above the ‘Penticton’ sign, and it is reached by a pathway leading up from the parking lot in the park.

The Okanagan Centre of the Royal Astronomical Society of Canada has over 110 members extending from Osoyoos to Salmon Arm. Interested members of the public are welcome to attend regular OC RASC meetings which take place on the first Tuesday of the month in Kelowna, on the first Thursday in Penticton and on the last Wednesday in Vernon. Meeting details can be found on the club’s website www.ocrasc.ca.

The organization operates the Okanagan Observatory which is located on the Big White Road west of Kelowna. Free public viewing as well as a free audio visual presentation are offered on clear Friday evenings at the observatory. The public evenings can be confirmed by calling 250-300-8759 after 3 p.m. every Friday. Actual observing is offered through member telescopes as well as the Observatory’s own 25-inch reflecting telescope.