Photo: RASC-OC

The longest day of the year is just a few days away, and to celebrate, a gathering will take place at the "Pen Henge" standing stone array atop Penticton's Munson Mountain.

On June 21, the sun will set at its northernmost post on the horizon for this year. From 8 to 9 p.m., the public is invited to gather on Munson for a viewing organized by the Royal Astronomical Society of Canada and radio astronomer Chris Purton.

At approximately 8:50 p.m., the sun will set over the mountains to the west of Penticton, and if the sky is clear, its last rays of the evening will cast a shadow from the northernmost stone in the array, known as the Summer Summer Solstice Stone, toward the central Heel Stone.

The Pen Henge array was spearheaded by Purton, who is retired from the Dominion Radio Astrophysical Observatory at White Lake. The project consists of four stones that delineate the sunset points on the equinoxes and solstices throughout the year.

Careful measurements have led to the determination that the Pen Henge sunset will be at 8:50 p.m. The actual moment of the solstice this year, however, is 3:07 a.m on June 21. Purton explains that the moment of solstice comes roughly six hours later each year, time which is adjusted for by adding a leap day every four years, keeping the solstice around the 21st. 

Another solstice event will also be taking place, this one at Marina Way park and intended to celebrate people's connections to their environment. There will be singers, dancers and drummers, and the public is encouraged to bring a blanket to sit on and a drum or rattle to play along. 

The Prague Cafe will have pastries and beverages available to purchase, and the event begins at 6:30 p.m.