AMHERST — Residents of western Massachusetts are being invited to mark the winter solstice outdoors by gathering around the UMass-Amherst sunwheel.
The university has invited the public to assemble around the Stonehenge-like outdoor circle, whose standing stones line up with the locations on the horizon of the rising and setting sun at the times of the solstices and equinoxes.
The winter solstice marks the date when nights are longest and days are shortest in the Northern Hemisphere and the sun rises and sets at its most southerly location along the horizon.
Gatherings will be held at 7 a.m. and 3:30 p.m. on Dec. 21. UMass astronomers, who built the sunwheel, said the events will be canceled in the event of heavy rain or snow.
At the hour-long gatherings, UMass Amherst astronomers discuss the astronomical cause of the solstice. They explain the seasonal positions of Earth, the sun and moon, why the earliest sunset occurs about two weeks earlier and the latest sunrise about two weeks later, building the sunwheel and the design of other calendar sites such as Stonehenge and Chankillo.
They will also answer other astronomical questions. If it is clear, a solar telescope will be set up to safely observe the surface of the sun, and there may be an opportunity for a telescopic view of the gibbous moon at the evening session.
Even though the instant when the sun is most southerly occurs at 11:48 p.m. local time on Dec. 21, sunwheel visitors who stop in on their own will be able to see the sun rising and setting over the winter solstice stones from roughly Dec. 16–26. This is because at the solstice (which means stationary sun) the sun appears to rise at a fixed spot on the southeast horizon and to set in a fixed southwest direction for more than a week.
Teachers can earn certificates of participation for attending seasonal gatherings at the sunwheel. Contact Stephen Schneider at [email protected] for more information.
The UMass sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road (Amity St.) about one-quarter mile south of University Drive. Visitors to the sunwheel should be prepared for freezing temperatures and wet footing.
