Winter Solstice Sunrise and Sunset Sky-Watching at the UMass Sunwheel
December 21, 2018
UMass Amherst Campus
The public is invited to witness sunrise and sunset among the tall standing stones of the UMass Amherst Sunwheel on the day of the winter solstice, Friday, Dec. 21, at 7 a.m. and 3:30 p.m. Heavy rain or snow will cancel the gatherings.
At the hour-long Sunwheel events, UMass astronomer Stephen Schneider will explain why the sun rises and sets at its most southerly position on this day of the year. He will also explain the seasonal positions of the Earth, the sun and moon, and the design of the Sunwheel and other archaeological sites built to mark this day, such as the Temple of Karnak in Egypt and Chankillo in Peru.
The sun reaches its southernmost position relative to the stars at 5:23 p.m. local time on Dec. 21, marking the astronomical change of seasons. The day of the winter solstice is also when night is longest and day is shortest in the Northern Hemisphere, while the reverse is true in the Southern Hemisphere.
If it is clear at sunrise there will be an opportunity to view the “morning star” Venus and at sunset the rising of the nearly full moon. At the evening session, a solar telescope will be set up to safely observe the surface of the sun before it sets.
Though the time between sunrise and sunset is shortest on Dec. 21, the earliest sunset occurs about two weeks before the solstice and the latest sunrise about two weeks later. This is because Earth is closer to the sun this time of year than it is in northern summer, a situation Schneider will discuss with other celestial phenomena.
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. 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, which is how the solstice (which means stationary sun) got its name.
Visitors to the Sunwheel should be prepared for freezing temperatures and wet footing.
The UMass Amherst Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road (Amity St.) about one-quarter mile south of University Drive.