Winter Solstice at the UMass Amherst Sunwheel Offers Webinars on Dec. 21, Urges Individual Visits

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AMHERST, Mass. – To mark the sun reaching its southerly extreme and the start of astronomical winter, astronomers at the University of Massachusetts Amherst will give live presentations via webinar from the campus’s unique Sunwheel at 7:15 a.m. and 3:45 p.m. on Monday, Dec. 21. The online sessions are free and open to the public.

Interested people are also invited to visit the Sunwheel to observe sunrise and sunset on their own in the days preceding and following the official solstice.

During the webinar, UMass Amherst astronomer Stephen Schneider will discuss the astronomical cause of the solstice, and a live video feed will show the sunrise and sunset alignments, weather permitting. He will be joined by other astronomers online to help answer questions, explain the seasonal positions of Earth, sun and moon, and the design of the Sunwheel.

On the day of the winter solstice, Earth’s North Pole is tilted farthest away from the sun, causing the shortest day and longest night of the year in the Northern Hemisphere. On this date the sun rises over the southeasterly standing stone and sets over the southwesterly stone in the Sunwheel, and daylight will last about 9 hours 4 ½ minutes in Amherst. The sun actually reaches its southernmost position as seen from Earth at 5:02 a.m. EST on Dec. 21, and then begins moving northward.

At the summer and winter solstices, literally meaning “stationary sun,” the sun barely appears to shift north or south for more than a week. As a result, the length of day and the sunrise and sunset positions remain so nearly the same that it would require high-precision instruments to detect the changes.

The duration of daylight changes by less than 30 seconds from Dec. 17 to 23, which is a period when the ancient Roman solstice festival of Saturnalia was held. Visitors can view nearly the identical sunrise and sunset alignments from the Sunwheel from five days before to five days after the day of the solstice on a day with good viewing weather. Sunwheel astronomers do request that visitors wear a mask and select days other than Dec. 21, the day of the live broadcast.

Another special and unusual astronomical event will be featured in this month’s webinar. Schneider and colleagues will provide tips on observing the close conjunction of Jupiter and Saturn on the evening of the solstice, Dec. 21. It will be the closest visible alignment of these two planets in almost 800 years, he points out.

The UMass Amherst Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road (Amity St.) about one-quarter mile the Sunwheel is about 1/4 mile west of University Drive. Visitors to the Sunwheel should be prepared for freezing temperatures and wet footing, and they should wear masks.