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Sunwheel in Winter


  • December 21
  • 7:15 a.m. and 3:45 p.m. (EST)
  • To join webinar click here
  • Video of sunrise presentation from the Sunwheel: click here
  • Video of sunset presentation from the Sunwheel: click here

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 public is 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 1/2 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 5 days before to 5 days after the day of the solstice, picking a day with good weather during that period. It is requested that visitors select days other than the day of the live broadcast, Dec. 21st, and that they wear masks.

Another special astronomical event will be featured in this month's webinar. Schneider and colleagues will provide tips on observing the close conjunction of Jupiter and Saturday 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.

Location: The UMass Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road. The Sunwheel can easily be reached from the center of Amherst, following Amity St. to the west, on the right hand side of the road about 1/4 mile after crossing University Drive.

More Information: For more information on the U.Mass. Sunwheel, click here. For more information on the Moon's 18.6-year cycle, click here.


For directions from out of town, click here.

For a map showing the Sunwheel on the UMass Amherst campus, click here.


For the dates and times of Sunwheel gatherings, click here.

  A project conceived by Dr. Judith S. Young
 Professor of Astronomy, University of Massachusetts, Amherst
 e-mail: Steve Schneider

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