Logo for Sunwheel Project


Sunwheel in Winter


Saturday, March 20, 2021

  • 7:00 a.m. and 6:30 p.m. (EDT)
  • We had some techniZoom problems during the morning broadcast so we don't have a recording.
  • Video of the equinox sunset presentation from the Sunwheel: click here

The public is invited to join UMass Amherst astronomers for live broadcasts from the Sunwheel on Saturday, March 20, the first day of spring. The webinar-format broadcasts will begin at 7 a.m. for sunrise and 6:30 p.m. for sunset streamed live from the center of the Sunwheel.

Each broadcast begins with a twenty-minute introduction to the UMass Sunwheel, followed by an opportunity, weather permitting, to see the alignment as the sun rises and sets against the Sunwheel’s tall standing stones. This unique calendar circle was designed by the late UMass professor of astronomy Judith Young, and has hosted public events celebrating the change of seasons since 1997.

During the presentations, Prof. Stephen Schneider will explain the changing positions of the sun, moon, and Earth, and how the standing stones of the Sunwheel act as a calendar to mark the start of each season. He and other UMass astronomers at the webinar will be available to answer questions about the Sunwheel as well as other questions about astronomy.

On the day of the March equinox, the sun crosses the celestial equator, passing from the southern to the northern half of the sky. This year, the crossing occurs at 5:37 a.m. EDT, which marks the astronomical start of spring in the Northern Hemisphere and the start of autumn in the Southern Hemisphere. On this date, the length of day and night are nearly equal, which gives us the term equi-nox or equal-night.

On the equinoxes, the sun rises nearly due east and sets nearly due west everywhere on Earth except close to the poles. At the North Pole, this date marks the start of 6 months of sunshine, and at the South Pole, 6 months of night. At both locations the sun skims all 360 degrees of the horizon over a 24-hour period.

Because of the COVID pandemic, the public is asked not to come to the Sunwheel during sunrise and sunset this year to aid us in broadcasting the event. Visitors are welcome at other times and should wear masks and be prepared for especially wet footing this time of year. Check for last-minute announcements on the main Sunwheel web page.

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 UMass 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

Go back button