AMHERST, Mass. – The public is invited to join University of Massachusetts 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, and will be streamed live from the center of the Sunwheel.
The UMass Sunwheel is a solar calendar made up of a stone circle, like England’s famous Stonehenge. Also like Stonehenge, the UMass Sunwheel’s standing stones mark the location of the rising and setting sun during equinoxes and solstices.
Each of this springs’s broadcasts will begin 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 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 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 the equinoctial sunrise and sunset this year. Visitors are welcome at other times and should wear masks and be prepared for especially wet footing. The UMass Amherst Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road, or Amity Street, about one-quarter mile west of University Drive.
The public webinar will be hosted on Zoom: https://umass-amherst.zoom.us/j/92907531333
For more information on the Sunwheel, visit the UMass Department of Astronomy’s homepage.