Logo for Sunwheel Project


Sunwheel in Winter


Monday, March 20, 2023

  • 6:45 a.m. and 6:00 p.m. (EDT)

AMHERST, Mass. - The public is invited to view the sunrise and sunset on the day of the spring equinox among the standing stones of the University of Massachusetts Amherst's Sunwheel on Monday, March 20 at 6:45 a.m. and 6 p.m. These Sunwheel events mark the astronomical change of seasons when days and nights are nearly equal in length everywhere in the world, which is the source of the term equinox (for "equal night"), and UMass astronomers will give talks explaining the astronomy of the seasonal changes

Observers standing at the center of the Sunwheel's standing stones will see the sun rise and set over stones placed to mark the equinoxes, very close to due east and due west. Other structures around the world mark this astronomical change, such as the pyramid at Chichen Itza. The exact time of the equinox this year is 5:24 p.m. Eastern Daylight Time on March 20. This is the moment when the sun crosses the celestial equator, traveling from south to north as viewed from Earth.

On the equinox, observers at Earth's poles see the sun skimming around the entire horizon as six months of daylight begin at the North Pole and six months of night at the South Pole. Observers at the equator will see the sun pass directly overhead at local noon. After the March equinox, Earth's Northern Hemisphere tilts progressively more toward the sun.

During the approximately hour-long gatherings, UMass Amherst astronomer Stephen Schneider will discuss the astronomical cause of the Sun's changing position and how the Sunwheel helps track these motions. He will explain the seasonal positions of the sun, moon and Earth, and answer questions about astronomy.

Visitors to the Sunwheel should be prepared for especially wet footing this year. Rain or blizzard conditions cancel the events.

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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