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Sunwheel in Winter


  • Tuesday, September 22, 2020
  • 6:30 a.m. and 6:15 p.m. (EDT)
  • To join the webinar broadcast, click here.
    If you don't have Zoom on your device, there's a link on the page to download it. Give yourself a few extra minutes to install it.
    Looking forward to seeing you there!
    ---Steve Schneider
  • Video of sunrise presentation from the Sunwheel: click here
    Video of sunset presentation from the Sunwheel: click here

The public is invited to observe sunrise and sunset virtually on the day of the autumnal equinox among the standing stones of the UMass Amherst Sunwheel on Tuesday, Sept. 22 at 6:30 a.m. and 6:15 p.m. Weather permitting, the sun will be observed as it rises and sets over the eastern and western standing stones of the Sunwheel. This marks the change of seasons when days and nights are nearly equal in length around the world.

UMass Amherst astronomer Stephen Schneider will discuss via a web broadcast the astronomical cause of the sun's changing position during the live presentation. He will also explain the design and history of the Sunwheel, and how it marks the changing positions of the sun and moon.

The precise astronomical time of the autumnal equinox this year is 9:30 a.m. Eastern Daylight Time on Sept. 22. This marks the moment when the sun crosses the celestial equator from north to south as seen from Earth, ushering in the beginning of fall in the Northern Hemisphere and spring in the Southern Hemisphere. On the day of the equinox, an observer located on Earth's equator will see the sun pass directly overhead at local noon, and it marks the beginning of six months of daylight at the South Pole and six months of nighttime at the North Pole. On any day other than the equinox, either the Earth's Northern or Southern Hemisphere is tilted toward the sun.

On the equinox (for equi, "equal" and nox, "night") the sun very nearly rises due east and sets due west and stays up for 12 hours and down for 12 hours, except as seen from the North and South Poles, where the sun circles the sky, skimming the horizon. From the Sunwheel in Amherst, observers standing at the center of the standing stones see the sun rise and set over stones placed to mark the equinoxes.

To share this event while avoiding crowds during this time of the pandemic, the Sunwheel will not be open to the public during these broadcasts. Details of joining Prof. Schneider online live will be posted on the Astronomy Department's website at www.astro.umass.edu and the Sunwheel website at www.umass.edu/sunwheel by the day before the event.


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


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