Spring Equinox Sky-Watching Events at the UMass Sunwheel
March 20, 2019
UMass Amherst Campus
View the sunrise and sunset on the spring equinox among the standing stones of the UMass Amherst Sunwheel at 6:45 a.m. and 6 p.m.
This marks the astronomical change of seasons when days and nights are nearly equal in length in the Northern Hemisphere.
At the hour-long gatherings, UMass Amherst astronomer Stephen Schneider will discuss the astronomical cause of the sun’s changing position. He will explain the seasonal positions of the sun, moon and Earth, and answer questions about astronomy. On the equinox (for equi, “equal” and nox, “night”) the sun rises due east and sets due west and stays up for 12 hours and down for 12 hours almost everywhere in the world. 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.
The exact time of the spring or vernal equinox in western Massachusetts this year is at 5:58 p.m. on March 20. This marks the moment when the sun crosses the celestial equator, traveling from south to north. An observer located on the Earth’s equator will see the sun pass directly overhead at local noon on this day. After the spring equinox, Earth’s Northern Hemisphere is tilted toward the sun.
If the skies are clear during the evening session, a solar telescope will be set up to safely observe the sun before sunset. The full “sap” or “worm” moon will rise just minutes after sunset almost exactly due east. Names for the full moons come from cultural and natural events at that time of year, such as the running of sap or the emergence of worms from the thawing ground.
Visitors to the Sunwheel should be prepared for especially wet footing this year. Rain or blizzard conditions cancel the events.
The UMass Amherst Sunwheel is located south of McGuirk Alumni Stadium, just off Rocky Hill Road (Amity St.) about one-quarter mile south of University Drive.