AMHERST, Mass. – The public is invited to join UMass Amherst astronomers Judith Young and Steve Schneider to witness sunrise and sunset associated with the summer solstice among the standing stones of the UMass Amherst Sunwheel on Wednesday, June 20 at 5 a.m. and 7:30 p.m. Rain cancels the events.
These Sunwheel events mark the astronomical change of season in the northern hemisphere when days are longest and nights are shortest.
At these hour-long gatherings, there will be a talk on the astronomical cause of the sun’s solstice or standstill. She also explains the seasonal positions of Earth, the sun and moon, phases of the moon, building the Sunwheel, and other calendar sites such as Stonehenge in England and Chichen Itza in Mexico. She will explain the moon’s 18.6-year cycle known as the Major Lunar Standstill and answer questions about astronomical signs of the seasons.
The solstice or standstill refers to the fact that the sun appears to rise at a fixed spot on the northeast horizon for more than a week, as marked by the tallest stones in the Sunwheel, and to set in a fixed northwest direction. Although the instant when the sun is most northerly occurs on June 20 at 7:09 p.m., people who visit the Sunwheel between about June 15 to 25 can witness the sunrise and sunset over the summer solstice stones.
The astronomical cause of the sun’s standstill is one of the topics to be explained during the June 20 gathering. The solstice also marks the time when any observer located on the Tropic of Cancer (latitude +23.5°) will see the sun pass directly overhead at local noon, when they will cast no shadow.
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. Visitors to the Sunwheel should be prepared for wet footing and mosquitoes, as well as cool temperature after sunset. A $3 donation is requested to help with the cost of the additional site work and future events.
All 2012 Sunwheel events: www.astro.umass.edu/~young/gatherings.html