AMHERST, Mass. – The public is invited to celebrate the beginning of spring and to view several celestial sights at the UMass Amherst Sunwheel on Thursday, March 19. In addition to the accustomed talks at 6:45 a.m. and 6 p.m. at sunrise and sunset among the standing stones, UMass Amherst astronomers will offer telescope views of the moon and planets beginning at about 6 a.m. and 7:30 p.m., weather permitting.
At the hour-long presentations for sunrise and sunset, UMass Amherst astronomer Stephen Schneider will explain the seasonal positions of the sun, moon, and Earth, why the Gregorian calendar system we use results in changing dates for the equinox, and answer other questions about astronomy.
On the day of the March equinox, the sun crosses the celestial equator, passing from the Southern to the Northern Hemisphere. Schneider says that this year, the crossing occurs just before midnight, at 11:49 p.m. in the eastern time zone on March 19 – making this the first time in 124 years that the date of the equinox has been so early here. The earlier date this year reflects the accumulation of small differences between the length of the year and the 365-and-one-quarter days that the Leap-year system is based upon.
On the equinox, the length of day and night are nearly equal, which gives us the term equi-nox or equal-night, he explains. Also, the sun rises due east and sets due west. The March equinox marks the astronomical start of spring in the Northern Hemisphere and fall in the Southern Hemisphere.
Schneider says if the sky is clear, there will be an opportunity before dawn to see a pretty grouping of the waning crescent moon, Jupiter, Saturn, and Mars low in the eastern sky. Jupiter and Mars will be very near each other, close to astronomical conjunction.
Then about one half-hour after the sunset presentation, the sky will be dark enough to view Venus, which will be close to half full and near its largest angular separation from the sun – known as its “greatest elongation.” The astronomer says, “We can also take a look at the star Betelgeuse, which has been behaving strangely over the past few months.” Before sunset, during the evening presentation, a solar telescope will also be set up to safely observe the surface of the sun.
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. Visitors to the Sunwheel should be prepared for especially wet footing this year. Rain or blizzard conditions cancel the events. Check for cancellation announcements on the Sunwheel website at www.umass.edu/sunwheel.