Observe Rare Transit of Venus on June 5 at UMass Amherst Sunwheel

AMHERST, Mass. - The public is invited to witness one of the rarest of astronomical events, a transit of Venus, at the University of Massachusetts Amherst Sunwheel from 5:30 p.m. until sunset on Tuesday, June 5.

Astronomy professor and department chair Stephen Schneider will introduce the transit and the Sunwheel. During the transit, which is similar to an eclipse except that Venus is so far away it only blocks a small part of the sun, observers can see Venus as a small disk moving across the sun. The actual transit begins at 6:04 p.m. and visitors may watch until sunset at 8:23. Rain cancels the event, but light clouds will not.

"Transits are extremely rare because the sun, Venus and Earth have to be in almost perfect alignment," says Schneider. "Venus passes by Earth every 19 months as it orbits the sun, but in all the conjunctions for the next 105 years, Venus will miss to the north or south of the sun from our vantage point on Earth, so it will pass by unseen. An observable transit won’t happen again until 2117. I’m delighted to share our excitement about astronomy and help everyone to observe this event safely."

Schneider reminds amateur astronomers that it is never safe to look directly at the sun, especially through binoculars or telescopes, without using special solar light filters to protect the eyes. Photographic film is not safe and will not prevent damage to the retina. "We will have telescopes set up to project the image of the sun for safe viewing, along with a solar telescope and special glasses that visitors can use to observe safely," he notes.

The astronomer recalls that transits of Venus were made famous by Sir Edmund Halley of Halley’s Comet fame, who showed that carefully timing the transits from widely separated spots on earth could be used to accurately measure the distance to Venus and the sun for the first time. This led astronomers Mason and Dixon, famous for surveying a line that became important in United States history, to brave naval warfare to travel to Cape of Good Hope in 1761 to make some of the first accurate measurements.

Before the 1761 transit, the sun’s distance was very uncertain and estimates of the size and distance of objects in the solar system were greatly underestimated. Transit observations also provided the first evidence that Venus has an atmosphere. The Kepler satellite now in orbit will provide modern researchers with more fascinating data from this year’s transit.

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.