Transit of Venus, 1639-2012
Exhibition, Second Floor Gallery, Philosophical Hall
June 1 – 10 (see hours above)
This exhibition will document all observed Transits of Venus beginning in 1639 through images, rare books, and manuscripts, and will tell the story of the American Philosophical Society’s role in the 1769 Transit. It will feature three 18th-century instruments used to chart that event, including the Transit telescope and astronomical clock David Rittenhouse built for himself.

Portrait of David Rittenhouse and Rittenhouse’s Astronomical Transit Telescope

The Astronomer Collapses
A theatrical performance inspired by the Transit of Venus
Performance, APS Jefferson Garden (5th St. b/w Chestnut and Walnut Sts.)
Fri. June 1 (noon); Sat. & Sun., June 2 & 3 (11 a.m. & 3 p.m.); Mon. & Tues., June 4 & 5 (noon & 5 p.m.)
Join us for whimsical, drop-in performances about the Transit of Venus by playwright, director, and theater artist Aaron Cromie.

Chasing Venus: The Race to Measure the Heavens
Lecture and Book Signing, Benjamin Franklin Hall
Fri., June 1 (6 p.m.)
Author Andrea Wulf will present an illustrated lecture based on her forthcoming book on the history of the Transit of Venus. Her preceding book was Founding Gardeners: The Revolutionary Generation, Nature, and the Shaping of the American Nation, published in spring 2011.
Please rsvp for lecture to rsvpmuseum@amphilsoc.org

Transit Tune-Up: Waiting for Venus
A Family-Friendly Weekend in and around the APS and INHP
Sat. & Sun., June 2 & 3 (10 a.m. – 4 p.m.)
• Transit talk and science activities led by Derrick Pitts, Chief Astronomer at the Franklin Institute
• Surveying demonstrations by the Department of the Geographer to the Army (the recreated mapmaking unit of General Washington’s Continental Army Staff)
• Show-and-tell of surveying instruments with instrument maker and restorer Jeffrey Lock
• Transit insights with INHP guide Michael Doveton at Theater Two of the Independence Visitor Center
• Theatrical performance inspired by the Transit of Venus
Register for either day at rsvpmuseum@amphilsoc.org

SPECIAL OPPORTUNITY: TRANSIT OF VENUS VIEWING
Second Floor Gallery, Philosophical Hall
Tues., June 5 (6:03 p.m. – 9:26 p.m.)
Starting at 6:03 p.m., a live feed of the Transit from various points around the world will be broadcast in Philosophical Hall, as it will be difficult to observe in the city. The broadcast will continue until 9:26 p.m., when Venus will reach the midpoint of its passage across the sun.

This is an illustration of the Transit of Venus by Martin J. Powell. Click on the illustration to see the animated version on Powell’s website. Watch closely. It does move, but very slowly; it takes five minutes to complete the transit.

Other Transit Events
Historic Rittenhouse Town is hosting a Transit of Venus celebration and viewing party. Find out more.

About the Transit of Venus

In the annals of the American Philosophical Society, June 3, 1769 stands out as a defining moment. On that day, Venus passed between the Earth and the Sun in a rare astronomical spectacle called the Transit of Venus—an event that happens in pairs eight years apart, each pair occurring more than a century after the previous one. In 1769, it was an event that Members of the APS observed—one that put American science (and the APS) on the international map.

Although two other Transits of Venus had been observed, the first in 1639, the excitement in 1769 was worldwide because by then, scientists understood that if several accurate observations of Venus’s passage across the Sun were made from different points around the globe, the distance from the Earth to the Sun could be accurately determined for the first time.

A couple viewing the Transit in 1769.

APS Members saw the 1769 Transit as a splendid opportunity to display their abilities as natural philosophers by taking part in the international effort to provide accurate calculations. Beautifully clear skies greeted observers at three sites set up by APS members: John Ewing behind what is now APS’ Philosophical Hall; David Rittenhouse at his farm in Norriton (now suburban Montgomery County); and Owen Biddle at the lighthouse in Lewestown, Pennsylvania (now Lewes, Delaware).

Rittenhouse’s calculations proved remarkably accurate even though, because of a gap in his observations, he is believed to have fainted at some point during the Transit. His observations were published in the first issue of the Society’s Transactions in 1771, and also in the Royal Society’s Philosophical Transactions after Nevil Maskelyne, Astronomer Royal of England, attested to their accuracy.

This rarest of eclipses has happened only three times since then—in 1874 and 1882, and 2004. After this year, the next pair of Transits will occur in 2117 and 2125.

Image credits:
NASA, photomontage: www.astroevents.no / Knut Jørgen Røed Ødegaard. http://www.astroevents.no/venus060612en.html
Charles Willson Peale, Portrait of David Rittenhouse, 1791, American Philosophical Society
David Rittenhouse, Astronomical Transit Telescope, 1768-69, American Philosophical Society
Viewing the Transit of Venus, a French cartoon: http://sunearthday.nasa.gov/2012/transit/transitofvenus.php