SLAS Regular Meeting
Friday, July 20, 2012
7:30pm
McDonnell Hall
Washington University

When Worlds Align – A Solar Eclipse,
A Venus Transit

by

Members of SLAS

It is a rare event when three astronomical objects line up almost exactly – but that recently
happened twice within about two weeks. On Sunday, May 20 the moon passed directly between
the Earth and the Sun to cause a partial eclipse as seen from St. Louis. This was an
"annular eclipse" as seen from a narrow track that included parts of the American southwest.
Along a track just a few tens of miles wide, the Moon covered all but a narrow ring of the sun's
surface for a few minutes. From St. Louis, the Moon, at sunset, covered just over half of the
solar disc. Then, on Tuesday, June 5, the planet Venus crossed the solar disc, an event called a
transit. Venus transits occur in pairs separated by over a century. The next Venus transit will
not occur until 2117. Members of the Astronomical Society will show pictures and describe
experiences from the partial and annular solar eclipse and from the Venus transit. They observed
these events from Utah, Alaska and Hawaii, as well as from St. Louis.