Scientists eye new data expected from
by Peter Duveen
Archivist Randall Rosenfeld helps elucidate obscure details
about the upcoming transit of Venus at a recent conference in Toronto,
PETER'S NEW YORK, Sunday, June 3, 2012--The University of Toronto will
highlight a relatively rare astronomical event on Tuesday with a
multimedia presentation at its Varsity Stadium. Not only will the
Transit of Venus be projected onto a large viewing screen, but special
disposable eye gear fitted with specially treated plastic filters will
be distributed to the crowd to prevent anyone from having their vision
impaired due to the damage that often results from directly viewing the
sun. The planet Venus will show up as a round black dot during a
six-hour pilgrimage across the sun. During the transit, there will also
be a performance in the stadium of part of an opera, the plot of which
is based on the true story of a man who sacrificed practically
everything of value in his life to view the event.
Transits have been observed at least since 1639, when knowledge of
astronomy reached a stage advanced enough to predict precisely when the
planet Venus would post itself between the earth and the sun, thus
enabling earthlings to see the silhouette of the planet against the
disk of our nearest star. This happens two times within the space of
about eight years, after which more than a century passes before the
next transit. After Tuesday, more than a hundred years will pass before
the cycle recurs.
At one time, hopes were high that accurate measurements of the
event from different vantage points on earth could be used to gage the
distance of the earth from the sun. In fact, measures obtained from the
observation of the 1639 transit by Jeremiah Horrocks, an English
astronomer in his early 20s, did yield an improved calculation of this
distance. But transits have not been employed for this purpose since
the late 19th Century, when astronomers developed more accurate means
for measuring the diameter of the earth's orbit.
Yet those who have been emphasizing the transit have found fresh
reasons for scrutinizing it. During the last event in 2004, it seems
that, just before the planet began its journey in front of the sun, its
atmosphere lit up in the form of a bright halo surrounding its surface.
This appears to have been the first time the Venusian atmosphere was
observed from earth-based telescopes.
Close to a hundred participants are engaged by, from left to
right, Paul Greenham, Erich Weidenhammer and Ari Gross and Erich
Weidenhammer, who have worked to established a budding museum
consisting of scientific equipment gleaned from various departments at
the University of Toronto.
At a recent conference (April 28) hosted by the University of Toronto's
Institute for the History and Philosophy of Science and Technology, Dr.
Jay M. Pasachoff, director of the observatory at Williams College in
Williamstown, Mass., explained to a gathering of about 100 participants
that more accurate observations of what he called "atmosphere
scattering" would be made during the Tuesday event.
An additional reason for paying close attention to the transit,
according to another presenter, Dr. James Graham of the Dunlap
Institute of Astronomy and Physics, will be to take measurements of
exactly how much the sun dims when Venus obscures ever so slightly the
output of light and heat put out by our closest star. These
observations, Dr. Graham explained, can be used to interpret similar
dimmings of far-away stars, thus enabling astronomers to formulate
ideas about the size of planets that may be orbiting them.
Professor Jay M. Pasachoff of the Hopkins Observatory at
Williams College in Williamstown, Mass., remarks on observations of the
The day-long conference featured a diverse roster of speakers, each
addressing a particular facet of the transit. Department head and
renowned historian of physics and mathematics Dr. Craig Fraser offered
a general introduction, followed by Randall Rosenfeld, archivist for
the Royal Astronomical Society of Canada, who treated the conference to
a rendition of a complicated baroque musical piece on a rustic
hand-made flute. Rosenfeld was followed by Dr. Bernard Lightman of York
University, who led the audience through the complicated debate between
two 19th Century astronomers who failed to see eye-to-eye on exactly
how observations of the transit should be made.
Midway through the day, Paul Greenham, Ari Gross and Erich Weidenhammer
of the Institute took participants on a tour of what is shaping up to
become a museum for astronomical instruments whose historical value has
superseded their practical utility. Among these was a telescope used
for viewing the transit of 1882, about which so much hullabaloo
occurred regarding the expensive expeditions sent around the world to
observe it. Included in the featured instruments of the museum was an
electron microscope, ads for which the writer remembers seeing in
Scientific American magazine when he was a preteen.
A telescope used to view the 1882 transit of Venus is one of the
exhibits in a fledgling museum on the premises of the University
Composer Victor Davies played prerecorded excerpts of his opera,
Transit of Venus, while projecting scenes from the opera on a viewing
screen. The work's elaborate plot line, based on a play by Maureen
Hunter, would have made Puccini's librettists blush. Dr. Michael
Reid and Mubdi Rahman of the Dunlap Institute discussed ways in
the transit could be used as a teaching opportunity for high school
students. Dr. Ralph Chou of the University of Waterloo suggested ideas
for viewing the transit safely, and documented the type of eye damage
experienced by careless observers in past years. Others assisting in
the production of the conference included Rebecca Michaels, John Percy
and Teresa Branch Smith.
Composer Victor Davies reviews the story line of the opera he
completed on the theme of the transit.
All presenters emphasized that observations of the transit should be
conducted cautiously, with attention paid to observing it without
injuring the eyes. The image of the sun can be projected from a
telescope, or even through a pinhole in cardboard, onto a screen where
it may be viewed without danger. Various types of treated glass and
plastic are used for the purpose of viewing the image of the sun
directly without damaging the eyes. Even better, one may travel to the
University of Toronto, where the event can be viewed live at Varsity
Stadium on screens that will provide perhaps the best images possible
for the enjoyment of the educated layman.
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