14 May 2004

The transit of Venus

Readers who have been following Paul Curtin's "Eye on the Sky" column in The Citizen Scientist know that an extraordinarily rare and important astronomical event occurs on 8 June, when Venus passes between the Earth and the Sun.

No one alive today has ever seen a transit of Venus. That's because the events occur in pairs, each of which is more than a century apart. The last transit was in 1882. The one paired with the 8 June event will occur on 6 June 2012. The one following that will occur in 2117.

Unfortunately, the transit is not visible everywhere. In the United States, for example, the transit will not be visible in most of the Western States, including Arizona, California, Colorado, Idaho, Nevada, New Mexico, western Montana, Oregon, Texas, Utah, Washington and Wyoming.

For everyone else, there are many excellent web sites that describe the transit, its significance and how to view it. The ultimate site for eclipses and transits is the Goddard Space Flight Center's Eclipse Home Page under the expert care of webmaster Fred Espenak. The page on the transit of Venus is at
http://sunearth.gsfc.nasa.gov/eclipse/OH/transit04.html. This site was prepared by Espenak and Jay Anderson of Environment Canada. For Observer's Handbook 2004, Royal Astronomical Society of Canada. The web page includes history, significance, details on where the transit will be visible and many good links for more information.

The Europan Southern Observatory also has an outstanding transit page. It's at www.vt-2004.org/.Especially good is the teacher's guide at www.vt-2004.org/Education/vt-tg.pdf.

As with any observations of the Sun, it is crucial to follow safe viewing practices. The Sun must never be observed directly or through binoculars or telescopes without appropriate filters. These filters and other observing tips are described on the web sites above and on various astronomy web sites.

Forrest M. Mims III.