Chasing Venus
April 4, 2004 7:34 AM   Subscribe

Chasing Venus Transits of Venus occur every 130 years or so when Venus can be observed passing across the face of the sun. Chasing Venus is an online exhibition by Smithsonian Institution Libraries that tells the story of how the transit has been observed since the 17th century, with early observations in England, illustrated accounts of expeditions by 18th century astronomers to various parts of the world, and early uses of photography to record observations in the 19th century. Includes links to animations of transits reconstructed from Victorian photographs, and details of a lecture series on Thursdays in April and May (first one April 8). The first transit since 1882 is this year.
posted by carter (5 comments total)

This is fascinating. But I was curious as to how to pre-photography observations faired, considering how staring into the sun is usually a bit unpleasant.
posted by jb at 1:20 PM on April 4, 2004

But jb, that's where the fun is!
posted by Vidiot at 10:47 PM on April 4, 2004

You can use pinhole projection without anything like a camera. This is a fine way to view a solar eclipse, and I would think that with the proper conditions you ought to have a shot at viewing Venus in transit this way, but I offer no guarantees.
posted by Songdog at 9:05 AM on April 5, 2004

OK, I checked, and pinhole viewing is suggested by NASA for the coming transit, although they and others warn that a pinhole won't give you the best results. You'll get better success projecting the sun's image with binoculars onto a piece of white card or paper. A modern telescope is not a good idea; the larger objective lens focuses too much heat the eye lens, which could damage the optics. Be obsessively careful never to look through any magnifying optics at the sun or you'll almost certainly cause permanent damage to your eyes. Indeed, make sure you cover the binocular lens you're not using.

As it happens, Jeremiah Horrocks used projection with a telescope to make the first recorded observations of a transit of venus in 1639. I wouldn't use my telescope this way, though ...
posted by Songdog at 9:43 AM on April 5, 2004

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