Venus Transit begins at 3:06 p.m. PDT -- how to view it
Can I put 10 pairs of sunglasses together to view the sun?
No. You’re risking temporary or permanent damage to your eye. Only two kinds of commercially available vision filters are safe – solar filters sold at science museums and planetariums or a No. 14 welder’s glass. These filters block all but 0.003% of visible light, and also protect your eyes from harmful invisible infrared light.
So if I don’t have solar glasses, what can I do?
If you have a pair of binoculars, try focusing the light from the sun onto a sidewalk, and see if you can see a little dot on the sun after 3 p.m. through sunset. The planet will hit the center of its journey around 6:27 p.m. PDT. (The transit continues westward beyond the continental United States in Hawaii, and Australia, Asia and Europe, and ends just before 10 p.m. PDT.)
Some experts also suggest making a homemade pinhole projector. But others warn that while they may work during solar eclipses, it may be difficult to see the tiny dot of Venus using this method. Pinhole projection images are dim and small, according to the Exploratorium.
The best way, at this point, is to head to a Transit of Venus viewing party, because looking at the sight magnified through a safely-filtered telescope is the best option. You can find one at this NASA interactive map. For instance, Griffith Observatory and Columbia Memorial Space Center are hosting viewing parties with free access to telescopes equipped with special solar filters.
Or watch the event live online. NASA will anchor live Web coverage of the Transit of Venus from Hawaii. More webcasts of the transit are also broadcasting around the world, including one from Southern California's Mount Wilson.
Can I actually go blind looking at the sun?
Yes, you can lose your vision. B. Ralph Chou, an associate professor of the University of Waterloo’s School of Optometry, cited a study in the United Kingdom during a solar eclipse in 1999 when 70 people suffered burns to their retinas. Half of them wore no eye protection at all, and 35% said they wore sunglasses. (The remainder claimed they were using solar glasses, but they are presumed to be fibbing, Chou said).
It took some of these patients weeks for their vision to return. A person will not be immediately blinded by the sunlight; the process takes hours, and is painless, and they find that they cannot see the morning after the solar event. Vision loss can be as little as slight blurring to being unable to see your family across the breakfast table, Chou said.
The typical patient is an older teenage or young adult male, “one of those types whose genetics and development are such that they are unaware of or ignore all of the warnings that you give them. And generally don’t use any protection at all. Gee, that sounds like other things too.”
--Rong-Gong Lin II
Photo: A man prepares to press the shutter on his camera as he takes a picture of the sunset from Griffith Observatory. Credit: Robyn Beck / AFP Photo / Getty Images