Safety Tips for Viewing the 2012 Venus Transit

The 2012 Venus Transit is a solar event as well as a planetary one, so if you want to watch it, experience it, and then talk about it for the next 105 years, you’re going to need to take a few precautions.

Most everyone knows that you should NEVER look directly at the sun; we just sometimes forget in the excitement of rare spectacles that safety procedures should be followed to protect the eyes. Even using proper solar filters, it is recommended that you not stare continuously at the sun; take breaks. Looking directly at it would damage your eye's retina, the light-sensitive area at the back of the eye that provides central vision, according to the American Academy of Opthamology.

And for goodness sake, DO NOT USE YOUR SUNGLASSES as a substitute for solar filter! Even those high-end driving sunglasses do not provide sufficient protection for viewing this event.

The following devices will not protect your eyes, the American Academy of Opthamology reports: sunglasses, binoculars with filters, neutral density filters, or exposed photographic or radiographic film.

Don’t let all these warnings scare you away from witnessing this rare, once-in-most-of-our-lifetimes event. Here’s some things you can do to make this a safe and memorable experience.

• Viewing with Protection -- Experts suggest that one widely available filter for safe solar viewing is No. 14 welder's glass. The welding hood MUST house a #14 or darker filter. (For example, a welder's helmet adversited online by Ace Hardware for $26.99 only has #10 welder's glass, which is unsafe.) It is advised that you do not view through any welding glass if you are not sure of its shade number. Arc welders’ glasses are generally NOT sufficient. Inexpensive Eclipse Shades have special safety filters that appear similar to sunglasses, but these filters permits safe viewing.
• Telescopes with Solar Filters – The transit of Venus is best viewed directly when magnified through a telescope with a solar filter; you’ll get to see Venus and sunspots. Never look at the sun through a telescope without a solar filter on the large end of the scope. The Atlanta Astronomy Club will have members throughout the area with specially equipped  telescopes and approved filters to share. Check out the on the transit for viewing parties in the region.
• Pinhole projectors – Most of us have made one of these for a middle school science fair and though not sophisticated, pinhole projectors provide a safe, indirect viewing technique that you can share with several people at the same time. While it’s a great family project, and provides some fascinating viewing, because it isn’t magnified, you won’t be able to see some of the more detailed features like the halo around Venus. Popular for viewing solar eclipses, pinhole projectors suffer from the same shortcomings as unmagnified views when Venus approaches the edges of the Sun. Here is a Stanford University project page to take you through the steps to make a pinhole projector, and one from skyandtelescope.com projectors.   
• Reflected Pinhole Projection: For a slightly different technique, you can try a "Reflected Pinhole Projector" as outlined in this project sheet from Trinity College Cambridge for the 2004 Transit.
• Scroll down in the story to find some links.

To see more about these safety techniques and for some very interesting and (dare we say it?) educational facts about the Transit and the planetary alignments, check out NASA's site here.