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.
And for goodness sake, DO NOT USE YOUR SUNGLASSES as a substitute for a solar filter! Even those high-end driving sunglasses do not provide sufficient protection for viewing this event.
But don’t let these warnings scare you away from witnessing this rare, once-in-most-of-our-lifetimes event. If you don't have protective gear, the easiest way to go is a viewing party. The Reuben H. Fleet Science Center in Balboa Park will host a safe viewing of the transit of Venus across the sun starting at 3 p.m. Tuesday.
If you're viewing at home, here are 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. 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.
- 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.
And though we’ve not discovered any local channels that are advertising the live viewing of the Venus Transit, you can certainly watch it online:
- The Slooh Space Camera will offer an eight-hour webcast of the transit that includes real-time video feeds from 10 telescopes around the world.
- Astronomers Without Borders will carry a video stream of the transit from the Mount Wilson Observatory in California.
- NASA will offer a live video feed from Mauna Kea observatory in Hawaii with expert commentary.
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.