Warning: Never directly view any sun-related phenomenon without using adequate eye protection. See more on this below. The BirminghamPoint.co blog officially advises against any attempts at viewing this event directly, and recommends restricting one’s ‘observations’ to online or news resources, only.
The annular solar eclipse of May 20th was a bit of a bust for those of us outside its viewing area. However, Mother Nature will be providing us with an even more significant celestial event on Tuesday, June 5th, 2012: A rare transit of the planet Venus across the face of the sun. For those of us in the eastern United States, the transit begins just before sundown, at approximately 6PM EDT.
Venutian transits are extremely rare. They occur in “pairs”, separated eight years apart, with 121 years passing before the next pair occurs. And pairs alternate between June and December. The first transit of the current pair happened eight years ago, in June, 2004, with the second (and last) transit occurring this coming Tuesday. The next transit will not happen until December of 2117.
Normally, Venus spends about 9 months of a given year as an evening star (Hesperus; appearing after sunset), then transitions to a morning star (Phosphorus; appearing before sunrise) for another nine months. During its transition from one phase to the other, Venus either crosses in front of the sun (inferior conjunction), or passes behind the sun (superior conjunction).
The transit is simply an inferior conjunction where Venus is not just in front of the sun, but on a trajectory between the sun and earth. It’s essentially an eclipse; only, unlike a solar eclipse by the moon, the apparent size of Venus is far too small to block large portions of the sun from view. Since Venutian transits are so rare, we all should consider ourselves fortunate to be living in a century experiencing a transit-pair.
If you plan to view this event (and you proceed at your own risk, if you do), adequate eye protection is essential. A #14 welder’s glass, or an equivalent sun filter on your telescope or binoculars (and in either case, acquired from a trustworthy source) is required. And even though you’re using adequate eye protection, also limit your viewing time to just a few seconds. If you don’t have adequate eye protection, avoid it altogether, and be satisfied with the multitude of photos that you know are going to be published on the Internet, anyway. A telescope isn’t necessary to see the Venutian transit, but keep in mind that you’ll be looking for a tiny dark spot in front of a sphere that’s about the same apparent size as the full moon.
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MSNBC Video: NASA TV’s coverage of the Venus Transit.
Venus Trans from Keck Observatory, Hawaii.
More Information on Safe Viewing and Other Resources
For an excellent account of the Venutian transit, and an explanation of how transits are leveraged in the discovery of new exoplanets, I highly recommend the following article by John Rennie of Smart Planet.
On Twitter, #venustransit seems to be the hash tag of choice. Track this one. You’ll probably find both amateur and professional astronomers and other sources posting tweets with images or links to this hash tag, during and after, the actual transit.
So happy viewing to all….And remember: No adequate eye protection, no viewing!