I hope you didn’t throw those eclipse viewing glasses away after last month’s Annular Solar Eclipse because in a couple of days you can use them again to view the planet Venus doing the same thing the moon did.
Just like solar annular eclipses, transits don’t happen all the time and of course, only two planets, Mercury and Venus, ever pass between the Sun and Earth.
The transit or passage of a planet across the face of the Sun is a relatively rare occurrence. As seen from Earth, only transits of Mercury and Venus are possible. On average, there are 13 transits of Mercury each century. In contrast, transits of Venus occur in pairs with more than a century separating each pair. [NASA]
Just like solar eclipses, aren’t visible from every point on Earth. Here is a map of the places where it will be visible on June 5th and 6th 2012
Observing the Transit of Venus
Venus is much further away from Earth so will appear far far smaller agaist the background of the sun than the moon did during the eclipse last week but we will still be able to see it without magnification using the same eclipse viewing glasses.
Nevertheless, the planet appears to be only 1/32 of the Sun’s apparent diameter so a pair of binoculars or a small telescope at modest power will offer a much more satisfying view. All binoculars and telescopes must be suitably equipped with adequate filtration to ensure safe solar viewing. [NASA]
NASA will be covering the transit of Venus live starting at 5:45 PM EDT.
Why can’t we see a Venus transit every year?
Good question. It’s because Earth’s orbit around the sun and Venus’ orbit around the sun are not parallel. Venus’ orbit is inclined 3.4 degrees from our perspective so most years it passes above or below the sun, but not directly across it.
-Mike
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