Tuesday, June 5, 2012

The Transit of Venus

Rick and Vicki Beno graciously invited the Portal-Rodeo community to their home to observe today's transit of Venus, with the aid of Rick's very fine telescopes. It was truly a marvel to see the phenomenon so well.

From our perspective on Earth, Venus was transiting across the face of the Sun. The view through the scope was heavily filtered to prevent any damage to people's eyes. (It's important not to look directly at the Sun!) Here is how it appeared this afternoon: who would have guessed it would be possible to digiscope the event?!

Transit of Venus across the Sun
(Photos by Narca, thanks to Rick and his equipment)

See the solar flares around the rim?

Pairs of Venus transits happen between long gaps of 121.5 and 105.5 years, with the entire cycle repeating every 243 years. The first transit of the current pair happened on 8 June 2004, and the first of the next pair of transits won't occur till December 2117, so not within any of our lifetimes.

The Venus transit was important historically because it gave early astronomers their best shot at calculating both the distance of Earth to the Sun, and also the dimensions of our solar system. The very first transit of Venus to be observed was in 1639 by Jeremiah Horrocks. Then Edmond Halley, of Halley's Comet fame, wrote of the scientific importance of observing a transit of Venus, but he didn't live long enough to do it himself. When the next pair of transits occurred in 1761 and 1769, scientists cooperated in making observations from many points on the globe. The first attempt in 1761 was partly successful, and set the stage for a much better effort in 1769, when even the famous Captain Cook participated.

Now astronomers are hoping to refine their methods of searching for extrasolar planets as they track and observe today's transit of Venus.

Watching the transit of Venus with Rick Beno, and with the backdrop of Cave Creek Canyon

It's no surprise that a little community of astronomers has found a home under the dark skies of the Chiricahua Mountains. Remember Comet Hale-Bopp in 1997? At its brightest here, the comet's tail covered as great an arc, roughly, as the Big Dipper. These starry skies are magnificent, and the astronomers who have settled here contribute a very fun dimension to the region's character.

Thank you, Rick and Vicki, for a fascinating opportunity!


  1. Excellent images of the transit. Sorry I was unable to make the viewing, sounds spectacular.