June 5, 2012

June 5, 2012

Going to the Mt Lemmon observatory two weeks ago reawakened my interest in astronomy. Today I pulled out my old telescope today to watch one of the rarest of celestial events, the transit of the planet Venus across the face of the Sun. It is so very uncommon because the orbit of Venus is tilted compared to our own. The next one won't occur until 2117. To safely observe it, I had to attach my solar filter onto the eyepiece.

I watched Venus slowly crawl across the edge of the sun. I am in good historical company. In 1769 Captain James Cook sailed to the other side of the world to observe the transit of Venus in Tahiti. He was one of many sent all over. By comparing distant results, scientists through triangulation were able to calculate the distance of the Earth to the Sun. 93 million miles or one Astronomical Unit (AU).