An astronomical event that won’t occur again for more than a century took place Tuesday afternoon, and local sky watchers were on hand to help the community get a safe glimpse.
Beginning at 3 p.m., the planet Venus passed directly between the Earth and the sun. With proper viewing equipment, Venus appeared as a small black dot on the sun, according to Chuck McPartlin, outreach coordinator for the Santa Barbara Astronomical Unit.
“It’s rare, and it used to be of big scientific importance,” McPartlin said, noting that 18th century astronomers used what is known as the “Transit of Venus” to calculate the distance between the Earth and the sun, and the size of the solar system.
The transits happen in pairs about eight years apart, then don’t recur for more than a century. The next one will be in 2117.
Edmund Halley, best known for the comet named after him, came up with the idea to send expeditions around the globe to measure future transits of Venus, as a means of determining absolute distances of the various planets and the sun. He did not live to see the 1761 transit, but his theory guided future astronomers.
As with eclipses, it’s important not to look directly at the sun when viewing the Transit of Venus. Doing so, even for brief periods, can cause severe eye damage and blindness.
As they did for the recent solar eclipse, McPartlin and his colleagues in the Astronomical Unit set up special telescopes and viewing devices at the Camino Real Marketplace in Goleta to allow the public to share the astronomical experience.
Their telescopes were outfitted with special filters that allowed only .001 percent of the sun’s light through, McPartlin said.
McPartlin cautioned against trying to view any eclipse through homemade set-ups such as mylar balloons or CDs. Most don’t provide adequate protection to the eyes, he said.