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A Transit of Venus is when planet Venus passes in front of the Sun as seen from the Earth. This happens at intervals of 121.5, 8, 105.5, 8, 121.5, 8, etc. years. Transits of Venus were observed in 1639, 1761 and 1769, 1874 and 1882 and in 2004. After 2012, one will have to wait until 2117 to see another one.
It was realised in the past that a Transit of Venus event observed from different places on Earth could lead to a direct measurement of the size of the Solar System. The events in the 18th and 19th century led to worldwide expeditions to do exactly that.
In 2004, the exercise was repeated by amateur astronomers and students. Scientists used the Transit to learn more about the atmosphere of planet Venus and about how to observe exoplanets transiting their mother stars. In 2012, similar actions will be organised all over the world.
In the film, we will follow three groups of people: scientists who study Venus and exoplanets, amateur astronomers and historians who will observe this Transit with instruments from the 18th and 19th century!
Post by Paulie pchris00 on Oct 19, 2011 8:49:29 GMT -6
I won't be using instruments from the 18th &19th centuries, but I plan to get data according to the method of DeLisle. He proposed that only one set of contacts would be necessary from a given location, and compared to data from a site of different latitude could be used to determine parallax, and thus the scale of the solar system. As long as I can collect good data, I'm not overly concerned about actually determining parallax, but I do have somebody in mind to partner with in Australia, if she is interested.
I'm going to be limited to equipment I already have, with maybe slight upgrades to cameras. I need to invest in Baader film soon, and start getting observing tests in. My last observation of a lunar occultation of a star revealed that I need practice beforehand to ensure I don't have unexpected problems. This is my last shot at a Venus transit, and it will be no time for mistakes.
"Just a boy, just an ordinary boy, but he was looking to the sky." -Vanessa Carlton
I've created graphics that preview the transit from different cities, including Chicago at the Adler Planetarium (well serving all Chicagoland observers). The timings vary among locations since parallax is a factor. My diagrams utilize horizontal (alt-az) coordinates which explains the apparent curving of Venus' path due the Earth's rotation. I currently provide previews for eighteen cities, but will add more as the event nears. Here's the link to my webpage for the transit: www.CurtRenz.com/venustransit