Transit of Venus

[likethebeer]

http://apod.nasa.gov/apod/ap120605.html

Tonight, the Iowa County Astronomy Society had a transit viewing event at a nearby park.* There were 4 telescopes, "eclipse glasses" so that you could look right at the sun, a special box that works like a pinhole box (and projected the transit across the face of the sun onto a piece of paper).

It started at 5:04 & was still going on when the sun set at 8:37. The clouds were thready, but cleared away by 6. It was really cool - there was one telescope with a filter that filtered everything out but red light waves (and the black from Venus). You could also see prominences coming out from the edge of the sun! Before the transit started, I was asked if I wanted to look at it and see the prominence. "Oh - WOW!"** I exclaimed (then I tried to stop myself from saying, "Holy shit!" which is usually my next exclamation in those cases).

I went to it because it is the last time we'll see this in our lifetimes. But I didn't realize how cool it would be. There was something awe inspiring about seeing this planet go across the face of the sun (even though it was just a black circle). And I feet like I never really understood how big the sun is until I saw the entire fricking planet being engulfed within its circumference.

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* The transit of Venus (I've learned) is cool in part b/c it's just neat; but also because it was a major, world, scientific community event in the 1700s - because they used the transit to estimate the distance of the Earth to the sun:
http://en.wikipedia.org/wiki/Transit_of_venus#Modern_observations

Aside from its rarity, the original scientific interest in observing a transit of Venus was that it could be used to determine the distance from the Earth to the Sun, and from this the size of the Solar System, by employing the parallax method and Kepler's third law. The technique involved making precise observations of the different durations of the transit when viewed from widely separated points on the Earth's surface. The distance between the points on the Earth was then used as a baseline to calculate the distance to Venus and the Sun via triangulation.

Although by the 17th century astronomers could calculate each planet's relative distance from the Sun in terms of the distance of the Earth from the Sun (an astronomical unit), an accurate absolute value of this distance had not been determined.

** The Iowa County Astronomers Society says that "you're in the club if you look up at the stars and say, "Wow!"

Comments

[low-delta.livejournal.com]

I didn't realize it would show up through a pinhole. I wish I'd tried that. But I was mowing the lawn.

[sirreal13.livejournal.com]

I tried, but didn't have enough time to perfect it. The sun sets early due to the trees and hills to teh west of us.

[likethebeer.livejournal.com]

The two pinhole boxes that were made by people who went did not work out well, I guess. Although there was this other box that had a little telescope that shown the image onto a mirror and bounced it back across the box - that one worked, and you could see sunspots!