Weather angst and the Venus transit

Venus will transit across the face of the Sun Tuesday afternoon. This rare celestial event won’t happen again until the year 2117, and Northwest astronomy hobbyists, for good reason a highly pessimistic bunch when it comes to matters of cloud cover, have been warily watching the long-range forecasts since June 5 started to show up on the weather radar.

It is not looking pretty.

2004 Venus transit

The 2004 Venus transit was captured from Germany in this image by Jan Herold. Creative Commons, GNU free documentation license.

As of this writing, Saturday, June 2 at 4 p.m., the Seattle forecast for Tuesday afternoon was for clouds and a 30 percent chance of rain. The prediction for much of the Northwest looks similar. Our best bet as of the moment looks like Goldendale, with a forecast of merely partly cloudy and just a 10 percent chance of rain. (Really, we don’t care so much if it rains as long as it’s not cloudy!) Yesterday Moses Lake and Wenatchee looked promising, but those forecasts have flipped. We’d also been eyeballing the “rain shadow” of Sequim, but even that Olympic Peninsula town now has a wet forecast for Tuesday. The closest “sunny” forecast I am able to find is for Red Bluff, California. Do you roll the dice on an 11- or 12-hour drive, or hope for the best somewhere a little closer?

Many of us will likely be watching the weather forecasts up until Monday evening or Tuesday morning, making some last-minute decisions about where our chances look best for transit viewing, and then high-tailing it to those spots.

Of course, it’s possible, maybe even likely, that we’ll out-think ourselves on this decision. The lore of celestial event chasing is full of accounts of people who have made extreme travel efforts to get to places certain to be clear, only to find those locations socked in while the sky above their own backyards was crystal clear.

Why are we making such a big deal of this? Due to the peculiar geometry of the orbits of Earth and Venus around the Sun, we can only see a Venus transit occasionally. They come in pairs separated by eight years, and either 105.5 or 121.5 years go by before the next pair comes along. Tuesday’s transit is the second of a close pair. Unfortunately, the 2004 event wasn’t visible from the West Coast, and only the end of the transit was visible from the Eastern U.S. as the Sun rose that day. Europe, Asia, and Africa had the best views last time. So this is your last chance unless you make it to December of 2117.

There will be plenty of opportunities to enjoy the 2012 transit from Seattle if the weather cooperates. Events actually begin the evening before, Monday, June 4, at the University of Washington. Astronomy Professors Woody Sullivan and Victoria Meadows will give lectures about the significance and history of Venus transits. The talks begin at 7 p.m. in room 120 of Kane Hall on the UW’s Seattle campus. It’s free, but registration is required.

The UW will have several locations for viewing the transit when it begins at about 3 p.m. June 5. Viewing will also take place at the Pacific Science Center, Solstice Park in West Seattle hosted by Alice’s Astro Info, Battle Point Park on Bainbridge Island hosted by the Battle Point Astronomical Association, and others listed here by the Seattle Science Festival. Many of these sites will at least have online feeds, so participants can watch the transit as viewed from less weather-challenged areas. Other astronomy clubs are likely to be holding formal or informal transit viewings. Check their websites; links to them are at the right.

Seattle Astronomy will likely be at the Solstice Park event, unless we’re beating it to Goldendale.

Remember, don’t look at the Sun without proper protection. You’ll zap your eyeballs. Standard sunglasses are not good enough. This NASA website has some good pointers about transit viewing, eye protection, and pinhole projectors, as does transitofvenus.org.

Let’s hope we don’t miss our chance to see an astronomical rarity!

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