There are some events that happen only once or twice in your lifetime, if at all. The last chance in this century to see the Transit of Venus across the Sun is on June 5-6. In most of the United States, it will only be visible in the hours before sunset on June 5.
The Transit of Venus occurs when it passes directly between Earth and the Sun. This occurs on a predictable pattern that repeats every 243 years, with a pair of transits occurring eight years apart, and gaps of 121.5 years and 105.5 years. The June 5-6, 2012 transit is the second of an eight-year pair, with the first having occurred in 2004. So if you miss this one, you will have to wait until 2117 to see the next one. There were no transits during the 20th Century.
I will mention this more than once, but it needs to be said. DON'T LOOK DIRECTLY AT THE SUN TO VIEW THE TRANSIT. If you do, you risk damaging your vision permanently. Did you ever use a magnifying glass to burn things using the Sun's rays when you were a kid? That is what the lens of your eye will do to your retina. Need I say more on that topic?
The transit will be visible at different times depending on where you are. Here is a NASA map showing where the Transit will be visible. http://eclipse.gsfc.nasa.gov/transit/venus/Map2012-2.GIF
To determine your precise local time for the Transit of Venus, you can use this website found
It will show you the exact times for the start of the transit, the peak and the end, as well as the path that Venus will follow as the transit progresses. The path of Venus between Earth and the Sun is not a straight line across the disk of the Sun because of the relative positions and motion of Earth, Venus and the Sun, and the rotation of Earth. It also varies greatly based on your location. If you enter your location, then try a couple of other locations, you can see how the shape of the path and the location of Venus relative to the Sun is different for varying locations. I checked my location near Pittsburgh, Pa., as well as Honolulu, Hawaii, and Anchorage, Alaska. It is interesting to see how greatly the path changes based on your location.
DON'T LOOK DIRECTLY AT THE SUN TO VIEW THE TRANSIT
There are several ways to view the Transit of Venus safely. You can purchase glasses with solar filters at any number of locations. If you do a search for "eclipse glasses" on any of the popular shopping websites you'll be able to find them for a reasonable price. I've seen them sold in five packs for around $8. They are nice to have on hand even if you don't get them for the transit, because you can use them to see other solar phenomena, including the upcoming annular solar eclipse (viewable only in parts of the southwestern U.S. on May 20), sunspots and solar flares.
Another option, that is cheap and can be used by several people at once, is to build a pinhole projector. There are a number of websites that show you how to build a pinhole projector using some cardboard boxes, a piece of aluminum foil and a piece of white paper. The one that I will be using can be found by clicking here.
One last time.... DON'T LOOK DIRECTLY AT THE SUN TO VIEW THE TRANSIT
I usually finish with Happy Stargazing, but in this case I'll say Happy Transit-gazing!
- Guest Blogger and Amateur Stargazer, Paul Adomshick
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