Geek Tuesday: Transit of Venus

This colorized image of Venus was recorded by the Jupiter-bound Galileo spacecraft shortly after its gravity assist flyby of Venus in February of 1990. Galileo's glimpse of the veiled planet shows structure in swirling sulfuric acid clouds. (Galileo Project, JPL, NASA)

Tuesday is the Transit of Venus. Starting at 5:45PM Eastern time, people can view Venus traveling across the face of the sun. Depending on where you are in the world, you may have the last opportunity to witness this event in your lifetime, given perfect viewing conditions. (If you don’t have perfect viewing conditions, there are loads of webcasts.) The next one will not occur until 2117.  When this spectacle occurs, they occur in pairs, 8 years apart. However, the next one will not occur until 2117. I’m pretty sure everyone who can see this one will not be around for the next. So grab your sun-staring goggles and let’s watch!

WARNING: For skywatchers who are planning to view the transit of Venus in person, it is important to exercise caution. It is very dangerous to stare directly at the sun. Special eclipse glasses and filters for telescopes are needed to avoid permanently damaging your eyes.

For NASA’s complete list of Venus transit webcasts, visit:

What is a Transit?
“Transit” is just the word astronomers use to describe one cosmic body passing in front of another from a third object’s perspective. For example, a lunar eclipse. “The transit of Venus, therefore, simply describes the event wherein Venus passes in front of the Sun as viewed from Earth. But Venus and Earth do not orbit the Sun in the same amount of time (the Earth takes 365 days, Venus 225); nor do they orbit the Sun in the same plane. As a result, it’s rare for the three bodies to align in such a way that Venus’ path across the Sun is visible from Earth.” (reference: io9 article) Hence the reason the next Venus Transit will not occur until 2117.


Check with your local planetarium or astronomy clubs. I’ve seen plenty that are setting up viewing events in many cities.

Or you can use an old method I was taught a long time ago to watch a solar eclipse called the Pinhole projection technique:

Poke a small hole in an index card with a pencil point, face it toward the Sun, and hold a second card three or four feet behind it in its shadow. The hole will project a small image of the Sun’s disk onto the lower card… Experiment with different size holes. A large hole makes the image bright but fuzzy; a small hole makes it dim but sharp.

There are also a number of streaming web casts you can attend and listen to commentary while it happens. These are great for those of you suffering from too many clouds. Or even those of you who want to hear more in-depth geek facts and conversations about this awesome event! like me! :D  Check out NASA and SLOOH.

Transit of Venus


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