How to witness the astronomy event of 2012: the transit of Venus

Last observed in 2004, the transit of the planet Venus will be one of, if not, the, astronomy event of 2012. You see, the next opportunity to witness it will be in 2117 as this alignment happens in pairs that are 8 years apart, but at intervals of over 100 years, and most of us I guess won’t be around to take that in!

Transit of Venus - Venus completely over the sun

Transit of Venus - Venus completely over the sun on 8th June 2004. Photo taken by Jan Herold (German Wikipedian)


What is a transit?

Good question. A transit occurs when a planet moves directly between an observer’s location and the star they are orbiting. In this case, Venus passes between us and the Sun, appearing to cross part of the disc of the Sun. As the side of Venus facing us will be in shade it will appear as a black disc.

Trying to find transits outwith our solar system is one way of trying to find potentially habitable exo-planets using telescopes such as NASA’s Kepler. Looking for dips in the light received from the stars it observes gives hints at planets that may orbit it.


So, when can I see the transit of Venus in 2012?

You’ll stand a chance of witnessing the transit of Venus on the 5th or 6th of June 2012 depending on your location on Earth, and of course, seeing it firsthand is highly dependant on local weather conditions. It will take around 6 hours 40 minutes for Venus to pass across the disc of the Sun on this occasion.

The map below shows that the transit will be visible across much of Europe on 6th June, though will already be underway as the Sun rises in the morning. For those in much of North America, the transit will have commenced on 5th June as the Sun is setting. Those at very high latitudes, the Far East and Australasia will see the entire transit.

The transit of Venus 2012 - visibility around the globe

The transit of Venus 2012 - visibility around the globe. Image: Fred Espenak (NASA GSFC)


Is it safe to view?

It is not safe to look directly at the Sun with the naked eye. Doing so risks permanently damaging your eyesight.

As Venus will be crossing in front of the Sun you should not attempt to look directly at the transit without appropriate safety equipment. Some of the safe ways to view the transit are:

  • Using a solar filtered telescope
  • Using a rear projection screen
  • Disposable solar (eclipse viewing) shades (NOT sunglasses!)
  • Watch a live webcast


Transit of Venus resources around the web

There’s lot’s of information about the transit around the web, including:


 *Updated 6th June 2012 – The last transit of Venus till 2117

About Derek Shirlaw

I'm passionate about science communication, social media, and my home country, Scotland. In particular, I have a real interest in astronomy, digital marketing, and the great outdoors.
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  1. Pingback: Derek Shirlaw » Get outdoors and look into the sky at night this April

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