Date: January 28-February 3  

Astronomers without Borders are supporting a world wide effort to re-created the measurements of the parallax of Eros. First carried out in 1931, measurements of the exact position of the asteroid can be used to precisely determine its distance. This then gives the distance to the Sun!

Parallax can be seen by holding a finger out at arm’s length. Close one eye and see what your finger is in front of. Then, open that eye and close the other and see how your finger has appeared to move. No matter how still you try to keep your finger, it will move against the background as you change your viewpoint of it.

Now for Eros – it will be the finger, different observers on the Earth will be the eyeballs and the distant stars behind Eros will be the background. With a little geometry, the distance to the asteroid can be calculated.

To take part check out the Transit of Venus website and be prepared to take photographs of Eros between January 28 to February 3, 2012.