Hot on the heels of the annular eclipse of a few weeks ago, we’ve another giant body passing in front of the sun tomorrow. Venus! This time the giant body (roughly the same size as the earth…just a bit smaller) is much further away from us, and so is dwarfed by the sun. It’ll be a tiny dot on the disc of the sun that takes several hours to pass across. This’ll give you plenty of time to look. (In the US, for example, it’ll start at about 6:06pm EST and about 3:06pm PST…) You won’t get another chance (at least, not from earth…) until 2117, so have a go!
In fact, you’ll be doing something that is vital for modern astronomy right now – observing the effects of a planet on the light of its parent star as seen from afar. This is the principal method for detecting planets moving around distant stars, the “extra-solar” planets you hear so much about in the news from time to time. Here, we’re seeing it happening for a familiar planet around a familiar star. Although both objects are quite familiar, this transit is still worthwhile to study, since it helps planet hunters learn more about how such processes can help deduce things about the planet doing the transit. So study it many will, I’m sure.
You can just look at it for fun, but remember to be careful. Do not look directly at the sun, and certainly don’t point any optical instruments at it while looking through them. Project onto a card using a pinhole, or using the instrument itself (telescope, binoculars, etc), and then look at the projected disc of the sun and look for the dot. There’s a NASA site with great information about it here. Or go to your local observatory. For those in Los Angeles, our friends at Griffith Observatory will be putting on an event for public viewing. See more here.
Should be fun! I hope to get out there and do it myself tomorrow. Will report if I’ve anything interesting to show.
-cvj
