Tonight beginning at 22:09 UTC, Venus will appear as a dark spot in front of the sun for the first time in eight years, and for the last time for more than a century — the next transit of Venus won’t occur until December, 2117.
One of the best sites to help visualize this even is using the viewer on HeyWhatsThat.com. It allows you to adjust the time and your location and get a view of exactly what the sky will be looking like. It’s quite impressive and very helpful.
As with the solar eclipse a few weeks ago, Xavier Jubier has put together some great maps to show what will be going on.
In addition to the standard map showing where the transit will be visible, Xavier also shows us a map (via Jay Anderson) that includes mean cloud cover for June, which helps to show your likelihood of actually having a clear sky with which to view the event.
As with a solar eclipse, do not look directly into the sun (even with sunglasses on) to try to view this event. There are ways to do it safely and we strongly encourage you to take those precautions.