The Next Transits of Venus, 2 Months and 105 Years

The next transit of Venus will occur two months from yesterday.  They are rare – after that we will have to wait until 2117 to see another one. We did have a similar transit in 2004, but that was not visible from the West Coast. This time we will be able to see the first 80 percent of the event, including the critical 17 minutes of ingress. The talk will briefly describe the celestial geometry that causes such transits and why they are so infrequent, along with their significance in the history of astronomy. The particular circumstances of the 2012 transit, including its visibility from the Bay Area, will be covered, along with recommendations for safely watching the event, including two phenomena of special interest – the infamous "Black Drop" and the subtle aureole caused by the planet's atmosphere.