Francine, that's a great little video.

When I wrote my article Transit of Venus - Measuring the Solar System this was the bit I found hardest. An animation shows that it isn't so complicated, but explaining in words - even with a diagram - leaves a lot of conceptualization to the reader. As a person who doesn't have a great sense of spatial awareness, I understand how difficult this conceptualization can be.

Transits are rare for much the same reason solar eclipses are rare. If the Moon's orbit weren't tilted with respect to Earth's orbit, we'd see one every new moon. (I'd love that!)

But back to the BBC video, I'm quite envious of their great special effects that seem to put the planets in your hands. More effective than having the presenter voice over an animation. The only thing I would have liked to add would be near the end to show the orbital paths of Earth and Venus so you could clearly see that the transits occurred where they intersected.

There was a dramatic conjunction of Venus and Jupiter in the evening sky the first part of this year. Those planets got closer than I have ever seen them and made a pretty sight with the crescent moon. So, I learned that when Venus leaves the evening sky to pass into the morning sky, it passes in front of the sun. It follows that as Venus goes from being the �morning star� to being the �evening star,� it passes behind the sun. Venus spends 9 months in the evening sky and 9 months in the morning sky. There will not be another transit of Venus until 2117. Everyone living now will be gone. It is hard to say what the world will be like in 2117. I am sure these cargo pants, SUVs and sunglasses atop shaved heads will have passed, which is a good thing. But every century brings with it its own brand of evil. That is, if you want to call undesirable things �evil.� Biblical terms tend to confuse.

Transit of Venus http://en.wikipedia.org/wiki/Transit_of_Venus,_2012

Francine, I'm glad you found the article to be clear. I have the double advantage of being a teacher and of having worked hard to understand some of these things myself. (Still working at some of them!)

I have an eastern horizon, but the weather is being very uncooperative, so will probably not see the transit as the Sun rises on Wednesday.

But it is being webcast all over the place, so I'll paste in here what I put on one of my other transit threads:

There are lots of places that are going to webcast the transit and as the whole thing lasts for about seven hours, you'll have many chances to tune in. After a look round, I thought this was the best place to steer you.

NASA Transit of Venus webcast

NASA will be following the whole transit from Mauna Kea in Hawaii, but on the page there are links to several other live webcasts, so you have a good choice. There's even a link to the Space Station � they can't do a continuous live feed, but will be posting pictures and perhaps video.

I'll also note that the Exploratorium � one of my favorite places � will have a live feed from Mauna Loa in Hawaii.

Exploratorium feed for transit of Venus

Remember! DON'T look directly at the Sun unless you have correct eye protection. DON'T look at the Sun through telescope or binoculars unless they have correct filters on the objective lenses-eyepiece filters aren't safe.

I watched the beginning of the transit online and got up early this morning to see the end, but didn't see anything except clouds where the Sun was.

Since blue is my favourite colour, I liked the view using the calcium line filter. You can see Venus and some sunspots. This is from the Exploratorium live feed on Mauna Loa, Hawaii.

The transit came and went. Like everything else. I'm looking forward to 2117.