The transits of Venus, they are like an eclipses, are very rare but when they occur there are two such events 8 years apart. During the transit Venus is positioned between us and the sun and casts a shadow. Unlike an eclipse of the moon this show is small and seen as a small dark dot as it moves across the face of the sun.
This is only the fifth transit since James Cook travelled to Tahitti in 1769 to make observation there. Astronomers back in England wanted to know exactly how long the transit took and from that they predicted they would be able to compute the distance of the earth and Venus from the sun. This trip is also famous because on the way back to England he reach Australia, called it New South Wales and claimed it for England.
When?There are four key events in the transit
|First touches the sun|
|Just inside the Sun, ingress|
|Just inside the Sun, egress|
|Last Touches the Sun|
Where is the best place to observe?Well really anywhere around Venus Bay you can see the sun at the times above. Remember the sun will be relatively low in the sky during the Ingress. So I might start my own observations just near lees Road and Jupiter avenue intersection, on the bike track as it comes off the little rise. There is a very clear view of the eastern sky from here. During the Egress the car park at Beach One is a good location as it has a good view of the north western sky.
The Venus Bay, Tarwin Lower Men’s Shed are having activities around observing the transit, weather permitting, including a sausage sizzle & live music from local artists. They will have a solar telescope for safe viewing of the transit, solar flares, sunspots and active regions of the sun. Gold Coin Donation. Check the May edition of Matter of Fact Newsletter for more details.
How to Observe?I will be using the same method used by captain cook. I will project an image of the sun onto a screen using my telescope. I took the picture below of the transit in 2004 and I’m hoping I can do better this time.
The Sydney observatory has a great factsheet on the 6 June 2012 Transit of Venus. If you’d like more information of making observations yourself, it will even help you do the calculations of distance to the sun and Venus if you want to independently verify the astronomers work.