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DO NOT LOOK DIRECTLY AT THE SUN WITHOUT EYE PROTECTION. IF YOU DO, YOU WILL DAMAGE YOUR EYES FOREVER! In this booklet we will discuss the transit of Venus, which is when the planet Venus drifts across the face of the Sun as we see it. At Sydney Observatory, we will use filters that block more than 99% of the harmful infra red and ultra violet radiation. Please ensure that everyone, especially children, only use the correct filters to look at the Sun. - 2 -
It is possible to safely watch the transit yourself if you have a small telescope or a pair of binoculars. Use the telescope or the binoculars to project the image, as shown in the image above. With your back to the Sun, aim the telescope towards it (this is not as difficult to do as it sounds use the shadow of the telescope) and focus its image onto a white card held about 200mm behind the eyepiece. Venus will appear as a black spot with a width of 1/33rd of the Sun s width and should be easily seen. DO NOT LOOK THROUGH THE TELESCOPE OR BINOCULARS! Never leave the telescope unattended and ensure that children are supervised at all times. Viewing the projected image is quite safe, but looking through the telescope or binoculars will cause almost instant and irreversible blindness. For a direct safe view of the Sun, a pair of Sydney Observatory eclipse glasses can be purchased for $5.00 each. - 3 -
Where will the 2012 transit of Venus be visible, and what about the weather? Image courtesy of Fred Espanak, NASA The transit of Venus occurs when the planet Venus drifts across the face of the Sun as we see it from Earth. You have to be in just the right position to see it and luckily here in Sydney, we will get a great view if the sky is clear. Yes, of course we are always worried about the weather! In the space below, keep a record of the weather for 6 June. The temperature at (time) today is C (you will find a large thermometer in the Russell Room) Image courtesy of the Bureau of Meteorology Circle the picture above which best describes the weather today. If it is cloudy, try to identify what type of cloud it is and draw a circle around it. - 4 -
Transit animation On the following pages, you will see several slightly different images of the transit. Hold the book in the centre at the top with your left hand and flip through the pages quickly from the front to the back. (The booklet needs to have been printed double-sided for this to work.) You will see a simple animation of Venus drifting across the Sun. We have put north at the top. - 5 -
We now know there are about 130 billion galaxies in the observable Universe. The Universe is about 13.7 billion years old. - 6 -
A single galaxy like the Milky Way may have 200,000 million stars in it. - 7 -
There may be as many as 20,000 stars just like the Sun in the Milky Way. SUN FACTS 5 billion years old 1.4 million km diameter 5,500 C surface temperature 10 million C core temperature Converts 4 million tonnes of hydrogen into energy every second To see the latest videos and images of the Sun from space visit http://www.nasa.gov/mission_pages/soho/ - 8 -
(not drawn to scale) The family of objects that travel around the star called the Sun (or Sol ) is known as the Solar System. Our Solar System has one star, eight planets, nearly 200 moons, eight dwarf planets and millions of comets and asteroids; but do they just wander all over the place? - 9 -
Lots of things rotate. This ice skater is rotating in an anticlockwise direction. Have you ever seen the hands of a clock move? If you watch very carefully you will see them move but quite slowly. Put an arrowhead on the end of the curved line to show which way the hands move. This direction is called clockwise. If you can go to Sydney Observatory, look for the models of the Solar System called orreries like the one shown above. Then look for the planet models. Two spin clockwise and one anticlockwise. 1. The planet spins anticlockwise. 2. The planet spins clockwise 3. The planet spins clockwise - 10 -
Faster than a speeding It is sometimes difficult to understand how fast our planets move. Passenger jets are even faster! They can travel at about 900km per hour which is about 250m per second. Some racing cars can travel at 300km per hour which is about 80m per second. That is nearly the length of a football field every second! Both racing cars and jets are slow compared to the planets. Mercury orbits the Sun every 88 days at about 48km per second. Venus orbits the Sun every 225 days at 35km per second. Can you name the planets on the dais in order? Our Earth orbits the Sun every 365 days at a slightly slower 30km per second. - 11 -
Many spacecraft have now been to Venus. The first landing on Venus was Venera 3 on 1 March 1966. It was from the former USSR but did not survive the incredible temperature of up to 463 C and atmospheric pressure 92 times greater than on Earth. Perhaps you can design your own spacecraft to survive the hostile environment of Venus. Sputnik 7 was the first mission to fly by Venus in 1961-12 -
As the planets orbit the Sun, sometimes they line up and eclipse, transit or block one another s view. What happened to the Sun in the picture below? Where has it gone? It looks like some of the Sun has been removed, but it is really just the Moon moving between us and the Sun, creating a shadow. Image courtesy of Fred Espanak Did you know some people thought eclipses were caused by dragons eating the Sun and Moon! Sometimes everyday objects or people line up too and can make an unusual sight, like this! - 13 -
Here we can see a simplified diagram of the Moon moving between the Earth and the Sun. This is called a solar eclipse. DO NOT LOOK DIRECTLY AT A SOLAR ECLIPSE! (not drawn to scale) - 14 -
The Moon orbits the Earth every 29 days but it rarely passes through the Earth s shadow. It does pass through the Earth s shadow twice every three years to cause a lunar eclipse. These are safe to look at directly. The next total lunar eclipses that can be seen from Australia are: 1. 15 April 2014 2. 8 October 2014 3. 4 April 2015 4. 31 January 2018 This series of images was taken in December 2011. - 15 -
Only three large objects can move between us and the Sun. Choose which three objects and draw a line from each one to its correct position. (not drawn to scale) - 16 -
(approximate scale as seen from Earth) The three objects that pass between the Earth and the Sun are: 1. The planet Mercury, 2. The planet Venus, and 3. The Moon. - 17 -
Venus is a very hot planet. The atmosphere is so heavy or dense it would crush us instantly. There is also a lot of volcanic activity. It is not a nice place compared to Earth. Draw a circle around the different features that you might find on Venus. Draw a cross through the features you wouldn t find on Venus VENUS FACTS Second planet from the Sun Hottest planet in the Solar System, with temperatures reaching up to 463ºC Atmospheric pressure 92 times that on Earth A day on Venus is 243 Earth days Only 650km smaller than Earth - 18 -
Mercury moves between us and the Sun about 13 or 14 times per century, Venus four times every 243 years and the Moon three times every two years. So why are we so interested in the rare transit of Venus? - 19 -
In 1768 a famous voyage took the HMB Endeavour from England to Tahiti to see the 1769 transit of Venus. Who was the captain? The Astronomer Royal, Edmond Halley, worked out how to measure the size of the Solar System. The idea was simple but proved difficult to do. Astronomers had to carefully observe the transit of Venus from different locations. They had to record the EXACT times of the four contact points. We ll talk more about them soon. At Sydney Observatory there is a model of the Endeavour. Internet question: What other famous ship had the same name? S S Endeavour - 20 -
Captain James Cook 1728-1779 Did you know the cottage where James Cook was born was moved to Melbourne s Fitzroy Gardens from England in 1934? We now know he took very good measurements of the four contact times: 1 st contact is when Venus first touches the edge of the Sun. 2 nd contact is when Venus is first fully inside the Sun. 3 rd contact is when Venus touches the edge before leaving the Sun. 4 th contact is the last touch of Venus on the edge of the Sun. Modern examination of Cook s data showed his error was just 1.5 seconds! Using his data, the distance from the Earth to the Sun was between 149 and 151 million km. The current value is 149,598,000 km. - 21 -
What did Tahiti and the planet Uranus have in common with King George III? Fort Venus At one time, both Tahiti and the planet Uranus were named after King George III, but not any more. Uranus, formerly Georgium Sidus Fort Venus, Tahiti, from Journal of a Voyage to the South Seas, Sydney Parkinson, 1784. Dixson Library, State Library of New South Wales. - 22 -
The next transit of Venus after Cook s voyage was in 1874. What famous observatory was built just 16 years before, in 1858? S n O _r _ y - 23 -
Henry Chamberlain Russell, Government Astronomer at Sydney Observatory from 1870 to 1904. At Sydney Observatory you can visit the 290mm telescope designed by H.C. Russell to watch the 1874 transit of Venus. It is one of the few telescopes in the world to have seen the 1874, 2004 and 2012 transits (provided it is clear). It can be found in the south dome. It is the o t working t _ s c e in Australia. (use all of these letters: esledletoc) - 24 -
Transit of Venus find-a-word How many of the following words can you find below? transit venus telescope captain cook planet moon clockwise tahiti observatory solar system galaxy universe mercury - 25 -
Join the dots to see where three different transits of Venus will have been seen (if it is clear on 6 June 2012). - 26 -
Important dates of the transit of Venus 1631 Predicted by Johannes Kepler 1639 Jeremiah Horrocks saw the first predicted transit 1769 Captain James Cook went to Tahiti 1874 Sydney Observatory s first transit 1882 It was cloudy everywhere and the transit couldn t be seen 2004 The first Internet broadcast of the transit 2012 saw the transit at 2117 The next one: it s only 105 years to wait. - 27 -
Some images from previous transits Henry Chamberlain Russell s book published in 1892 Make your own drawings here of the 2012 transit. Photograph by Geoffrey Wyatt of the 4 June 2004 transit of Venus Amateur astronomer Mr Alfred Fairfax s drawing from December 1874-28 -
Why is it important now? In the past we used the transit of Venus to work out the distance of the Earth from the Sun. Interestingly, the amount of light we see from the Sun drops as Venus transits. This can be measured very accurately. Astronomers now use this idea and watch other stars. If a star s light is observed to dim, they can tell if an exoplanet (a planet around a star other than the Sun) is present. It s not easy! - 29 -
Record your key contact times here ( Contact refers to the four times when Venus is just touching the Sun s outer or inner edge. They are very difficult to measure accurately.) First contact 8: am. This is when the planet Venus just appears to touch the Sun as we see it. Second contact 8: am. This is when the planet Venus first appears fully inside the Sun as we see it. Third contact 2: pm. This is when the planet Venus last appears fully inside the Sun as we see it. Fourth contact 2: pm. This is when the planet Venus just appears to leave the Sun as we see it. Make sure you visit www.sydneyobservatory.com/log-your-transit to enter your contact time data. This will be used to work out the distance from the Earth to the Sun. You will then receive a certificate of participation via email. - 30 -
Just to confuse everyone The flick animation to the right always has North at the top but that is NOT how we see it. The rotation of the round Earth actually makes the Sun look like it rotates too. If you were to mark the transit every half hour or so, it would follow a curved path! Fourth contact 2:44pm First contact 8:16am - 31 -
Autographs We saw the 2012 transit of Venus - 32 -
Credits Eclipse visibility courtesy of F. Espenak, NASA Common types of cloud image courtesy of the Bureau of Meteorology Produced by Sydney Observatory staff 2012 2012 Trustees of the Museum of Applied Arts and Sciences. See you for the next transit in 2 _, maybe - 33 -