transit of venus - history
"I then beheld a most agreeable spectacle, the object of my sanguine wishes..." Jeremiah Horrocks
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Press Pack - FAQ

Introduction

On Tuesday 8th June 2004, astronomers and historians from across the world will open a window on a past triumph of science when they witness a spectacular astronomical event that no living person has witnessed: a Transit of Venus.

On this day, half of our planet will be able to watch the very rare event of the black disc of the planet Venus moving across the bright orb of the Sun ? this is known as a 'transit'. The last time this phenomenon took place was in 1882 but after 8th June 2004 it will not reoccur from the UK until 2247.

The Centre for Astrophysics within the University of Central Lancashire (UCLan) has been selected as the UK?s focal point for all activities connected with this spectacular astronomical event

Questions

1. What will happen during the transit?
2. How long will it last?
3. Why are Venus transits so rare?
4. Why is a transit of Venus so important?
5. How can I observe the transit of Venus safely?
6. What can I learn from observing this Transit of Venus?
7. Events around the UK
8. List of relevant images with captions
9. Relevant WWW sites
10. Points of Contact
Disclaimer

1. What will happen during the transit?

On Tuesday 8 June 2004, anyone throughout Europe, as well as most of Asia and Africa, will be able to witness a very rare astronomical phenomenon when the planet Venus lines up directly between Earth and the Sun.
Venus is the second planet from the Sun; we live on the third planet, Earth. On 8th June 2004, Venus comes directly between the Sun and our planet and it will be seen to move across the bright solar disc. Viewed from Earth, Venus will appear as a black dot moving slowly from left to right across the southernmost part of the Sun?s bright disc. With a diameter of approximately 12,103 km, 114 Venus sized circles could fit across the full width of the Sun. On the day, Venus will be 43 million km from Earth.
For a diagram of Venus's track across the Sun, see
transit-of-venus.org.uk/transit.htm

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2. How long will it last?
Well that depends where you are in the world! Not everyone on Earth will be able to view the transit. NASA has produced a world map indicating what countries will be in the path of the transit. Also, NASA has provided information on the start and end times of the event for many major cities across the world.
As an example, take the location where Jeremiah Horrocks first predicted and observed a transit of Venus on 1639 ? that is Much Hoole, near Preston, Lancashire, United Kingdom. The transit will start at 06:19am and end at 12:23pm having lasted for just over 6 hours.

NASA links:
? world map: sunearth.gsfc.nasa.gov/eclipse/transit/venus/Map2004-2.GIF
? start and end times: sunearth.gsfc.nasa.gov/eclipse/transit/venus/city04-1.html
? major cities: sunearth.gsfc.nasa.gov/eclipse/transit/venus/city04-1.html

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3. Why are Venus transits so rare?
You do not have to wait too long as the next transit of Venus is in 8 years time (6th June 2012). However that will not be visible from the UK and after that there will not be another one in your lifetime.
Occurrences of Transits of Venus follow an unusual pattern. The last one was in 1882, a gap of 121 years until the event in 2004. Then in 2012, Venus will be in transit again (8 years later). However, we are going to have to wait another 105 years until the next transit of Venus in 2117, then 2125 and then 2247! The next one visible from the UK will be in 2247 ? a long time to wait and even more reason to try and observe this one when you can!

Venus laps the Earth every 1.6 years. But we do not see a transit occurring on every occasion because the journey of Venus around the Sun (its orbit) is slightly at an angle (or inclined) to the path that the Earth makes around the Sun.

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4. Why is a transit of Venus so important?

There are a number of reasons why a transit of Venus is important including:-

? The rarity of the event ? there have been only 6 transits of Venus since the invention of the telescope in 1608. After the 2004 Venus transit, the next one that can be observed in the UK is not for 243 years!

? The importance of this event in history ? Kepler, Horrocks, Crabtree, Halley and Captain James Cook are just some of the famous historical characters whose lives are connected intimately with transits of Venus. For information on the influence of transit observations through history, see

sunearth.gsfc.nasa.gov/sunearthday/2004/vt_edu2004_venus_back_his.htm
transit-of-venus.org.uk/history.htm

? Measuring the scale of the universe - In the 18th and 19th centuries, transits of Venus presented rare opportunities to tackle a fundamental problem - finding an accurate value for the distance between Earth and the Sun. The unit astronomers use for distance measurements in the solar system is based closely on its average value and is called the astronomical unit (AU). It is approximately 93 million miles, or 150 million km.

? Opportunity for mass participation in astronomy ? through simple but safe telescope or pinhole camera observations and with the World wide Web allows images to be broadcast from all over the planet, the 2004 transit of Venus is a truly global event. More people than ever will be able to participate directly in observing this rare phenomenon.

? Observing planet transits around other stars - astronomers are using the principle of a transit as a way of hunting for planets outside our solar system. When a planet crosses in front of its parent star, there is a minute dip in the star's brightness and some astronomers intend to use the transit of Venus as a test to help design searches for extrasolar planets. For more information see : on the influence of transit observations through history, see

http://planetquest.jpl.nasa.gov
www.exoplanets.org
www.pparc.ac.uk/nw/newplanets3.asp

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5. How can I observe the transit of Venus safely?

Never look at the Sun with the naked eye or through a telescope, binoculars, camera or any other optical device. Viewing directly through a telescope or similar will result in blindness.

The only safe means of observing are:
? By PROJECTION of an image of the Sun onto card through a pinhole camera or telescope
? Through devices with dedicated SOLAR FILTERS including eclipse shades and solar-filtered telescopes.

If you are unsure about a solar-filtered device, do not use it.

For further information as to how to observe the Sun safely see
transit-of-venus.org.uk/safety.htm

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6. What can I learn from observing this Transit of Venus?

As indicated above, one of the main reasons for careful measurement of the path of Venus across the Sun?s bright disk is that it allows you to use some basic mathematical concepts to calculate the distance from the Earth to the Sun.
Thus the UCLan web site also enables interested individuals (school pupils, amateur astronomers etc) to do some simple observations during this transit and then calculate the value of the Astronomical Unit (AU: the Sun-Earth distance) for themselves. With the help of UCLan?s specially developed interactive ?transit calculator? anyone can make their own estimate of the AU and see how close they are to the accepted value of 149.598 million km.

Details on how to take the observations and use the UClan Transit Calculator can be found at

transit-of-venus.org.uk/otday.htm

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7. Events around the UK
On the UCLan website, an events calendar can be found. This exhaustive list provides individuals throughout the UK with the opportunity of searching for transit of Venus activities in their local area as well as allowing amateur astronomers, museums, science centres, school groups etc to publicise their own transit event.

transit-of-venus.org.uk/events/

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8. List of relevant images with captions

A selection of high resolution images of Venus, the Sun, the Venus transit path as well as some artist impressions of the event can be found at

transit-of-venus.org.uk/pictures.htm

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9. Relevant WWW sites

University of Central Lancashire website that is the UK hub for ToV activities
transit-of-venus.org.uk

European Southern Observatory website coordinating ToV activities across Europe
www.vt-2004.org

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10. Points of Contact

University of Central Lancashire Media and Public Relations Office
Chris Theobald
Phone: /5
E-mail:

Gemma Thomas
Weber Shandwick
Phone:
E-mail:

Astronomers
Dr Robert Walsh
Phone:
E-mail:
Special expertise: Transit of Venus; the Sun as a Star; SOHO, TRACE

Dr Stewart Eyres
Phone:
E-mail:
Special expertise: Transit of Venus; Stellar physics

Professor Gordon Bromage
Phone: /9
E-mail:
Special expertise: Transit of Venus; Stellar physics; IAU conference organiser

Professor Don Kurtz
Phone:
E-mail:
Special expertise: Transit of Venus; Stellar physics; astroseismology; IAU conference organiser

History
Dr Paul Marston
Phone:
E-mail:
Special expertise: Jeremiah Horrocks; History of Science/Astronomy/Religion

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Disclaimer
The University of Central Lancashire has taken all reasonable care to ensure that the information on this web page was accurate on 5th January 2004 but does not warrant that it is accurate or complete, and disclaims liability (except in where death or personal injury arises from the negligence of the University) to the fullest extent allowed by law for all and any damage, injury and/or loss (whether direct or indirect, consequential or economic) caused or suffered as a result of use of or reliance on that information. This disclaimer is made without prejudice to the effect of the University?s disclaimer to which a link appears below.
http://www.uclan.ac.uk/home/disclaimer.htm

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