Astronet and 'Planetary Paul' were organising a live webcast of the Venus transit from The Netherlands. Unfortunately, Planetary Paul was clouded out completely. But luckily there were many other stations around the world and from outer space that provided webcasts and live streamings of the event.
Don Pettit, flight engineer on board of the International Space Station (ISS), will photograph the Venus Transit from one of the windows of the cupola of ISS. Pettit's pictures will be posted at this Photostream.
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These geocentric times are for an observer at Earth's center. The actual contact times for any given observer may differ by up to ±7 minutes. This is due to effects of parallax, since Venus's 58 arc-second diameter disk may be shifted up to 30 arc-seconds from its geocentric coordinates depending on the observer's exact position on Earth.
Here is a list of predicted contact times and corresponding altitudes for a number of cities around the world. Here are lists of similar predictions for locations throughout Canada and the USA.
The entire transit (all four contacts) is visible from northwestern North America, Hawaii, the western Pacific, northern Asia, Japan, Korea, eastern China, Philippines, eastern Australia, and New Zealand. The Sun sets while the transit is still in progress from most of North America, the Caribbean, and northwest South America. Similarly, the transit is already in progress at sunrise for observers in central Asia, the Middle East, Europe, and eastern Africa,. No portion of the transit will be visible from Portugal or southern Spain, western Africa, and the southeastern 2/3 of South America. (Note that due to the International Date Line the Western Hemisphere will see the transit on June 5.)
NEVER LOOK DIRECTLY AT THE SUN WITH UNPROTECTED EYES - THIS MAY CAUSE TOTAL BLINDNESS WITHIN SECONDS! ALWAYS BE SURE TO USE PROPER OPTICAL FILTERS TO PROTECT YOUR EYES.
The use of #14 shade welding glass or eclipse shades will permit a large number of people who do not have specialized equipment to observe this event. However, as the planet approaches the limb of the Sun, subtleties like the black drop effect may not be discernible. Pinhole projectors are a safe, indirect viewing technique for observing an image of the Sun. While popular for viewing solar eclipses, pinhole projectors suffer from the same shortcomings as unmagnified views when Venus approaches the edges of the Sun. Small features like the black drop effect and the halo around Venus while it straddles the solar edge may not be discernible.
You may project a magnified view of the Sun through a telescope onto a surface, but the technique often has its own limitations. For example, large reflector telescopes can generate too much heat by concentrating a lot of the Sun's energy on the secondary mirror and eyepiece. Likewise, Schmidt-Cassegrain telescopes can experience too much heat build-up as the light bounces internally. Also, magnified projections usually have an exposed focal point beyond the eyepiece where bystanders could inadvertently burn themselves. Constant attention is required.
The transit of Venus is perhaps best viewed directly when magnified, which demands an appropriate solar filter over the large end of the telescope. Do not use small filters that fit over the eyepiece, for the concentrated sunlight can shatter them. The sun's energy must be attenuated before it enters the telescope. A filtered, magnified view will show the planet Venus, the "black drop" effect, and sunspots.
No matter what technique you use for viewing the sun, do not stare continuously at the sun! Always give your eyes a break.
The first astronomer to recognize the importance of observing transits of Mercury and Venus was Edmund Halley (1656-1742). It appeared to the observer, using a telescope as the lens of a camera obscura (never look directly at the Sun through a telescope!) as a black dot crossing the surface of the Sun. The first astronomers to use telescopes to observe the transit of Venus were Jeremiah Horrocks (1618-41) and William Crabtree (1610-44) in 1639.
Astronomers travelled to remote parts of the world to observe the transits of Venus in 1761 and 1769. To observe the transit of 1769, Captain Cook sailed from England to Tahiti. He discovered Hawaii and a few other places as bonuses along the way; it is not often that the side benefits of astronomical research are so apparent.
How accurate were the measurements of Cook? The "dusky shade round the body of the Planet" as he descrtibed the appearance of Venus was a problem. Intense sunlight filtering through Venus' atmosphere fuzzed the edge of the disk and decreased the precision with which Cook could time the transit. For this reason, his measurements disagreed with those of ship's astronomer Charles Green, who observed the transit beside Cook, by as much as 42 seconds.
In recent years, radio signals emitted by spacecraft as they pass behind Venus have enabled us to obtain very accurate planetary positions and masses, as well as the distance between the Earth and the Sun. Because of these results from space exploration, observing this and future planetary transits will be of less scientific importance, but they will of course continue to be great public and educational interest.
Dutch physicist Steven van Roode developed a special and free Phone App to report contact timings for a similar calculation.
Transit of Venus 2012 of the Bradford Robotic Telescope Project has an automatic algorithm for reporting contact timings. The results can be checked online.
Astronet.nl welcomes your photographs! Send your best pictures (3 at most, maximum size 1200 x 900 pixels) to:
What else is there to be seen? Look before and during ingress and during and after egress for a spectacular 'light ring' around the black silhoutte of Venus. This is caused by sunlight that is refracted by Venus' thick atmosphere. It was after observing this light ring in 1761 that Russian astronomer Mikhail Lomonósov realized that Venus is surrounded by an atmosphere.
The atmosphere of Venus can be observed simultaneously from Earth-based telescopes and from the Venus Express spacecraft. This will give a better opportunity to understand the intermediate level of Venus's atmosphere than is possible from either viewpoint alone, and will provide new information about the climatology of the planet.
The atmosphere of Venus can be studied using a spectrograph. The results of analysis of the well-understood atmosphere of Venus will be compared with studies of exoplanets with atmospheres that are unknown.
The Hubble Space Telescope cannot look at the Sun directly. But Hubble will be aimed at lunar crater Tycho and study the reflected sunlight to detect spectral fingerprints of Venus' atmosphere. This may provide another technique to study exoplanets.
Wikipedia should first investigate before they block a serious contribution! German poet, philosopher, historian and playwright Friedrich Schiller (Johann Christoph Friedrich von Schiller, 1759 - 1805) knew it:
"Mit der Dummheit kämpfen Götter selbst vergebens." (Talbot in Die Jungfrau von Orléans, III, 6)
In plain English:
"Against stupidity, the gods themselves contend in vain."
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