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VENUS in transit Robert Wielinga
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Venus Evening star Goddess of love and beauty planet
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Utrecht, june 8th 2004, 05 h 20 m : sunrise
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Utrecht, june 8th 2004, 07 h 19 m : a black dot passes in front of the sun I : first contact at 07 h 19 m II: seccond contact at 07 h 39 m III: third contact at 13 h 03 m IV : fourth contact at 13 h 23 m A transit of Venus: a mini solar eclipse
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1631 1639 1761 1769 1874 1882 2004 2012 2117 2125 88888 121 ½ 105 ½ Regularity in the occurance of transits of Venus
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months 00030609 12151819 When Venus meets the earth Every the earth is overtaken by Venus
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No transit Transit! But the orbit of Venus is tilted slightly with respect to orbit of the earth around the sun (3,4 o ). Usually when Venus overtakes the earth there is no exact alignment Exact alignment: very rare! When Venus meets the earth
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jan dec feb mar apr may jun jul aug sep oct nov 1996 1998 1999 2001 2002
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19962004 2012
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Jeremiah Horrocks observes the transit of 1639
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William Crabtree (friend of Horrocks) is the seccond person to observe the 1639 transit “I beseech you, therefore, with all my strength, to attend to it diligently with a telescope and to make whatever observation you can….” Horrocks, in a letter to Crabtree
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A A B B The path of Venus acros the sun by observers A and B as seen from the earth Halley (1656-1742) proposed a method to measure the ‘immense distance to the sun’ by international coordinated observations during the transit of 1761.
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Voyage with the Endeavour Captain James Cook 1769: Tahiti
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Captain James Cook 1769: Tahiti
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The unfortunate adventures of Guillaume-Joseph-Hyacinthe-Jean- Baptiste Gentil de la Galaisière (Le Gentil) maart 1760 juli 1760 mei 1761 6 juni 1761
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mrt 1768 mrt 1770 okt 1771 aug 1766 The unfortunate adventures of Guillaume-Joseph-Hyacinthe-Jean- Baptiste Gentil de la Galaisière (Le Gentil)
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Problems in 1761 / 1769: - Weather (Le Gentil) - Longitude - The BLACK DROP effect
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CairoRodriguez Is.MauritiusNew Zealand 1874 / 1882 New hope: - Photography - Parallax of stars
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Members of the Dutch expedition in 1874 in front of their accommodation in St. Denis, Réunion Observation camp of the Dutch expedition 1874: Dutch participation !
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Exhibition in Museum Observatory Sonnenborh
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VENUS Distance to the sun: 108 million km 0,72 AU Diameter: 12.104 km (0,95 x earth) Massa: 4,7 x 10 24 kg (0,80 x earth) Temperature (surface): 490 °C Pressure (surface): 90 atmosphere
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The atmosphere is is composed mostly of carbon dioxide. There are several layers of clouds, many kilometers thick, composed of sulfuric acid.
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Mikhail Lomonosov, june 5, 1761 discovered, during a transit, that Venus has an atmosphere
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Magellan spacecraft Launched from the Space Shuttle (1989)
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Venera 13
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A partial solar eclipse: the moon covers the sun
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Mercury in transit in may 2003 sunspot
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Eclipse glasses Pinnhole projection Mirror projection
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Projection method: safe and handy! With binoculars (only use one half) or telescope
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Links: www.sonnenborgh.nl www.venusovergang.nlwww.venusovergang.nl (nog niet aktief) home.hetnet.nl/~smvanroode/venustransit www.venusovergang.be www.vt-2004.org
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