In Vardø, a very successful observation of the Venus transit was made in 1769. The Hungarian astronomer and Jesuit, Maximilian Hell, observed the transit from Vardøhus festning in Finnmark. Hells observations made it possible to estimate the solar parallax which made it possible to calculate the average distance between Earth and Sun. Hell also estimated the values to respectively 8°8' and 149,5 million kilometers – amazingly precise! Today, the values are known to be 8°79'15" and 149.450.000 kilometers.
by Anne Mette Sannes
Diagram showing Venus transits and the angel between the orbits of Venus and Earth
Illustration: Wikipedia
Maximilian Hell observed the Venus transit in 1769 from Vardø, Norway
Photo: Wikimedia
Unfortunately, it was not possible for Hell to estimate the exact time for the transit because of the black-drop-effect – a phenomenon occurring while the planet is located near the Sun's limb. The effect was early interpreted as evidence for an atmosphere around Venus. Later, it is observed that also Mercury – which in fact does not have an atmosphere – gives rise to the same effect during transit. The cause and extent of this phenomenon are still debated, but in 2004 the effect was documented by photos. The phenomenon is probably due to the extreme contrast in brightness between Venus and the Sun in addition to turbulence in the Earths atmosphere.
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Major celestial events in Norway 2010-2015