The Venus Transit 2004
... Photos by Themes
Venus' Aureole
Quite a few observers of the Venus Transit remarked upon a rare optical phenomenon which could be perceived at the moment of the second and third contacts. However, unlike the infamous "Black Drop" effect, "Venus' Aureole" could only be seen under very good observing conditions and with excellent telescopes. It was described as a "ring of light" along the perimeter of Venus' black disc and extending beyond the solar limb. Some observers talked about "Venus' horns", stretching outwards from the two points where Venus' disc intersected that of the Sun.
This aureole was first described by the famous Russian natural scientist Mikhail Vasil'evich Lomonosov (1711 - 1765) in his "Apparition of Venus on the Sun, as observed from the Imperial Saint-Petersburg Academy of Sciences on May 26th, 1761". He correctly interpreted the phenomenon as the refraction of the sunlight in an atmosphere surrounding Venus and considered this as additional support of his conviction that there are many other inhabitable worlds beyond the Earth.
A fictive observer on the Moon would see the same phenomenon - an "Earth Aureole" - when the Earth's disc progressively covers the Sun at the time of a lunar eclipse. It is exactly for this reason that the Moon appears very red during a total lunar eclipse: the only sunlight that reaches the Moon when it is entirely inside the Earth's shadow is that passing through the Earth's atmosphere which "removes" most of the blue light.
The VT-2004 Photo Archive contains a good number of photos, both from professional and amateur telescopes, that show the aureole phenomenon at the beginning and at the end of the Venus Transit. Some of these photos have been collected on this thematic page.
Other photos and videos on which Venus' Aureole is well visible are available at the websites of the Dutch Open Telescope (DOT) and the Swedish 1-m Solar Telescope (SST), both located on the Canary Islands (Spain).
All photos on this page may be downloaded and used, provided the photographers (authors) and the VT-2004 programme are indicated as source.
Venus' Aureole at the Second Contact | |
| TRACE Image of Venus Transit (Ingress) [512 x 513 pix - 184k] | Venus' Ring of Light at Ingress [561 x 764 pix - 59k] |
| Venus' Faint Ring [800 x 600 pix - 121k] | Aureole Effect [556 x 591 pix - 54k] |
Venus' Aureole at the Third Contact | |
| Venus Transit - The End [648 x 514 pix - 27k] | Venus Transit - The End [648 x 514 pix - 21k] |
| The Atmosphere of Venus [420 x 390 pix - 37k] | Third Contact - Animation [Animated GIF - 430 x 428 pix - 1020k] |
| Venus with Atmospheric Ring at Third Contact [320 x 240 - 4k ] | Venus' Atmospheric Ring [979 x 882 pix - 66k] |
| Aurora around Venus [1255 x 959 pix - 339k] | "Ring of Light" - Sharpest Image [572 x 810 pix - 71k] |
| "Ring of Light" in Late Stadium [1300 x 440 pix - 76k] | Venus' Atmosphere [1000 x 802 pix - 53k] |
| "Ring of Light" in Very Late Stadium [1000 x 750 pix - 103k] | |
