Venus Transit movie shows perspective in viewing our Solar System

New movies of the transit of Venus on 6 June 2012, viewed from two different locations on Earth, clearly show the parallax effects that have made Venus transits so important historically. The results were presented at the European Planetary Science Congress in Madrid, Spain.

The movies compress 6 hours of observations and 5000 individual images taken by optical and solar telescopes into a 40 second video. Data gaps due to cloudy conditions produce jumps in the otherwise smooth Venus motion across the Sun disk. The observations were taken from Svalbard in Norway and Canberra in Australia, which are separated by 11600km. When the images from the two locations are superimposed, the parallax effect (which first allowed astronomers to measure the distance between the Earth to the Sun) becomes clear. Parallax means that when the transit is viewed from widely separated points on the Earth’s surface, Venus appears to follow a different path in front of the Sun’s disc. Precise observations of the duration of the transit – together with an accurate measurement of the distance between the observation points – means that the distance to Venus and to the Sun can be calculated via triangulation.

The images used in the movies were obtained by members of the European Space Astronomy Centre, which is located outside Madrid. Two of the observers, Miguel Pérez Ayúcar and Michel Breitfellner are on the science operations planning team for the Venus Express satellite, which has been orbiting Venus since 2006.

Pérez Ayúcar said, “During the hours of the transit we were delighted by the slow, delicate, gracious passage of Venus in front of the Sun. A perfect black circle, containing a world in it, moving in front of its looming parent star. How thankful we were to witness it. Now with these movies, we can share a sense of that experience.” Breitfellner said, “In the 18th century people realised that transits of Venus could be used to measure the distance from the Earth to the Sun. Teams of astronomers were sent all across the world to measure this effect. The 2012 transit has its own historical importance – it is the first that has occurred when a spacecraft is in orbit at Venus. Science teams are now working to compare observations of the Venus transit from Earth with simultaneous observations from Venus Express.”

Colin Wilson, Operations Scientist for Venus Express, said, “Planetary transits are not just of historical interest, they have acquired a new importance in the study of newly discovered planets around other stars. Because we cannot image exoplanets directly, it is only by studying their transits that we can discover whether they harbour liquid water or other potential ‘biomarker’ molecules like methane or ozone. The Venus transit is an example much closer to home, offering us a chance to test our understanding of how to interpret transit data. This certainly added extra interest as we watched the Venus transit in June – particularly knowing it was our last chance that we’d have to wait until 2117 to see the next one!”

SCIENCE CONTACTS

Miguel Pérez Ayúcar
European Science and Astronomy Centre (ESAC)
Madrid, Spain

Michel Breitfellner
European Science and Astronomy Centre (ESAC)
Madrid, Spain

Maarten Roos
Lightcurve Films

A reportage of the Transit of Venus at Svalbard can be seen at
https://vimeo.com/channels/ourlasttransitofvenus

MOVIE

A movie showing the observations of the transit viewed from Svalbard and Canberra can be viewed at VIMEO:
https://vimeo.com/50357146
passwd = ToVanimation2
Credit: Pérez Ayúcar/Breitfellner/Lightcurve Films
A movie showing the observations from Svalbard and Canberra superposed onto the same disk:
https://vimeo.com/50356825
passwd = ToVAnimation1

IMAGES

A. Combined images taken simultaneously (06 June 2012, 03:46:18 UTC) from Svalbard and Canberra, showing the Venus parallax effect from 2 different locations on Earth, separated by 11600km.

B. Combined images taken simultaneously from Svalbard and Canberra during the Venus Transit 2012. The image shows the Venus parallax effect from 2 different locations on Earth, separated by 11600km.

C. Combined images taken simultaneously from Svalbard and Canberra, showing the Venus parallax effect from 2 different locations on Earth, separated by 11600km.

D. Combined images taken simultaneously from Svalbard and Canberra, showing the Venus parallax effect from 2 different locations on Earth, separated by 11600km. The red line represents the apparent path of Venus across the solar disk during the 6 hour duration of the Venus Transit.

E. Beginning of Venus Transit, on 06 June 2012, 00:13:28 CEST. White light image from Svalbard Islands.

F. The Venus Transit as seen through an H-alpha solar telescope. This wavelength band shows more details of the solar disk surface. Image taken from Svalbard Islands on 06 June 2012.

Venus exiting the Sun disk during the Venus Transit, on 06 June 2012, 06:38:21 CEST. White light image from Svalbard Islands.

Third contact during the Venus Transit 2012. White light image from Svalbard Islands.

FURTHER INFORMATION

TRANSIT OF VENUS 2012
The 2012 transit of Venus began at around 22h UTC on 5 June 2012, and finished just before 05h UTC on 6 June. The actual times differ from one location in the planet to another, due to parallax. The previous one took place on 8 June 2004 (preceded by the pair of appearances on 9 December 1874 and 6 December 1882), and the next one will occur on 10–11 December 2117.

EUROPEAN PLANETARY SCIENCE CONGRESS 2012
The European Planetary Science Congress (EPSC) is the major European meeting on planetary science and attracts scientists from Europe and around the World. The 2012 programme includes more than 50 sessions and workshops. The EPSC has a distinctively interactive style, with a mix of talks, workshops and posters, intended to provide a stimulating environment for discussion.

This year’s meeting is taking place at the IFEMA-Feria de Madrid, Spain, from Sunday 23 September to Friday 28 September 2012. EPSC 2012 is organised by Europlanet, a Research Infrastructure funded under the European Commission’s Framework 7 Programme, in association with the European Geosciences Union, with the support of the Centro de Astrobiología of Spain’s Instituto Nacional de Técnica Aeroespacial (CAB-INTA).

Details of the Congress and a full schedule of EPSC 2012 scientific sessions and events can be found at the official website: http://www.epsc2012.eu/

EUROPLANET
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