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The 2012 International Transit of Venus



Undergraduate Thesis 2009 by Matthew Cooper

Supervised by Dr Craig Roberts


Venus in transit *




Collaborating data


Collaboration of transit observations and results

For 2012, it would be ideal to have collaboration between different observers around the world, with a common location to send observation data. This could be achieved by setting up a web site in which all observers of the 2012 transit can deposit videos of the transit, images, and any timing results collected. The web page should include a program to calculate the Astronomical Unit, or link to such a program. One example of an online site where a user can enter transit timing results and calculate a value for the Astronomical Unit is Steven van Roode’s Online Parallax Calculator, found at


A detailed set of mathematical formulae to accurately derive the AU from Halley’s method is examined in Venustransit 2004 by Heinz Blatter. The mathematics is quite complex, but the formulae take into account more variables that affect the result. This leads to a more accurate solution of the AU.


Venustransit 2004 can be found here.




Observing the transit of Venus in 2012 will be of benefit to any student or professional with an interest in astronomy, as it will serve as a modern-day spectacle showing how science has progressed since early astronomers used the transits of Venus to determine the scale of the solar system.


A modern day re-observation of the transit of Venus should build on the previous work of the astronomers who observed transits throughout the previous centuries, as well as recent observations of the last transit. It should utilise the modern technology available in order to produce a better result of the astronomical unit.


Observing the 2012 transit using video image capture through a telescope will provide a means of permanently recording the results of the transit, with the benefit of post-processing of the event to determine the astronomical unit as possible. Matching time through digital insertion will provide timing quality that will lead to better results than were possible in the times before such technology, since such methods are already widely used to accurately time occultations of planets and other stellar objects.


It is beneficial for science to have a permanent record of such an event in digital form that can be returned to and re-evaluated in the future. Such data could be highly useful for astronomical education, generating interest in astronomy and the solar system, and continuing a well-documented history of transit observations since 1639.


Further research


A potential area for further research is in calculating the astronomical unit in 2012. Formulae behind calculating this value should be carefully examined, ensuring that all assumed values about the geometry of the planets and the Sun are valid in June 2012, as much of the current literature and calculation guides available refer to the 2004 transit. Also, calculations of the Astronomical Unit (AU) are performed for one pair of locations at a time. If many places observe the transit, many different possible combinations of AU calculation are possible. An efficient method should be devised to choose pairs of observations from locations as far separated as possible, and perhaps averages made to produce a final mean Astronomical Unit value for 2012.



Quick Facts about the 2012 Transit of Venus


Transit will commence at approximately 22:00 (Universal Time)


Transit duration will be about 6 hours 40 minutes


(Times above are approximate and will vary according to observer’s location)


For Sydney:

First contact: 8:16 AM

Last contact: 2:44 PM

The transit and the distance from Earth to Sun

History of transit observations

Observation methods

Observing conditions

Collaborating data







Matthew Cooper 2009

Last modified 30 October 2009