In 2009, the planet Jupiter will experience an equinox (it occurs only every six years) allowing the observation from Earth of mutual occultations and eclipses between the Galilean satellites. We will take the opportunity of the "International Year of Astronomy 2009" to encourage every one to look at these satellites and to make astronomical observations.
These satellites are very easy to observe and the mutual phenomena are accessible to amateur astronomers, to students and to anyone using even a small telescope. These phenomena are not only spectacular and easy to see, they are also rich in scientific information. Observations will allow us to improve our knowledge of the Galilean satellites of Jupiter, objects as large as the planets Mercury or Mars: Io and its volcanoes, Europa and its ice crust, Ganymede and Callisto.
Then we call for more than observations only for fun: we also call for some more serious observations to be made according to some rules, simple but rigorous to be followed by the observers who have the material and the possibility to record such events. The data will be gathered and used for scientific purpose. Since the phenomena occur only from April to December 2009, we need a large worldwide network of observers to record as many events as possible. Observations have already started and some observers put their observations on YouTube at the address: http://www.youtube.com/watch?v=sFDwkMb6Lpw In these videos is possible to see exactly what is observed during such events.
We intend to list all the participating observers who send in valuable data in a final publication in an international journal as was been done in the past after previous campaigns of observations with amateur astronomers.
More explanations are available at: http://www.imcce.fr/hosted_sites/ama09/phemu09_en.html
We would be grateful to the National IYA2009 nodes if they would inform all the amateur astronomers, students and high schools able to make astronomical observations.