William Atkins
Monday, 11 May 2009 20:40
Science -
Space
Page 1 of 2
A rarely recorded astronomical event in our Solar System occurred recently when one of Jupiter’s moons moved directly in front of another one and Australian amateur astronomer Anthony Wesley caught it on video.
The ability for us Earthlings to see the moons of Jupiter eclipsing each other can occur only once every six years.
This six-year cycle is occurring now, in 2009, because the Earth is
passing through the orbital plane of Jupiter’s satellite system.
Therefore, the natural satellites (moons) of Jupiter are positioned one
after the other in a line. We see the ones in the outer orbits first,
with those closer to the planet further back.
And, the last time such an arrangement occurred was in 2002/03.
In 2009, this ability for us to see and record Jupiter’s moons
eclipsing each other occurs only between the months of April and
December.
On May 8, 2009, Wesley, who is located in Murrumbateman, Australia,
made the video with a digital video camera that was attached to his
13-inch telescope.
He recorded Jupiter’s moon Europa passing directly in front of Ganymede, one of its other moons.
Europa is the smallest of the four Galilean moons of Jupiter. Galileo
Galilei discovered it in 1610, just under 400 years ago. Jupiter has 63
confirmed moons in total.
Ganymede is the largest moon of Jupiter, and the largest natural
satellite of any planet in the Solar System. Galileo also discovered it
in 1610. It is the largest of the Galilean moons, which are the largest
moons of Jupiter.
The video showing the "mutual occulatation" of Europa and Ganymede (both passing in front of Jupiter) and the eclipsing of Ganymede by Europa is found on page two.
