Go out any clear evening in December and look east around 7 or 8 pm. You’ll see a dazzlingly bright star which is, in fact, the planet Jupiter. Earlier this week (Dec. 3) the giant planet was at opposition with the Sun. In other words, the Sun and Jupiter were in opposite directions in the sky as seen from Earth. While the Sun is highest in the sky around 12 noon, Jupiter is best seen at 12 midnight. If you could look down on the Solar System from above, you would see that the Sun, Earth and Jupiter are lined up (in that order).
For amateur astronomers, this is the perfect time to observe Jupiter because it is closest to Earth and is visible all night long. Jupiter’s distance is currently 4.07 AU from Earth and 5.05 AU from the Sun. Compare this to Jupiter’s position six months from now when it is in conjunction with the Sun and hidden in the solar glare. It will then be 6.14 AU from Earth and 5.12 AU from the Sun (see: Jupiter 2012 for a complete ephemeris of the planet during the year).
Jupiter is the largest planet in the Solar System and has an equatorial diameter of 143,000 kilometers. This is 11.1 times Earth’s diameter. Even giant Saturn is just 84% the diameter of Jupiter. Of course, if we compare Jupiter to the Sun, it’s diameter is a mere 10% of the Sun’s. At a mean distance over five times greater than Earth’s from the Sun, Jupiter takes 11.86 years to complete one orbit around our star.
Jupiter currently subtends an angle of 48.5 arc-seconds – the largest of the year. Even a modest telescope will reveal Jupiter’s disk, its cloud belts (appearing like pale stripes), and its four biggest moons Io, Europa, Ganymede, and Callisto (appearing like bright stars aligned in the same plane as Jupiter’s cloud belts).
The movie above is time-lapse of Jupiter, taken by NASA’s Voyager 1 spacecraft as it approached the planet in February 1979. It covers a period of 95 hours, and and shows how rapidly Jupiter’s clouds rotate. It also features appearances of three of Jupiter’s innermost moons: Io, Europa and Ganymede. You can also see the shadows of the moons race across Jupiter’s clouds tops.
Although I’ve done a lot of astrophotography, none of it involves close-ups of the planets. However, Damian Peach, an amateur astronomer from southern England is a master of high resolution planetary imaging. You’d be excused if you mistake Peach’s images for something shot by NASA’s Voyager. His images are that good! Take a look at some of Peach’s recent images of Jupiter.
Even without a telescope, the view of Jupiter in Taurus is beautiful. Below Jupiter is the the v-shaped group of stars called the Hyades. The bright orange star in the Hyades is Aldebaran. To the upper right is a tiny dipper-shaped star cluster known as the Pleiades. I’ll have more to say about the Pleiades in a future blog.
Over the course of the next few months, Jupiter will slowly change position against the background stars of Taurus. And just in case you’re wondering, the placement of Jupiter in Taurus has absolutely no significance on the life and affairs of Earth’s inhabitants. Astrology has been around for thousands of years and yet, there is no scientific evidence to support any of its principles, postulates or claims. To put it more colloquially, astrology is a bunch of baloney! Read all about it in Phil Plait’s blog on astrology.
In the meantime, go out tonight and enjoy the view of Jupiter and Taurus.