Jupiter at its closest opposition in nearly 50 years

Today at around 13:00 UTC, the Jupiter system will be in opposition, when the planet and its attendant moons are on the opposite side of the Earth's sky from the Sun.  This means that the planet will be visible as a brilliant star in the sky all night long, rise in the east at sunset and setting in the west at sunrise.  It also means that Earth is at its closest approach to Jupiter this year, with Jupiter only 591,560,000 kilometers (367,578,000 miles) away.  From the perspective of any amateur astronomers out there, this makes it a great time to take a look at Jupiter as it is nearly 50 seconds of arc in diameter in the night sky (though let's kill any "Jupiter hoax" in the bud, Jupiter's apparent diameter is still 1/36 of the apparent diameter of the Moon).  That is large enough to pick out Jupiter's cloud bands on even the most modest of telescopes.  Despite its great distant, its large size also makes it bright enough to easily pick out in the sky.

In addition to being the closest Earth will be to Jupiter all year, this is also the closest Earth has been to the giant planet since 1963.  That is because Jupiter is close to perihelion, its closest point in its orbit to the Sun.  As you can see in the graphic above, Jupiter's orbit is slightly eccentric, and right now it is closer to the Sun (and the Earth) than it would be on the opposite side of its orbit (near apohelion), which is slightly off the graphic that is centered on the Sun.  This makes this opposition a particularly good one to check out.  Don't forget though that even if you are unable to check out Jupiter tonight, it will still be an excellent target to view for the next couple of months, though it will become more and more a planet to view in the evening.

Many planetary astronomers have been taking advantage of the current opposition to take some great images of the giant planet and its moons, like the one at left.  I love the detail you can see in this image, taken on September 20 by astronomer Damian Peach.  The southern equatorial belt is still faded and there is no indication that it will reappear anytime soon.  A great place to check for more fresh images of Jupiter is the ALPO-Japan site, where astronomers from around the world post their latest and greatest shots. Another great site to check out is Cloudy Nights forum, which includes some great discussion of how these images are taken.

So please, definitely take this chance to look up at Jupiter!