Thursday, October 27, 2011

Jupiter at Opposition October 29, 2011

This October 29, Jupiter will reach the closest to earth, making observation excellent on cloudless nights. It is the closest approach the planet will ever get to earth between the dates of 1963 and 2022, so now is the time to study the king of the planets. On this day, earth will pass directly in between the Sun and Jupiter, making Jupiter the brightest, becasue it's closest. Although on this date the planet will be the brightest, it will be more noticed in November due to its movement in the sky. Currently, this planet is about 35 degrees from the horizon in the east, and the Galilean moons are very easy to view - even with binoculars.

Jupiter, taken by the Cassini space probe

Shining at magnitude -2.9, Jupiter is in Pisces and is 49.7 arc-seconds across. At 18:44:21 UT, Jupiter is at greatest opposition, being 3.96976 AU (Astronomical Units, distance of earth to sun, or 93 million miles) from the planet. This is 369,012,245.45797 miles away, respectively. What times can I see Jupiter? This is an excellent question - Jupiter is at opposition, therefore meaning that Jupiter will be visible all night. (Even when the moon is full, Jupiter is still bright and beaming!).

Jupiter, as seen by the Cassini space probe (the back spot on the planet is Europa's (moon) shadow)
Where Jupiter is in relation to the constellations

Viewing the Galilean Satellites

As some readers might note, Jupiter's moons are a big point of interest here at Astronomical Events Calendar. (We have even a blog dedicated to them). With just simple binoculars, you can make out all for of the Galilean moons: Io, Europa, Ganymede, and Callisto. The past few nights, I have seen the moons fairly easily and you can too. But how do I know which moon is which? As a general rule of thumb, the innermost moon is Io, the second Europa, then Ganymede, and Callisto's orbit is the farthest; all these moons, though, are at different positions and therefore hard to discern without a very strong telescope lens (you can tell by color, then) or a map of where the moons will be.

Sky&Telescope provides a "wobble*" map, showing where these moons will be in relation to Jupiter. Below are some pictures of where these moons will be positioned on certain dates.

Jupiter will be visible in the sky through the rest of 2011, but note that it will be getting dimmer. Note that Jupiter will be the closest to earth only this year until 2022 again, and keep an eye on the glorious moons of our favorite planet: Jupiter!

*for November

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Credit: NASA