Look low above the North Eastern horizon tonight as soon as the sky is dark and you will notice a dazzling bright star. Point even a very small telescope at the ‘star’ and you will discover that you are looking at the largest planet in our solar system, Jupiter. If you do have a small telescope, look at Jupiter again tonight at 10:08 pm AEST / 11:08 pm AEDT to watch as Jupiter’s moon Ganymede (the largest in our solar system) disappears as it moves into Jupiter’s shadow.
A second reason for looking at Jupiter is the chance to see the largest storm in our solar system, the Great Red Spot. Not only is is it a very old storm (hundreds of years), it is very large at about 12,000 by 25,000 km and is big enough to hold two Earths. Sadly the colour has faded in the last few years and it should really be called the Great Salmon Spot! Given that Jupiter rotates approximately every 9 hours and 50 minutes, you have to know when to look for it. I use this handy webpage which calculates what astronomers the Great Red Spot’s transit times (i.e. when it passes across the face of Jupiter as seen from Earth). Tonight, it transits at 9:50 am.
Jupiter reaches opposition on 6 January 2014, meaning that it is at its closest to the Earth for the year. Jupiter will continue to be ideally placed for viewing over the next few months in the evening sky.
