October 2011 Night Skies

OCTOBER NIGHT SKIES

There is a competition going on in the early night sky at the moment with two extremely bright planets fighting for attention. It can in fact be a confusing turn of heads left and right as one tries to differentiate between the two fireballs hovering low in horizon just after sunset. Two jewels shining with a brilliant magnitude of more than -2 and are hard to miss especially since the unseasonal rain and clouds have let up over the past several days, leaving behind a background of crisp clear skies the two sparkling stars to stand out.

Jupiter shines at magnitude -2.5 in the east and looks extremely brilliant in the dark eastern horizon. Simultaneously, Venus stands out on the opposite side in the west, shining as a dazzling evening star, at more than -3.5 magnitude. Though Venus’ magnitude is one degree higher, making it two and a half times brighter than Jupiter, the two appear similarly bright because the dimmer Jupiter is in the darkened eastern sky while Venus shines in the brightened skies of the setting Sun. Jupiter reaches opposition on October 29 when the Earth, Sun and Jupiter will line up in that order, so we will see the full face of the giant planet lit by the Sun.

Jupiter continues to rise as the night goes on, while Venus sets below the horizon as the earth tilts upwards with time, swallowing up the western stars. We will chart the progress of these two diamonds of the skies over the next several months until both leave the sky by next June.

Elusive Mercury is also gearing up for attention and is currently about 3 degrees below Venus. By the beginning of next month Mercury will have closed in on Venus and the two will be parallel with the horizon 2 degrees apart, with Mercury having reached its maximum altitude. This is a good opportunity to see Mercury with the naked eyes since it will be close to a brighter, more recognizable evening star, Venus. Telescope enthusiasts will be wise to use this opportunity to detect the phases of Mercury similar to those seen in Venus, where it changes from a circular disk to a gibbous phase, half disk and eventually becoming a crescent shaped by the end of November while it is still more than 10 degrees above the horizon at sunset.

Two days after the New Moon on October 28, the Moon will form a trio with the two planets on October 28 when a very thin crescent Moon, will combine with Mercury and Venus to form an upside down “sad” face in the sky. The Moon goes on to rendevous (meet) with Jupiter on November 9 as an almost Full Moon side by side with brilliant Jupiter.

Of late we have heard of out of control satellites falling to Earth from space. Last month the 6.5 tons UARS satellite fortunately came down away from populated areas. We may not be so lucky this weekend when the ROSAT satellite is expected to fall to earth, raising once again fears of falling fragments from the firmament. Though we become immune to false alarms, especially after the anticlimax of the UARS satellite it would be good to keep abreast via the Internet about its expected entry on October 22 or 23.

The Milky Way stretches as a band of numerous stars across the evening sky, from north in the W shaped Cassiopeia, through Cygnus the large northern bird, on to Saggitarius the archer and the tail of Scorpio. The portion of the Milky Way close to Sagittarius appears as a cloud that is not a real cloud but nebulae of dense interstellar matter that is hiding from our view a powerhouse that is a supermassive blackhole at the center of the Milky Way galaxy.

This is a month of galaxies because if you are well away from city lights you might be able to make out patches of brightness that are made by our closest neighbouring galaxies, the Small Megallenic Cloud which is about 37,000 light years away can be seen close to the horizon towards the south. The Andromeda galaxy can be seen again close to the horizon in the north. It is a spiral shaped galaxy similar to our Milky Way galaxy and is about 2.2 million light years away. This makes the Andromeda galaxy the most distant object that we can see with the naked eyes. Try to locate these two galaxies using the star map.

The eastern sky has two “birds”; one to the northeast, where you will see the Cygnus with its body and wings making a wide cross, while in the southeast you will see the smaller bird Grus with its head twisted sideways. Try to become familiar with the brightest stars by their names and relative locations.

Halloween, on last day of October marks midpoint between summer and winter. It is the beginning of Autumn in the North celebrated in preparation for the coming winter blues.

The Diwali celebration on October 26, which is a festival of lights, will be given a big boost by the bright lights of the two planets Jupiter and Venus at opposite ends of the horizon.