PLANETARY SHOW IN THE EVENING SKIES
PLANETARY SHOW IN THE EVENING SKIES
By Dr N. T. Jiwaji
ntjiwaji @ yahoo.com
A planetary show is taking place now in the evening skies towards the western horizon immediately after sunset from 7 pm. Go out and be amazed by the extremely bright star that is shining just above the horizon above where the sun has set in the west. This brilliant object is not a star, it is the planet Venus, which is also fondly called the Evening Star. No other star shines as brightly except the biggest planet Jupiter. Venus has been in our evening skies since March this year when it entered as an evening star in the west. Since then it has been rising steadily above the west horizon at sunset while it approaches us from its farthest distance from Earth. Venus will remain with us until March next year when it will again dip below the west horizon after it has comes closest to Earth.
At the moment you will see Venus about 30 degrees above the western horizon. Even when the sky is still bright, immediately after the Sun has just set, you can make out a sharp point of light. You can challenge yourself with your friends to compete who can first spot Venus. Young children’s eyes will often make it out more quickly because while older people will have a harder time due to changes in sensitivity of their eyes.
Once the Sun has gone down a little more, around 7 pm, you will be able to make out two other bright points above Venus. Directly above is the sharply shining Saturn while to the left and between the two planets you will see a red star which is Antares, the neck star of Scorpio constellation. You can notice that the two planets shine with a steady light while the red star twinkles. This is a good way of differentiating between planets and stars. Near the horizon, the atmosphere can interfere and can make a less bright planet such as Saturn twinkle. At the moment Saturn is high enough to avoid this disturbance.
Further above Saturn you will see another red star close to the Sagittarius constellation. This is none other than March which has been with us since March when it entered our night skies from the East.
The more interesting thing to view about the three stars is that the triangle shape made by Venus, Saturn and Antares changes visibly day by day. This is because Venus is rising quickly in the sky every day so much so that by the end of this week Venus, Saturn and Antares will form a straight line. This means you will have seen Venus moving in its orbit around the Sun while at the same time it is approaching Earth. The name planets comes from the Greek word for wanderers. They had noticed that some stars were moving across the background stars and sometimes they moved in opposite ways, hence they called such stars planets or wanderers. Saturn, Venus and Antares will be in an almost straight line on Thursday 27, Friday 28 and Saturday 29 October. Bright Venus will be in the middle while red star Antares will be lower left and Saturn will be upper right.
An even more spectacular view will be seen the following week when Venus continues to climb up the sky. New Moon is on 31 October so by 01 November a thin crescent will be seen below the Venus, Saturn pair. By Wednesday 02 November the thin crescent will settle below Saturn and will form a straight line with the bright Venus above. It will be a beautiful sight not to be missed.
Through a telescope Venus is a small object at the moment and it has gibbous (oval) shape. Since last March Venus has been approaching us from its most distant position and was seen as a small dot in a telescope. As it approaches Earth it changes phase (or shape) from small circle to larger oval (gibbous, as seen now) and when it is closest it appears much larger and in a crescent phase. This is because Venus moves in an inner orbit to ours so part of its sphere that is in darkness faces us hence its shape (or phase) changes from circle to gibbous and finally becomes a crescent while at the same time it becomes six times larger when it is closest to us.
Saturn is the most beautiful sight that you can see through a telescope. Even a modest telescope will show its rings surrounding the ball of the planet. At the moment it is tilted at its maximum angle towards us and hence offers a sight that you will remember forever. Its Moon Titan can also be seen as a tiny dot away from the rings.
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