If you look out the window this month and notice that the sun is setting in a different place every day, don't worry, the earth is not spiralling out of orbit: it's tilting toward the sun to welcome the season of autumn, beginning 23 September.

This means a new set of stars and constellations will make their debut. A couple of hours after sunset, you will see the Milky Way stretching diagonally across the night sky (you may need to wait for a load-shedding night to see this). Make sure to pull out a set of binoculars and observe this band of stars because it contains some fantastic constellations. You will see the W-shaped Cassiopeia, the Great Summer Triangle, Sagittarius and Scorpios. In the eastern horizon, just below Cassiopeia, don't miss the constellations of Andromeda and the square-shaped Pegasus. The Big Dipper will be only partly visible in the north-western skies, but the kite-shaped Bootes and the man-shaped Hercules should be clear.

There will be a full moon on 4 September, also called the 'Harvest Moon' because it helps farmers harvest past sunset.

Planets
Mars will rise in the north-east just before midnight but the view will be obscured late September when it is directly between the earth and the sun. The planet will drift eastwards through Gemini and head toward the bright twin stars of Castor and Pollux. You can catch a late glimpse of it again at the very end of September when it will be visible in the east just before dawn below a sparkling Venus, which should be clearly visible throughout the month.

Jupiter will be the only planet visible in the evening this month, and will descend toward the horizon as the evening passes. The planet can be best seen late in the evening when it's sitting a mere 20 degrees above the horizon. Telescope users will have a few chances to catch Jupiter's closest moons, Io and Europa, eclipsing and occulting one another on September 15, 22 and 29.

Saturn fans have less to cheer about since the planet will be invisible for some part of the month as it hides behind the sun. Since it's tilting away from the earth, its rings will lose their characteristic sheen as they reflect less of the sun's light. The last opportunity to view Saturn's rings is on 4 September at 6:45 pm. Catch the planet close to the western horizon.

kedarbadu(at)gmail.com