The September 2017 night sky

Welcome to the September night sky. This month, most of the exciting planetary action takes place in the pre-dawn sky over in the east. You must be up at least one hour before sunrise to see the brilliant planet Venus just above the bright star Regulus in the constellation of Leo. They will both be about 20 degrees above the horizon and you can easily tell them apart as Venus is much the brighter of the two and Regulus, as it is a star, will twinkle noticeably.

About 10 degrees lower than Venus and just above the horizon, the two faint planets Mars and Mercury are now very close together in the pre-dawn sky, and on the 18th the Moon, two days before new, is also close.

The planet Mercury will be brighter than Mars as it is much closer, but both planets will be difficult to see in the rapidly brightening sky.

The ringed planet Saturn is still visible in the early evening heavens, but it is moving westwards now and the first quarter Moon will be close on the 26th.

The month of September is not so good for meteor showers but if you look over towards the northeast, the constellation of Auriga is rising, and the Alpha Aurigid meteor shower can produce some very fast and bright shooting stars.

The 22nd is the Autumn Equinox when the Sun crosses the celestial equator heading south and, at that time, it rises exactly in the east and sets exactly in the west 12 hours later.

The total solar eclipse of last month across America was, as expected, widely seen and publicised, and the track of totality was mostly cloud-free and even where it was not so clear the people who gathered to see were not disappointed, especially as there will be another one along in eight years.

The Moon will be full on the 6th, last quarter on the 13th, new on the 20th and first quarter on September 28.

By Clive Jackson
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Clive Jackson is the Director of the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
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To see the September Sky Map click on the pdf link below