Welcome to the October night-sky. This is the month when the clocks go back (29th), and the nights start to darken noticeably.
Over in the northeast, the star cluster called the Pleiades, or the Seven Sisters, can now be seen well before midnight and this is an unmistakable sign of the fast-approaching winter in the northern hemisphere.
This amazing star cluster, containing hundreds of bright and faint stars, is approximately 400 light years away. Although it is called the Seven Sisters, most people see only five or six stars, but under exceptional conditions some have claimed to see as many as 14. This star cluster is only about 100 million years old, so it is unlikely to have had time to form stable planets.
Galileo Galilei viewed the Pleiades with his small telescope in 1610 and he counted 36 stars. At the same time in the evening, when the Seven Sisters star cluster is rising, you can also see, in the northeast, one of the brightest stars in the northern hemisphere of the night-sky, called Capella.
This star, when seen low down and close to the horizon, can be seen to flash all the colours of the rainbow and, when this happens, people who are not familiar with the night-sky have been known to think it could be a UFO.
Capella is 42 light years away and this makes it one of our nearest neighbouring stars. Although it is of similar colour to our Sun, it is very different as it is a close double star with two red dwarf companions on a distant orbit.
The major planets are not well visible this October, but on the 21st we have the usually reliable Orionid meteor shower with its fast, yellowish-coloured shooting stars. This meteor shower will be best seen after midnight.
The Moon will be full on the 5th, last quarter on the 12th, new on the 19th and first quarter on October 27.
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 October Sky Map click on the pdf link below