By CLIVE JACKSON [email protected]
Clive Jackson is the Director of the Astronomical Observatory of Tavira (Sitio do Malhão, Tavira) and the Camera Obscura (next to the Castle in Tavira), specialising in education and public outreach.
This is the month when the constellations of summer vanish from view to be replaced with those of the deep dark winter.
The first sign of this is when you can see the pretty little star grouping of the Seven Sisters over in the east before midnight. Also on the north-eastern horizon the bright yellowish star Capella is visible. This is one of the brightest stars in the northern hemisphere and when it is low in the sky, it sparkles with every colour of the rainbow and it is in the constellation of Auriga the charioteer. Prehistoric civilizations in Europe placed special emphasis on these two objects in the pre winter sky, probably because of their role as predictions of the coming gloom of winter.
The giant planet Jupiter is still well visible in the evening sky over in the southwest in the constellation of Capricorn. In 2010, Jupiter moves into the constellation of Aquarius, and this planet spends approximately one year in each zodiacal constellation and takes 12 years to complete one orbit of the Sun.
Over in the north, the Pole star is still there in the same position in the sky as it is month after month. It is in fact the only object that doesn’t move during the night. The whole sky rotates anticlockwise around the point in the night sky where the Pole star is at the moment and the grand constellation of Ursa Major moves around the Pole every 24 hours. In October, this constellation will be seen during the early evening to be right on the northern horizon, and from southern Portugal, parts of it will dip below this horizon for a few hours before rising up into the night sky once more.
The Moon is full on October 4, last quarter on October 11, new on October 18 and first quarter on October 26.
Clive Jackson is the Director of the Astronomical Observatory of Tavira (Sitio do Malhão, Tavira) specialising in education and public outreach, and the Camera Obscura (next to the Castle in Tavira), Tel: 281 321 754, Fax: 281 324 688 Email: [email protected], http://www.cdepa.pt