Welcome to the October night sky. Shortly after sunset over in the west, a bright star-like object will be seen – this is planet Venus.
On the 29th of the month, Venus will be at its greatest elongation from the Sun at 47 degrees and, therefore, it can be seen in a truly dark sky. At this time, Venus may be able to cast a faint shadow due to its brilliance.
Through a small telescope, the planet will display a 50% phase, or half Moon shape. Despite Venus being similar in size to the Earth and relatively close to us in astronomical terms, no details can be seen easily on the planet as it’s covered with a thick dense white atmosphere 90 times the pressure of our own.
On the evening of the 9th, the crescent Moon will be seen just above Venus. This will be a pretty sight of the Moon and the evening star together.
There are four notable meteor showers in October. The first two are both on the same night, the 7th. They are the Piscids that are slow in their flight across the night sky and the Draconids that are faster and are dust from the tail comet Giacobini Zimmer, discovered in 1900.
On the 19th, we have the Epsilon Geminids and, on the 21st, the normally reliable Orionids from the tail of Halley’s comet. These last two showers happen at close to full Moon time, so only the brightest meteors will be seen, although the Orionids can produce fireball meteors.
The gas giant planets Jupiter and Saturn are still well visible in the south-southwest at nightfall, with Jupiter being much the brightest of the pair. Both these planets are still in the constellation of Capricornus. Jupiter will leave this constellation soon and will enter the constellation of Aquarius. Saturn is much slower moving and will stay longer in Capricornus.
The three stars of the summer triangle have now moved westwards in the evening sky and Vega, being the brightest of these stars, is now close to overhead in mid-northern latitudes.
With the clocks going back on Halloween, the cool nights will get darker much earlier and, with the Moon out of the evening sky at the end of the month, it would be a good opportunity for dark-sky stargazing.
The Moon is new on the 6th, first quarter on the 13th, full on the 20th and last quarter on October 28.
By Clive Jackson
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Clive Jackson is the director of the Camera Obscura attraction (next to the Castle in Tavira), specialising in education and public outreach.
281 322 527 | [email protected] www.torredetavira.com
To see the October Sky Map click on the pdf link below