By Duncan Lunan
The Moon will be New on December 7th, and Full on December 22nd (just after the winter solstice), shortly after its passage through the Hyades cluster in Taurus on the night of the 20th/21st.
The planet Mercury is in the morning sky, and reaches greatest elongation from the Sun on the 15th. Mercury will be near the Moon on the 5th, and Mercury and Jupiter will be less than a degree apart on the 21st and 22nd. Europe’s Bepicolombo probe to Mercury, named after the pioneer of interplanetary slingshot navigation, was launched on October 20th and is now on its way, though it will be seven years before it arrives.
Venus is bright in the morning sky, rising 4 hours before the Sun at the start of December and near the Moon on the 3rd, but drawing closer to the Sun as it moves from Virgo into Libra.
Mars moves from Aquarius to Pisces and sets around 11 p.m., growing fainter. The latest US Mars mission, Insight, landed on November 26th and will attempt to sink a probe into the soil to measure heat flow from the interior of the planet, as well as listening for ‘Marsquakes’. Mars is near Neptune on the 8th, and the Moon is near Mars on the 14th.
Jupiter is back in the morning sky, moving from Scorpius into Ophiucus, below Mercury at the start of the month and closest to it on the 21st. The waning crescent Moon is near Jupiter on the 6th.
Saturn in Sagittarius sets around 5.00 p.m., and disappears as December goes on. The young crescent Moon is near Saturn on the 8th and 9th.
Uranus moves from Aries to Pisces late in December, setting around 3 a.m..
Neptune in Aquarius sets about 11 p.m., and is quarter of a degree below Mars on the 8th.
Comet Wirtanen will be visible to the naked eye during December, though fainter than the stars of the Plough throughout. At its closest it will be 12 million km from Earth on the 16th, when it will be next to the Pleiades in Taurus, and it passes close to Capella in Auriga on the 23rd.
The Andromedid meteor shower peaks on the evening of 6th/7th December. It may be particularly active if we cross a stream of dust from the parent Biela’s Comet when it passed the Sun in 1649, and if so it will be well seen because it precedes the New Moon on the 7th. The regular Geminid meteor shower from the asteroid Phaeton peaks over the 11th/12th and will be best seen after the Moon goes down at 10 p.m..
As the Astronomers of the Future Club in Troon normally meets on the last Thursday of the month, as usual there will be no formal meeting in December, but instead there will be a social night on Sunday 16th. For details contact Club Treasurer Duncan Lunan on 01292-864764.
“Starfield, science fiction by Scottish writers”, edited by Duncan Lunan, is available from the publishers at https://www.shorelineofinfinity.com/product/starfield. Duncan’s recent books “Children from the Sky”, “The Stones and the Stars”, “Incoming Asteroid!” and “The Elements of Time” are available from the publishers, on Amazon or through booksellers; details are on Duncan’s website, www.duncanlunan.com