The December night sky
By Stargazer
Another year is drawing to a close although winter does not officially begin until 22nd December. This is known as the winter solstice and marks the date when the sun transits its lowest point in the sky at noon. After this the days will become longer and nights shorter.
For those brave souls prepared to forsake the warm fireside to stick their noses into the chill of a clear December evening, the view will not disappoint! Darkness can fall as early as 5 pm and at this time the southern and eastern sky are much as they have been later on autumn evenings, with the Square of Pegasus high in the south.
Later on the king of the winter constellations Orion slowly rises above the eastern horizon but more on him next month when he is higher in the sky earlier on.
During the beginning of the month the moon will be very prominent, becoming full on the 5th. If we are blessed with clear skies as at the beginning of November, the light of the full moon high in Gemini will be very bright indeed and cast clear shadows.
Take advantage of this time for an evening walk. Later on in the month in the week or so up to Christmas, the moon will be waning and late evening skies will be particularly dark and the view of the stars will be impressive.
Between 7th – 15th December with a strong peak on 13th – 14th, the Geminid meteor shower usually produces some fine slow bright meteors from a radiant just north of the star Castor. This is one of the two brightest stars in Gemini along with Pollux. See your star atlas for further details.
The Milky Way
The Milky Way is not at its brightest this month but on a clear moonless night it can be seen running from Perseus/Auriga (almost overhead in December) through the southern part of Gemini. The winter Milky Way is less bright than that seen in the summer as during December looking south we are looking outwards to our galaxy’s rim as opposed to summer when the view is inwards to the galactic centre.
The planets continue to be well hidden from view this month but for the eagle eyed of you, Venus can be glimpsed low in the evening sky after sunset around the end of the month. However it will continue to become more prominent in the west during the new year, so again more on this in the next few months.
Have a great Christmas and enjoy the splendour of the night sky.