In the Sky in December 2015

The evening sky is devoid of planetary landscapes, with one exception… Mercury. The only planet in the evening sky of December 2015, the planet of thieves and rhetoric,  appears as a bright star setting in the south-west an hour after the Sun at the beginning of the month, then moves slightly higher in the twilight, setting 80 minutes after the Sun by the end of the month. In a telescope it looks like a tiny gibbous moon; a moon between first quarter and full.

You can read about the Sky of December here. As the star patterns repeat every year and so the same stars will adorn the night sky year after year in the same month of the year. But the planets,  the wanderers of the night sky, will change their positions every day, in a dance measured by what we call ‘ephemeris‘,

Jupiter, Mars and Venus are all in the morning sky.  Saturn, the father of Gods, joins them at the end of the month, coming from behind the Sun. At the beginning of December Jupiter rises around 2:30 a.m. and reducing to 12:30 a.m. by the 31st.  It is a bright golden-coloured ‘star’ shining with a steady light.  Venus is up around 4 a.m., a brilliant object bright enough to cast shadows in dark locations.  Mars is between the two bright planets, looking like a medium-bright reddish star. Jupiter and Mars rise steadily earlier while Venus stays put in the dawn. In the second half of the month Mars is near, then passing below, the bluish-white star Spica the brightest star in Virgo. At the end of the month Saturn emerges from the dawn twilight below and right of Venus, at the bottom end of the diagonal line of planets. The crescent moon will be close to Venus on the morning of December 8th.

A small telescope shows Jupiter’s disk with its four big moons like faint stars lined up on each side. They change sides from night to night as they orbit the planet.  Jupiter is 794 million km away mid-month.

The Geminid meteor shower peaks on the morning of the 15th.  The meteors appear to come from the constellation of Gemini, low in the northeast at midnight, moving to the north by dawn. The meteors are clumps of dust from a comet, the friction from the air heats them up and makes the air around them glow.