December Sky Notes

December’s night skies see all four giant planets, Jupiter, Saturn, Neptune and Uranus, on view for, at least, part of the night and they are joined by two of the Dwarf Planets, Pluto and Eris, although to find these, some serious observing techniques need to be applied, even with large telescopes.

The 70th Anniversary season of the Torbay Astronomical Society culminates over the Christmas period with a series of prestigious lectures from some highly regarded and inspirational speakers. 

On Thursday 4th December, Professor Chris Lintott of the BBC Sky at Night Program will give a Public Lecture at the Cavanna Hall, Torquay Boys; Grammar School entitled “100 Years of Discovery: Astronomy in 1955 and 2055” (details in Diary Dates, below). Professor Lintott is a former TBGS pupil and TAS member. 

A second talk on December 11th will be given by Dr Simon Berry, who is the Deputy Director of the new, international Square Kilometre Array Observatory, will speak about “The Biggest Eyes on the Sky: The Next Generation of Ground-based Mega Telescopes”.

Then on January 8th another former TBGS student, Professor David Southwood, who was the Director of Science Missions for the European Space Agency and a past President of the Royal Astronomical Society, will give a talk entitled “From Torquay to Titan and Beyond: Memories from a Career in the Cosmos”.

Sky Notes

Sky Schedule

Please note all times given in this article are in GMT.

Sun: Throughout December the Sun sets before 4.30 and there are just 8 hours of daylight.  The Winter Solstice (shortest day) occurs on December 21.  On this date the Earth is closer to the Sun than at any other time in its orbit.  We experience Winter in the Northern Hemisphere because the North Pole is tilted away from the Sun and its warming energy is spread over a greater area on the surface of the Earth.

Mercury:  Mercury is technically visible in the morning sky, but ruses in the growing sawn light so will be very difficult to spot.

Venus:  Venus ruses after Mercury so will not be easily visible this month.

Mars:  The red planet is not visible this month. There have been recent claims that the NASA rovers on Mars have discovered evidence of ancient life on the planet. However, on further investigating NASA’s report, what they have actually said is that they have discovered areas on the surface where the conditions are more conducive to the formation of ancient life. No definite signs of such life have been found.

Jupiter:  Jupiter is a brilliant object throughout the night, rising around 7pm and is well placed for observation by 9pm. Jupiter is currently seen against the background stars of Gemini and can be seen in the south-eastern sky. The Galilean moons can be seen with a good pair of binoculars or a small (bird-spotting) telescope.  DSLR images of the planet will also pick up the moons.  The cold winter skies (if they are clear) give a much clearer and steadier image in a telescope or binoculars making observations much more satisfying. 

Saturn: The ringed planet can be found against the stars bordering the constellation of Pisces and Cetus in the Southern sky, throughout the night. Its rings are now closed up (from our point of view) and this is why it is becoming fainter, although still a naked-eye object.  

Uranus and Neptune: Uranus is visible all night long throughout December and is seen against the background stars of Taurus. Uranus can be found below and to the South of the Pleiades star cluster.  At magnitude 5.7 it is visible in binoculars.  Look for a tiny greenish disc compared to the pinpoints which are the stars.  Neptune is seen against the background stars of Pisces and close to the planet Saturn. At magnitude 7.8 it will require large binoculars or a larger telescope to find it and an even larger telescope to discern its disc.  Neptune displays a smaller and truly blue disc compared to that of Uranus although it will appear only as a bluish star to most small instruments. 

Dwarf Planets:  As a matter of interest, the early evening dark skies also contain the two largest dwarf planets, Pluto and Eris. The only real way to be sure of seeing these is with a large telescope set up for imaging. Even then multiple images need to be taken over a period of hours – days in order to reveal the motion of these tiny, distant worlds. Pluto is found in the constellation of Capricornus, but quite close to the horizon, so will not be visible for long. Eris, on the other hand, is seen against the background stars of Pisces, just a little lower in altitude than Saturn. The dwarf planet lies slightly West of the star Alpha Piscis, commonly known as Alrescha.

Meteor Shower:  December contains a number of minor meteor showers that occur throughout the month. These are not very active and have low meteor counts but can make it worthwhile “keeping an eye out” for shooting stars against the dark, winter skies, throughout the month. There are two major meteor showers due in December. The first, which peaks on the night of 13th, is the Geminids. The Geminid shower is the only shower associated with an asteroid rather than a comet.  This asteroid is called Phaethon.  The Geminid shower can be intense, although there will be bright moonlight for, at least, part of the night. The second shower this month is the Ursids (maximum on 21st) that seem to emanate from a point in the constellation of Ursa Minor, which also contains the Pole Star.  

Comet:  The, by now, infamous comet 3I/Atlas will reach its closest approach to the Earth on December 19th.However at a distance of 1,8 Astronomical Units (about 270 Million Kilometres, it will only reach magnitude 10, at best. So it will not be visible to the naked eye or small telescopes.

Moon: The Full Moon occurs on December 4th  with Third Quarter on  11th, New Moon then follows on 20th December and First Quarter on 27th