ASTRONOMY GUIDE TO THE NIGHT SKY – December 2021

Astronomy

ASTRONOMY GUIDE TO THE NIGHT SKY – December 2021

With the Newbury Astronomical Society

The chart above shows the night sky at 20:00 on 15th December 2021

Click on the chart to enlarge and click to the side of the chart to close

The chart above shows the night sky looking south at about 21:00 GMT on 15th December.  West is to the right and east to the left.  The point in the sky directly overhead is known as the Zenith and is shown (in red) at the upper centre of the chart.  The curved brown line across the sky at the bottom is the Ecliptic or Zodiac.  This is the imaginary line along which the Sun, Moon and planets appear to move across the sky.  The brightest stars often appear to form a group or recognisable pattern; we call these ‘Constellations’.

Constellations through which the ecliptic passes this month are: Aquarius (the Water Carrier), Pisces (the Fishes), Aries (the Ram), Taurus (the Bull), Gemini (the Twins) and Cancer (the Crab).

The Summer Triangle that dominates the Summer Sky and was described in detail in September issue of this magazine is now moving over the western horizon.  The triangle is defined by three obvious bright stars: Deneb in the constellation of Cygnus, Vega in Lyra, and Altair in Aquila.

Prominent is the southern sky is the constellation of Pegasus (the Winged Horse).  The main feature of Pegasus is the square formed by the four brightest stars.  This asterism (shape) is known as the Great Square of Pegasus.  The square is larger than might be expected but once found is easier to find again.  There is a very nice Globular cluster in Pegasus it is known as Messier 15 (M15).  It is a lovely sight to see in a telescope.

Moving into view in the southern sky is the constellation of Taurus (the Bull).  The most obvious star in Taurus is the lovely Red Giant Star called Aldebaran.  It appears slightly orange to the ‘naked eye’ but it is very obviously orange when seen using binoculars or a telescope.  Aldebaran is located at the centre of the ‘flattened’ X shape formed by the brightest stars in Taurus.  At the end of the top right (upper west) arm of the ‘X’ is the beautiful ‘naked eye’ Open Star Cluster Messier 45 (M45) known as the Pleiades (or the Seven Sisters).  It really does look magnificent using binoculars.

Following Taurus is the constellation of Gemini (the Twins).  The two brightest stars in Gemini are Castor and Pollux and they are named after mythological twins.  To the north of Taurus is the odd pentagon shape of Auriga (the Charioteer).  Dominating Auriga is the brilliant white star Capella which is almost directly overhead.  For those with a telescope there is a line of lovely open clusters to search out in Taurus and Auriga.  These are M35 in Taurus and M36, M37 and M38 in Auriga.

To the south of Taurus is the winter constellation of Orion (the Hunter).  Orion is easily found by looking for his very obvious three stars of his belt.  Orion will be the constellation of the month in the January Magazine.

To the east (right) of Taurus is the rather indistinct constellation of Cancer (the Crab).  The stars of Cancer are quite faint and can be difficult to discern especially in a light polluted sky.  It is really worth searching out Cancer using binoculars or a telescope to see the Open Cluster M44 (the Beehive Cluster).  M44 is older and further away than M45 (the Seven Sisters) so is fainter than M45 but still looks lovely.  It has a group of stars that resemble an old straw Beehive with bees around it.

The Ecliptic was low in the sky during the summer months so the Moon and planets appeared close to the southern horizon.  Saturn and Jupiter are well placed in the early evening but steadily moving towards the western horizon.  The outer ‘Ice Giant’ planets Neptune and Uranus are still fairly well placed in the evening for those who are fortunate enough to have access to a telescope.  Due to their low altitude, the planets have not been at their best for observation this year.  The thick, murky and turbulent air has caused the planets to appear quite unsteady.

Where to find the planets this month

Mercury is not well placed this month.

Venus is visible in the early evening in the west but it is very low and close to the horizon.

Mars is too close to the Sun and is not observable.

Jupiter is very bright in the south west during the early evening but moving towards the western horizon.

Saturn is located to the west of Jupiter and moving towards the south western horizon.

Uranus can be found in the south east in the early evening but really needs a telescope.

Neptune is located in the south but will need a telescope to see it.

 

Follow this link to see the full ‘Monthly What’s Up’ guide to the night sky:

http://naasbeginners.co.uk/Whats_up/2021_2022/December2021.htm

To see a full version of this article and a guide to the night sky with charts, read the Newbury Astronomical Society (NAS) – Monthly Magazines for Beginners on the Beginners website at: www.naasbeginners.co.uk.

All meetings of the Newbury Astronomical Society have been cancelled due to the Coronavirus.  However virtual meetings will continue on-line using Zoom.  Check the website above.

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