The Winter Hexagon

The cold is making its way into our bones and we all know that Winter is bearing down.  The Winter constellations are making their way into the sky and they are a beautiful wonder to behold.  Grab the opportunity of clear skies to see Orion and Taurus with the Pleiades sparkling brightly above with the Hyades sitting a bit lower.  The Orion Nebula, further south, will put on a magnificent show as always.  

There are six bright stars high in the sky during Winter that form a hexagon.  It sits straddling the Celestial Equator with most of its area in the North.

Rigel (Beta Orionis) - Rigel is a beautiful blue-white B class star that sits as the southwestern leg of Orion.  It is the seventh brightest star in the sky and forms a double star visible in moderate sized telescopes.  A very large star it extends to more than 100 times the radius of our own Sun.

Aldebaran (Alpha Taurii) - Aldebaran is often referred to as the angry red eye of Taurus the bull.  It is a class K star and shines through to us as an orange/red colour.  It sits in the Hyades star cluster which means put it in your binoculars and be amazed!

Capella (Alpha Aurigae) - Capella is a star that stays above the horizon for us Calgarians throughout the year.  It should appear to have a yellow hue when viewed with optical aid.  It is the brightest star in the constellation Auriga (The Charioteer) and the third brightest star in the northern celestial hemisphere.

Pollux (Beta Geminorum) - Pollux is one of the twin stars of Gemini, the other being Castor.  Pollux is an orange class K star that is nearly ten times larger than the Sun.

Procyon (Alpha Canis Minoris) - Procyon is south of the celestial equator and is the eighth brightest star in the sky.  It sits in the small dog constellation known as Canis Minor.  I always notice it shining brightly with Beta Canis Minoris a short distance to the North.  It is one of our solar system's closest neighbours at just over 11 light years away.

Sirius (Alpha Canis Majoris) - Sirius.  The brightest star in the sky with an apparent magnitude of -1.46.  It is also known as the 'Dog Star' as it shines brightly in Canis Major.  The white looking star is even closer than Procyon at just over 8 light years away.

The hexagon formed with these stars at the corners is depicted below.

Winter Hexagon

Another asterism in the Winter sky that some people like to talk about is the Winter Triangle.  I find it much less exciting but I suppose it must be discussed.  It is formed with Sirius and Procyon from the hexagon and also includes Betelgeuse, the red giant of Orion.  The triangle is shown below.

Winter Triangle

The hexagon and triangle start to come up later in the evening throughout November.  They will play a critical part of the night sky all the way through until Spring.  If you are out during the Winter and not freezing, see if you can pick out all six stars of the great hexagon!