Winter Hexagon Constellation
The Winter Hexagon is in fact an asterism rather than a constellation. It does not have an official IAU designation and links the 6 brightest stars in each of 6 major constellations. The 6 stars are among the brightest in the northern hemisphere sky and why this formation is able to be identified despite its coverage of a large section of the sky.
The Winter Hexagon is sometimes referenced as an oval or circle. It links the stars of Rigel (Orion), Sirius (Canis Major), Procyon (Canis Minor), Pollux (Gemini), Capella (Auriga), Aldebaran (Taurus). It is considered one of the easiest formations to identify as it includes 4 of the 8 brightest stars visible from earth as well as Aldebaran at #14 & Pollux at #17.
Neighbouring constellations: Monoceros (south east), Cancer (east), Lynx (north east), Perseus (north west), Aries (west), Lepus (south)
Brightest star: Sirius, -1.46 magnitude
Stars brighter than 3 magnitude: 6
Primary stars: 6 points of the hexagon
Latitude: 15 degrees south – 45 degrees north
Northern Hemisphere Season: Winter (October – February)
Which months can you see the Winter Hexagon constellation?
The Winter Hexagon is a large asterism that covers several constellations. The western most part of the asterism rises with Taurus. The eastern most part of the asterism sets with Canis Minor and Gemini. As such it is partially visible throughout winter but completely visible from October to February. However it is best seen in the evening sky in February.
As with the winter constellations which it encompasses, it is not possible to see throughout much of the year, as it passes in the daytime sky throughout summer. Its maximum range where it is possible to see are between latitudes between +90 and -45.
Winter hexagon rising and setting times:
Best visible at 21:00 in February
For rising times refer to Taurus
For setting times refer to Canis Minor or Gemini
For Peak times refer to Orion
Trajectory: The constellation is between 45 degrees north and 15 degrees south which means that for those in low latitudes of the northern hemisphere is will pass overhead and in the southern sky, for those in higher latitudes of the northern hemisphere it will appear in the southern sky.
How to find the Winter Hexagon constellation?
Difficulty to locate: Very Easy – Difficulty to interpret: Very Easy – Locating Asterism: starting at Orion’s Belt
As each of the stars within the Winter Hexagon is bright and easily identifiable in its own right you can start from any point to identify its shape. Most commonly Orion is the starting point as it is disguishable because of the belt asterism. However at times when it is partially visible in Spring or Autumn other stars may act as better indicators.
Tracing the shape of the Winter Hexagon
The hexagon is relatively simple to identify as all six stars are similar distances from each other which allows the view to have both a directional reference and distance reference once two initial stars are identified.
Working clockwise from Rigel at Orion’s left foot:
Rigel is recognisable as the bright star perpendicular to Orion’s belt
- Sirius is south east and marks the chest of Canis Major
- Procyon is north east and marks the tail of Canis Minor
- Pollux is north and marks the head of the twins of Gemini
- Capella is north west and forms part of Auriga
- Aldebaran is south west and marks the eye of Taurus the bull
- From there return south to Rigel
This is an extremely useful asterism as in addition to identifying 6 major constellations it provides good directional bearing between these constellations for navigation during winter.
Sirius (-1.46m, 8.6ly, #1)
Sirius from the Greek word ‘scorching’ is the brightest star visible from earth with apparent magnitude of -1.46. Sirius is a dual star at a distance of 8.6 light years. It is the 5th closest star to earth (discluding the sun), but only Alpha Centaurus ahead of it is prominent. Because of its prominence the star has over 50 names across different ancient cultures, particularly in reference to dogs and its identity as the dog star. Sirius forms part of both the Winter Hexagon and Winter Triangle.
In ancient times Sirius would appear in mid to low latitudes in the northern hemisphere in mid July. Its appearance marked the beginning of the Egyptian year and was the indicator of seasonal floods. In many Mediterranean cultures the appearance of Sirius marked the ‘dog days’ where intense heatwaves would impact people and their animals and crops. Sirius has a latitude of 17 degrees south and became important for Polynesian sailors as an indicator of the path of true east-west. The star marks the chest of the dog in Canis Major.
Rigel (0.18m, 772ly, 2m suns, #7)
Rigel from Arabic word for ‘left foot’ is the 7th brightest star visible from earth with an apparent magnitude of +0.18. The star is 772 light years from earth. It is a blue supergiant 2 million times the size of the sun. Rigel forms part of the winter hexagon asterism. Rigel marks Orion’s left foot.
Aldebaran (+0.86m, 65ly, 350k suns, #14)
Aldebaran named from the Arabic for ‘the follower’ in reference to it following the course of Pleiades. It is the 14th brightest star with an apparent magnitude of +0.86. The distance from earth is 85 light years. It is a red giant, over 350,000 times bigger than the sun. The Hyades cluster is behind it, this small section of the sky is additionally luminated and draws attention to the star making it one of the most recognisable in the winter sky. Aldebaran marks the right eye of the Taurus bull.