Winter Constellations of the Northern Hemisphere

Winter Constellations
Image Credit: Carolyn Collins Petersen

While northern hemisphere observers can observe a total of 30 constellations at various times of the year, there are seven constellations traditionally associated with the winter months, headed by Orion, with its nearby constellations including Canis Major, Gemini, Taurus, Perseus, Eridanus, and Cetus. In addition, there are a further five constellations that are visible throughout the whole year because they are north circumpolar and therefore appear to be orbiting the North Star (Polaris), these being Cassiopeia, Cepheus, Draco, Ursa Major, and Ursa Minor.

In this post, the seven northern winter constellations are therefore presented in an easy-to-digest format for quick reference, with one prominent deep-sky object (DSO) highlighted for each constellation, as well as a reference to other objects of interest , all of which are visible using modest amateur equipment. More in-depth studies of each individual constellations can then be found by following the links provided.

Let us start our tour of the northern winter constellations.

Orion

• Best seen: At 21:00 (9 PM Local Time) during the month of January
• Coordinates: Between latitudes +85° and -75°
• Messier objects: M42, M43, M78
• Brightest star: Rigel (Beta Orionis) with an apparent magnitude of 0.18
• Stars with known planets: 10 stars with 13 planets between them
• Neighboring constellations: Eridanus, Gemini, Lepus, Monoceros, and Taurus

Orion Nebula

The Orion Nebula (M42) is situated in the middle of Orion’s sword, and although it appears as a stellar object, a closer inspection reveals it to be a diffuse glow even without optical aid. Situated 1,350 light-years away, M42 is actually a vast star-forming region called a nebula, which becomes more apparent when viewed through 10×50 binoculars, when its central region becomes obvious, together with fainter nebulosity stretching outwards as two wings.

Orion Nebula
Image Credit: Wikisky

M42 measures around 24 light years across, and contained within it is the famous Trapezium asterism, made up of four very hot and massive stars which illuminate and heats up the nebula’s surrounding gas. This quadrangle of stars can easily be split using a 3.1-inch low/medium telescope.

Other notable deep-sky objects (DSOs) in Orion includes the bright red giant star Betelgeuse (Alpha Orionis), the famous Horse Head Nebula, De Mairan’s Nebula (M43), and Orion’s Belt, consisting of three bright stars in a straight line marking out the “waist” of the Hunter. Two meteor showers, the Orionids and the Chi Orionids, have their radiants in the constellation.

Perseus

• Best seen: At 21:00 (9 PM Local Time) during the month of December
• Coordinates: +90° and -35°
• Messier objects: M34, M76
• Brightest star: Mirfak (Alpha Persei) with an apparent magnitude of 1.79
• Stars with known planets: 6 stars with one planet each
• Neighboring constellations: Andromeda, Aries, Auriga, Camelopardalis, Cassiopeia, Taurus, and Triangulum

The Double Cluster (Caldwell 14, NGC 869 & NGC 884)

Described by Greek astronomer Hipparchus (190-120 BC) as a patch of light, these bright clusters can be seen as a single object to the naked eye, with binoculars or a telescope required to observe each individual grouping of stars. They are located about 7,500 light years away, and are approaching us at a speed of 39 km/sec.

NGC 869 & NGC 884
Image Credit: Michael Fulbright – MSFAstro.net

NGC 884 (left) and NGC 869 (right) are relatively young at just 12.5 million years old, and contain more than 200 stars each, including around 300 blue-white supergiants, and several orange-red stars.They are also enveloped with an extensive halo of stars, which raises the structure’s total mass to at least 20,000 solar masses.

Perseus is also home to the California Nebula (NGC 1499), and the Little Dumbbell Nebula (M76). Two meteor showers, the Perseids and the September Perseids, have their radiants in the constellation.

Taurus

• Best seen: At 21:00 (9 PM Local Time) during the month of January
• Coordinates: Between latitudes +90° and -65°
• Messier objects: M1, M45
• Brightest star: Aldebaran (Alpha Tauri) with an apparent magnitude of 0.85
• Stars with known planets: 10 stars with 12 planets between them
• Neighboring constellations: Aries, Auriga, Cetus, Eridanus, Gemini, Orion, and Perseus

M45 (The Pleiades Cluster)

The Pleiades (M45) is arguably the most famous open star cluster in the entire sky, and along with the Hyades, another open cluster in Taurus, are located just 444 light-years and 153 light-years distant, respectively, making them the closest open clusters to Earth. In Greek mythology, the titan Atlas had seven daughters called the Pleiades, and a further five daughters by another mother called the Hyades.

Hyades and Pleiades

To the naked eye, 7 stars are visible in the Pleiades (right) and at least 15 stars in the Hyades (left), rising to many dozens with the use of good quality binoculars. Note that the bright orange star Aldebaran is a foreground star, and does not form part of the Hyades cluster.

Taurus also contains several other famous deep sky objects (DSOs), among which are the Crab Nebula (M1), Hind’s Variable Nebula (NGC 1555), and the Merope Nebula (NGC 1435). Two meteor showers, the Beta Taurids and the Taurids, have their radiants in the constellation.

Canis Major

• Best seen: At 21:00 (9 PM Local Time) during the month of February
• Coordinates: Between latitudes +60° and -90°
• Messier objects: M41
• Brightest star: Sirius (Alpha Canis Majoris), with an apparent magnitude of -1.46
• Stars with known planets: 7 stars with 10 planets between them
• Neighboring constellations: Columba, Lepus, Monoceros, and Puppis

Messier 41 (NGC 2287)

Canis Major contains only one Messier object, M41, which is found just south of the night sky’s brightest star Sirius, and the orange giant Nu2 Canis Majoris. This bright open cluster is found 2,300 light years away and contains more than 100 stars spread out across an area bigger than the full Moon, with at least 6 resolvable in a pair of 10×50 binoculars. A 4-inch telescope, however, will reveal 50 or more stars streaming outwards from the cluster’s centre.

Messier 41 and Sirius

The only other notable deep sky object (DSOs) in Canis Major that is readily visible with amateur equipment is Thor’s Helmet (NGC 2359), a planetary nebula resembling the Norse thunder god’s winged headgear. No meteor showers are associated with Canis Major.

Cetus

• Best seen: At 21:00 (9 PM Local Time) during the month of November
• Coordinates: Between latitudes +70° and -90°.
• Messier objects: M77
• Brightest star: Deneb Kaitos (Beta Ceti), with an apparent magnitude of 2.02
• Stars with known planets: 21 stars with 27 planets between them
• Neighboring constellations: Aquarius, Aries, Eridanus, Fornax, Pisces, Sculptor, and Taurus

Messier 77 (NGC 1068)

The constellation Cetus may be the night sky’s 4th biggest constellation, covering 2.985% of the northern sky, but it contains only one Messier object, M77, which is a barred spiral galaxy 100,000 light-year across and situated 47 million light-years from Earth. The face-on galaxy has a bright core, making it a relatively easy target to locate for large binoculars of 15x70s and above, while a small 3.1-inch telescope will then resolve M77 into a ball of fuzzy light with a marginally brighter central area.

M77
Image Credit: Dieter Willasch (Astro-Cabinet)

The constellation’s only other claim to fame is the fact that three meteor showers, the October Cetids, the Eta Cetids, and the Omicron Cetids have their radiants in the constellation. It is perhaps worth noting that Cetus, along with Eridanus, another constellation on this list, inhabits a region of space that is commonly known as the Water, due to its close proximity to other constellations whose names also involve aquatic themes.

Eridanus

• Best seen: At 21:00 (9 PM Local Time) during the month of December
• Coordinates: Between latitudes +32° and -90°
• Messier objects: None
• Brightest star: Achernar (Alpha Eridani) with an apparent magnitude of 0.445
• Stars with known planets: 17 stars with 20 planets between them
• Neighboring constellations: Caelum, Cetus, Fornax, Horologium, Hydrus, Lepus, Orion, Phoenix, Taurus, and Tucana

Witch Head Nebula (IC 2118)

Located about 1,000 light years away, this nebula reflects the light of the bright star Rigel in neighboring Orion, but it still requires a dark sky in order to see this large but faint elongated object. Under optimum viewing conditions, a 10×50 binoculars will help reveal a wide field-of-view of this large nebula, with a telescopes then resolving more of its nebulosity, but only a much smaller portions at a time. Note that the blue color of the nebula is not because of Rigel’s blue light, but because the dust in the nebula reflects blue light more efficiently than any other color.

Witch Head Nebula
Image Credit: Glenn LeDrew

Elsewhere in Eridanus, a telescope will reveal a number of other deep-sky objects (DSOs), including NGC 1300, a beautiful barred spiral galaxy with an abundance of blue and red supergiant stars found 61 million light-years; with another deep-sky object of interest being the inclined spiral galaxy NGC 1332.

Gemini

• Best seen: At 21:00 (9 PM Local Time) during the month of February
• Coordinates: Between latitudes +90° and -60°
• Messier objects: M35
• Brightest star: Pollux (Beta Geminorum) with an apparent magnitude of 1.14
• Stars with known planets: 9 stars with one planet each
• Neighboring constellations: Auriga, Cancer, Canis Minor, Lynx, Monoceros, Orion and Taurus

Eskimo Nebula (NGC 2392, Caldwell 39)

Apart from the bright stars Castor and Pollux, the constellation Gemini also contains the Eskimo Nebula (NGC 2392), which was the first object imaged by the Hubble Space Telescope after the repair mission of December 1999. Situated 2,870 light-years away, NGC 2392 was formed when a Sun-like G-type star blew off its outer layers, with the object now resembling a face surrounded by a fur-lined parka hood. The Eskimo Nebula can be seen with a small telescope, with a more powerful Meade 14″ used to take the image below.

Eskimo Nebula
Image Credit: astrobruce.weebly.com

Other notable deep sky objects (DSOs) in Gemini include M35 (NGC 2168), a fairly conspicuous star cluster, the Jellyfish Nebula, the Medusa Nebula, and Geminga, a neutron star. Two meteor showers, the Rho Geminids and the Geminids, have their radiants in the constellation.

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