Taurus Constellation Guide – A Horned Bull In The Night Sky

In this article, we’ll be sharing with you everything you need to know about the constellation of Taurus, including how to find it, deep space objects contained within it, and how to use it to find other night sky objects more easily.

The Constellation of Taurus

Taurus means ‘the bull’ in Latin. This constellation was known to many ancient cultures including the Babylonians, ancient Egyptians, and ancient Greeks.

Greek astronomer Ptolemy cataloged this horned constellation more than 2000 years ago and Taurus is often associated with the Greek myth of Europa and the Bull. Zeus fell in love with Europa, daughter of King Agenor, and transformed himself into a magnificent white bull. Europa noticed him when she and her handmaidens went to the seashore to gather flowers.

The bull was so docile that Europa climbed onto its back, when, to her surprise, it jumped into the sea and carried her to Crete. Zeus and Europa had three sons and the oldest was Minos, King of Crete.

King Minos is known for building the palace at Knossos and sacrificing seven young men and seven young women to the Minotaur each year.

To help you spot Taurus, here’s how SkySafari 6 shows it.

Taurus the bull shown as an image overlaying the constellation
Taurus the bull, shown over the constellation

Taurus has an area of 797 square degrees making it the 17th largest of the 88 recognized constellations. Taurus is known for being home to the Pleiades (or Seven Sisters) and for its bright stars Aldebaran, Elnath, and Alcyone.

If you’ve observed the annual Taurid meteor shower, which peaks ~Nov 11, you may recognize this constellation as the location of the radiant.

The whole constellation is larger than just the shape of the familiar horns. If you click on the image below, you’ll see that the area occupied by Taurus borders (from the top, clockwise) Orion, Eridanus, Cetus, Aries, Perseus, Auriga, and Gemini.

IAU boundaries for the constellation of Taurus
IAU boundaries of Taurus. Click for full-screen

In the next section discover how to find Taurus.

How To Find Taurus In The Night Sky

Taurus is part of the zodiac family of constellations and is visible to observers at latitudes between +90° and -65°. Zodiac constellations are ones that the Sun travels through over the course of the year, i.e. they are the backdrop to the ecliptic.

Northern Hemisphere observers can see Taurus best in the evenings of fall and winter, while Southern Hemisphere observers can see it during late spring and summer. The image below shows its position on New Year’s Day at 8pm.

Taurus position in the sky on winter evenings
Taurus high over the southeast on New Year’s Day (click for full-screen)

To find Taurus, do a naked-eye search for the bright star Aldebaran. Alternatively, carry out a naked-eye search for Orion’s Belt. The three stars in this asterism are Mintaka, Alnilam, and Alnitak.

Draw an imaginary line from Alnitak to Mintaka (~3°) then extend this line ~20° to Aldebaran (use these hand measurements to estimate distance in degrees).

The stars of Orion’s belt point towards Aldebaran. Click for full-screen

To find Taurus’s exact position for your location on any night, use software such as Stellarium (free) or SkySafari 6, which produced the star maps on this page.

Taurus’s Brightest Stars

Taurus contains several notable stars. See them on the image below, which can be clicked for a full-screen version, with more detail on each underneath that.

Stars brighter than magnitude 5.0 in Taurus. Click for full-screen

Alpha Tauri (Aldebaran) – This variable double star has a combined magnitude of 0.87 making it the brightest star in Taurus and the thirteenth brightest star in the night sky.

The 0.99 magnitude orange giant primary and 13.60 magnitude red dwarf secondary components are 31.6 arcseconds apart. The star is 65 light-years away and close enough to the ecliptic to be occulted by the Moon.

Aldebaran marks the red eye of the bull and its name means ‘follower’ in Arabic.

Aldebaran, Rigel (in Orion), Sirius (Canis Major), Procyon (Canis Minor), Capella (Auriga), and Castor and Pollux (both in Gemini) form an asterism known as the Winter Hexagon.

The winter hexagon made of the stars Aldebaran, Rigel, Sirius, Procyon, Pollux, Castro, and Capella
The Winter Hexagon. Click for full-screen

Beta Tauri (Elnath, Alnath) – This double star is the second-brightest star in Taurus and the twenty-fifth brightest star in the night sky. This used to be a star that linked constellations, for it also had a catalog designation (now unused) for the constellation of Auriga.

The 1.67 magnitude blue giant and secondary components are 33.4 arcseconds apart. Elnath marks the tip of Taurus’s northern horn and is 130 light-years away. Elnath means ‘the butting one’ in Arabic.

Gamma Tauri (Hyadum I) – This double star is located at the base of the ‘V’ marking the start of Taurus’s head. This is a magnitude 3.65 yellow-orange giant whose primary and secondary components are 0.4 arcseconds apart. This star system is 151 light-years away.

Delta1 Tauri (Hyadum II) – This magnitude 3.75 star is a triplet system 153 light-years away within the Hyades cluster, which we’ve more information on below.

The yellow-orange giant primary and 13.21 magnitude dwarf secondary components are 112 arcseconds apart. The third component is another dim dwarf star.

This star can be occulted by the Moon and occasionally is occulted by a planet.

Delta2 Tauri – This double star is within the Hyades cluster. The secondary is too faint to see in an average backyard scope, shining at magnitude 14.7 146 arcseconds from the primary.

The primary star is a hot white main-sequence star shining at magnitude 4.80 and is 161 light-years away. This star can also be occulted by the Moon and occasionally by a planet.

Delta3 Tauri – This double star is also within the Hyades cluster.

The 4.30 magnitude white subgiant primary and magnitude 7.85 secondary components are 1.8 arcseconds apart. The secondary component has an unknown orbit.

Delta3 Tauri is 149 light-years away and is also close enough to the ecliptic to be occulted by the Moon and, occasionally, by a planet.

Epsilon Tauri (Ain, Oculus Borealis) – This double star marks Taurus’s northern eye. The primary and secondary stars are 190 arcseconds apart.

The primary is a 3.53 magnitude orange giant, while the secondary shines at magnitude 10.60 magnitude. The star system is 155 light-years away.

Ain means ‘the bull’s eye’ in Arabic and Oculus Borealis means ‘northern eye’ in Greek. This star can be occulted by the Moon.

Zeta Tauri – This variable, double star marks the tip of Taurus’s southern horn and is 420 light-years away from us. The two components are too close to be separated in a backyard telescope. The primary varies from magnitude 2.88 to 3.17 over 133 days.

Eta Tauri (Alcyone) – This variable double star is the third-brightest star in Taurus and the brightest star in the Pleiades star cluster. It is 430 light-years away from us.

The primary and secondary stars are 118 arcseconds apart from each other. The primary is a magnitude 2.86 magnitude blue-white giant star, while the secondary shines at magnitude 6.27.

The primary component (Alcyone A) is an eclipsing binary consisting of two giant stars. The secondary component is actually three separate stars: white, main-sequence Alcyone B, white, main-sequence Alcyone C, and yellow, main-sequence Alcyone D.

Theta1 Tauri – This variable double star is 154 light-years away. The 3.83 magnitude yellow-orange giant primary and 11.96 magnitude main-sequence secondary components are 268.3 arcseconds apart.

Theta1 Tauri is part of the Hyades cluster.

Theta2 Tauri – This variable double star is 150 light-years away. The magnitude 3.41 yellow-white giant primary and its magnitude 3.94 main-sequence secondary component are 347.9 arcseconds apart.

Theta2 Tauri is part of the Hyades cluster.

Iota Tauri – This double star is 173 light-years away. The 4.61 magnitude white main-sequence primary and 5.4 magnitude secondary component are 0.1 arcseconds apart and so can’t be separated in a backyard telescope.

Kappa1 Tauri – This double star is 154 light-years away. The 4.21 magnitude, white, subgiant, primary and 5.29 magnitude secondary components are 339.4 arcseconds apart.

Lambda Tauri (Elthor, Althor) – This triple stars system is 480 light-years away. The 3.42 magnitude blue-white main-sequence primary shares a common center of gravity with its white, subgiant companion. The pair form an eclipsing binary. The third component remains unconfirmed.

The names Elthor and Althor are both derived from the Arabic for ‘The Bull of the Pleiades’.

Mu Tauri – This is a blue-white subgiant star shining at magnitude 4.28 and it is 456 light-years away. It is 4.1 times the Sun’s diameter, 7.0 times the Sun’s mass, and 3.3 times hotter than the Sun.

Nu Tauri – This double star is 117 light-years away. The 3.90 magnitude white main-sequence primary and its secondary component are 16.1 arcseconds apart. The orbital period of the secondary is unknown.

Xi Tauri – This double star is 209 light-years away. It is comprised of a magnitude 3.73 blue-white main-sequence primary and a magnitude 7.55 secondary which are 0.5 arcseconds apart.

Omicron Tauri – This 3.6 magnitude yellow-orange star is an eruptive variable with an unknown period. Omicron Tauri is 291 light-years away.

Pi Tauri – This magnitude 4.69 yellow-orange giant star is 417 light-years away.

Rho Tauri – This is a yellow-white main-sequence star shining at magnitude 4.65, and is 158 light-years away from us.

Sigma2 Tauri – This double star is 156 light-years away. The magnitude 4.67 white main-sequence primary and magnitude 5.09 secondary component are 444.0 arcseconds apart.

Tau Tauri – This double star is 398 light-years away. The 4.26 magnitude blue-white main-sequence primary and 7.02 magnitude secondary component are 62.5 arcseconds apart.

Upsilon Tauri – This double star is 154 light-years away. The 4.28 magnitude yellow-white main-sequence primary and 13.15 magnitude secondary components are 116.0 arcseconds apart.

Phi Tauri – This double star is 321 light-years away. The magnitude 4.94 orange giant primary and magnitude 7.51 secondary components are 48.7 arcseconds apart.

Omega2 Tauri – This double star is 94 light-years away from Earth. The 4.92 magnitude yellow-white primary and magnitude 9.63 secondary components are 179.3 arcseconds apart.

17 Tauri (Electra) – This variable double star is the third-brightest star in the Pleiades star cluster and is 400 light-years away. The 3.71 magnitude blue-white giant primary is 99 arcseconds from its magnitude 13.00 secondary companion.

19 Tauri (Taygeta) – This double star is the sixth-brightest star in the Pleiades star cluster and is 410 light-years away. It consists of a magnitude 4.30 magnitude blue-white subgiant primary and a magnitude 10.99 secondary which are 71.7 arcseconds apart.

Occasionally this star is occulted by the Moon.

20 Tauri (Maia) – This star is the fourth-brightest star in the Pleiades star cluster and is 385 light-years away. The 3.88 magnitude blue-white giant primary and 13.72 magnitude secondary components are 113.4 arcseconds apart.

23 Tauri (Merope) – This double star is the fifth-brightest star in the Pleiades star cluster and is 380 light-years away. The 4.17 magnitude blue-white subgiant primary and its magnitude 14.42 secondary component are 110.6 arcseconds apart.

27 Tauri (Atlas) – This double star is the second-brightest star in the Pleiades star cluster and is 425 light-years away. The magnitude 3.63 blue-white giant primary and the magnitude 13.23 secondary components are 95.1 arcseconds apart.

28 Tauri (Pleione) – This variable double star is the seventh-brightest star in the Pleiades star cluster and is 380 light-years away. The 5.05 magnitude blue-white main-sequence primary and its magnitude 12.00 secondary component are 168.1 arcseconds apart.

Star Hopping From Taurus

Taurus is the starting point for two well-known star hops.

M1, The Crab Nebula – Begin at Aldebaran and move east along Taurus’s southern ‘horn’ to the star at its end, Zeta Tauri. From here, hop ~1° northeast to the first object in the Messier catalog.

Hyades Cluster (Cauldwell 41) – Begin at Aldebaran and move westwards to the star Hyadum I, which marks the point where the two horns of Taurus meet. The Hyades Cluster is the ‘V’ shape around Aldebaran.

Objects To See Within Taurus

Taurus contains two Messier objects and some other deep sky objects for small telescopes.

M1 (NGC 1952, Crab Nebula) – This bright nebula has a magnitude of 8.39 and an apparent size of 6.0 x 4.0 arcminutes. It is 1,350 light-years away and can be found at right ascension 05h 34m 30s and declination +22° 01’ 00” (J2000.0). In the year 1054, Chinese astronomers noted the stellar explosion that resulted in this nebula.

M45 (Pleiades, Seven Sisters, Subaru Cluster) – This open cluster has a magnitude of 1.50 and an apparent size of 120 arcminutes. It’s 430 light-years away and is at right ascension 03h 47m 00s and declination +24° 07’ 00”.

Hyades (Caldwell 41, Melotte 25) – This open cluster has a magnitude of 0.50 and an apparent size of 330.0 arcminutes. The cluster is 147 light-years away and is located at right ascension 04h 26 54s and declination +15° 52’ 00”. This cluster of several hundred stars forms a distinctive ‘V’ that marks the head of Taurus.

NGC 1435 (Merope Nebula, Temple’s Nebula) – This bright nebula has a magnitude of 4.19 and an apparent size of 30.0 x 30.0 arcminutes. It is 359 light-years away at right ascension 03h 46m 06s and declination +23° 47’ 00”.

NGC 1514 (Crystal Ball Nebula) – This planetary nebula has a magnitude of 10.89 and an apparent size of 2.3 x 2.0 arcminutes. It’s 2200 light-years away, located at right ascension 04h 09m 17s and declination +30° 46’ 35”.

NGC 1555 (Hind’s Variable Nebula) – This bright nebula has a magnitude of 10.00 and an apparent size of 4.0 x 3.0 arcminutes. It’s 550 light-years away and is at right ascension 04h 22m 00s and declination +19° 32’ 00”.

NGC 1647 – This open cluster has a magnitude of 6.40 and an apparent size of 40.0 arcminutes. It’s 1,800 light-years away and is at right ascension 04h 45m 55s and declination +19° 06’ 00”.

NGC 1746 – This open cluster has a magnitude of 6.09 and an apparent size of 42.0 arcminutes. It’s 2,600 light-years away and is at right ascension 05h 03m 50s and declination +23° 46’ 00”.

NGC 1807 – This asterism looks like an open cluster with a magnitude of 7.00 and an apparent size of 15.0 arcminutes. It’s at right ascension 05h 10m 43s and declination +16° 31’ 00”.

NGC 1817 – This open cluster has a magnitude of 7.69 and an apparent size of 16.0 arcminutes. It’s 6,400 light-years away and can be seen at right ascension 05h 12m 15s and declination +16° 41’ 00”.

Summary

Taurus is a large constellation with many notable stars and deep sky objects. It’s the starting point for two easy star hops. Hop over to it from Orion and enjoy this constellation’s wonders.


Written by Tanya C. Forde