II. sign of zodiac
The second sign of the zodiac. The sun passes through this constellation from
mid-May to late June; therefore ist best observed in the early wintertime. The
red star alpha Tau, called Aldebaran, represents the
glowing eye of the bull and white star beta Tau, called El
Nath is thought to be the pushing horn. The open cluster of the
Hyades forms the head.
The Bull lies between DECL=+30 and DECL=+10, RA=6h and RA=3h30m.
Stars and objects
The leading star of this constellation, alpha Tau, called
Aldebaran (arab.: the Follower (i.e. of the Pleiades)) is the 13th
brightest star in the sky. It is a red (spectraltype K5III) giant of 0.85 mag.
It lies in a distance of about 68 lightyears.
An interesting object ist the eclipsing binary lambda tau: within 4 days the brightness varies from 3.4 mag to 4.1 mag.
The pair theta1 Tau and theta2 Tau is a wide double in the Hyades (see below). The two stars are divisible by binoculars or even the naked eye (under good observing conditions). The one component is an A7 giant (glowing white) of 3.4 mag and the second a K0 (showing a red color) giant of 3.84 mag.
The 4th mag star kappa Tau forms a wide binocular double with 67 Tau, an A7 main sequence star of 5.28 mag.
Another wide double, which is an good object for binoculars, is sigma1 Tau and sigma2 Tau. Both belong to the luminosity call "A" and show a brightness of 5.07 mag and 4.69 mag, respectively.
Phi Tau is an red giant (spectraltype K1III) of 4.95 mag with an unrelated 9th mag companion. To view them a small telescope is sufficient.
A very attractive pair for small telescopes is chi Tau consisting of an white main sequence star of 5.37 mag and an 8th mag star of golden color.
One of the most famous diffuse nebulae can be found in this constellation: the Crab Nebula, M1. In 1054 A.D. chinese observers recorded the appearance of a "new" star. M1 is the supernova remnant of the star which exploded then. The shape of the nebula reminds of an crab.
The large and scattered open star cluster of the Hyades seems to surround alpha Tau. As a matter of fact the Hyades are much more far away (about 150 lightyears). This cluster has the shape of an V and contains about 200 stars. As it covers 5 degrees of the skies it is best viewed with binoculars.
Most famous in this constellation are certainly the Pleiades (also called "Seven Sisters"), M45. Without optical aid this cluster appears as a dusty group of a few stars (having the advantage of a clear, moonless night far away of all cities six or seven stars can even be seen by the naked eye). In small telescopes this cluster is breathtaking. Detailed information about M1 and M45 can be found in the Messier database.
From October the 12th till December the 2nd the northern branch of the Taurids can be seen. The maximum of the shower activity occurs from November, 4th, to November, 7th. The Southern Taurids are active a bit earlier - from September, 17th, to November, 27th. The maximum of this branch takes place end of October/begin of November. Both showers have an hourly rate of 7.
The Beta Taurids are one of the daylight showers, occuring on June 5th and lasting till July, 18th. They reach an hourly rate of 25 meteors. For detailed information about the Taurids and the Beta Taurids please take a look at the meteor shower database of Gary Kronk.
The great hunter Orion is permanently fighting the bull.