II. sign of zodiac
Particulars:
General:
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.
Mythological Background:
The great hunter Orion is permanently fighting the bull.