Cetus

From Freepedia

Cetus
Image:Cetus constellation map.png click for larger image
Abbreviation	Cet
Genitive	Ceti
Symbology	the Whale or Sea Monster
Right ascension	1.42 h
Declination	−11.35°
Area	1231 sq. deg. Ranked 4th
Number of stars (magnitude < 3)	3
Brightest star	β Cet (Deneb Kaitos)† (App. magnitude 2.04)
Meteor showers	October Cetids Eta Cetids Omicron Cetids
Bordering constellations	Aries Pisces Aquarius Sculptor Fornax Eridanus Taurus
Visible at latitudes between +70° and −90° Best visible at 21:00 (9 p.m.) during the month of November
Note: †Mira (ο Cet) is magnitude 2.0 at its brightest.

Cetus (a name from Greek mythology, referring to a Whale or Sea monster, see Ceto) is a constellation of the southern sky, in the region known as the Water, near other watery constellations like Aquarius, Pisces, and Eridanus.

1 Notable features
2 Notable deep sky objects
3 History and Mythology
4 Stars
5 External links

Notable features

This constellation's most notable star is Mira (ο Ceti), the first variable star to be discovered. Over a period of 331.65 days it can reach a maximum magnitude as high as magnitude 2.0, one of the brightest in the sky and easily visible to the unaided eye, to 10.1 and back again. Its discovery in 1596 by David Fabricius further dented the supposed unchangeability of the heavens and lent support to the Copernican revolution.

Other stars in the constellation include α Ceti (Menkar); β Ceti (Deneb Kaitos), brightest in the constellation; and τ Ceti, the 17th closest star to Earth.

The ecliptic passes close to the constellation boundary of Cetus, and thus planets may be in this constellation for brief periods of time. This is even more true of asteroids, whose orbits usually have a greater inclination to the ecliptic than planets. The asteroid 4 Vesta was discovered in this constellation in 1807.

Notable deep sky objects

Cetus lies far from the galactic plane, so many distant galaxies are visible, unobscured by dust from the Milky Way. Of these, the brightest is M77, a 9th-magnitude spiral galaxy near δ Ceti.

History and Mythology

This constellation has been known since antiquity. In Mesopotamia, it was identified with the primordial cosmic female principle, the sea-monster Tiamat.

In Greek mythology, together with the constellations above it, of Andromeda, Cepheus, Perseus, Cassiopeia, and possibly Pegasus), this may be the source of the myth of the Boast of Cassiopeia, with which it is usually identified.

In certain earlier Greek mythology, it also represented the gates (and gateposts) of the underworld (considered to be the area under the ecliptic). As such, together with other features in the Zodiac sign of Pisces (including Pisces itself, as well as prominent stars behind Cetus), it may have formed the basis of the myth of the capture of Cerberus in The Twelve Labours of Herakles.

Stars

Stars with proper names:

(92/α Cet) 2.54 Menkar or Menkab [Mekab] or Monkar
< منخر minxar nostril
< منكب minkab shoulder
< (?) منقار minqār peak (snout)

(16/β Cet) 2.04 Diphda [Difda al Thani] or Deneb Kaitos or Rana Secunda
< الضفدع الثاني ađ̧-đ̧ifda^{c^aθ-θānī} The second frog
< ذنب ðanab Tail [of Cetus]