'Cetus' (
IPA: ,
Latinized Greek: ''
whale'') is a
constellation of the southern sky, in the region known as the
Water, near other watery constellations like
Aquarius,
Pisces, and
Eridanus.
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 2.0
m, one of the brightest in the sky and easily visible to the unaided eye, then drop to 10.1
m 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
Ï„ Ceti, the
17th closest star to Earth.
The
ecliptic passes close to the constellation boundary of Cetus, and thus the 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
Messier 77 (NGC 1068), a 9th magnitude
spiral galaxy near
δ Ceti.
History
This constellation has been known since antiquity. In Mesopotamia, it was identified with the primordial cosmic female principle, the sea-monster
Tiamat.
In
Ancient Greece, together with the constellations above it, (
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 legends, 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.
According to the
Arabs, one of the hands of the
Pleiades (''Al-Thurayya'') extended into part of the constellation Cetus. The Arabs also saw two pearl necklaces among the stars of Cetus. One pearl necklace was fully tied together and undamaged, but the other pearl necklace was broken and its pearls were scattered. Another generation of Arabs, like the ancient
Hebrews and Greeks, portrayed an enormous
Leviathan-like sea creature among the stars of Cetus.
References
★ Ian Ridpath and Wil Tirion (2007). ''Collins Stars and Planets Guide'', HarperCollins, London. ISBN 978-0007251209.
External links
★
The Deep Photographic Guide to the Constellations: Cetus
★
Star Tales – Cetus