Cetus is one of the 48 ancient constellations recorded by Ptolemy, and one of several constellations linked by a single mythology. Cetus represents a sea-monster sent to ravage the coast of Ethiopia (a much larger kingdom at that time than the current country), as a result of Cassiopeia
, Queen of Ethiopia, angering the sea-god Poseidon by declaring herself more beautiful than any of the Nereids. (See Andromeda
for the rest of the story.) Note that although now usually called The Whale (whales being cetaceans), traditional pictures show the constellation not as a whale, but as a true monster of the sea.
Historical Maps of Cetus
From Bayer's 1603 Uranometria (Image Credit and © Tartu Observatory Virtual Museum; used by permission)
The horizontal bands at the top represent the Ecliptic (with degree markings) and the southern half of the Zodiac
From Bode's 1801 Uranographia (Image Credit and © Tartu Observatory Virtual Museum; used by permission)
Although labeled Cetus on the left, it is also labeled "Monstrum Marinum" (Sea Monster) on the right
Unlike Bayer's maps, which only show naked-eye stars (the telescope not having been invented), Bode's maps show many fainter stars. In addition, several constellations are shown to the south of the sea monster that did not exist at the time of Bayer's work -- Apparatus Chemicus (an alteration of Nicolas-Louis de Lacaille
's Le Fourneau, now called Fornax
), Machina Electrica
(now obsolete), and Apparatus Sculptoris (now Sculptor
Modern Map of Cetus
Wikimedia Commons map by IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
Constellations Bordering Cetus
(to be added in the next iteration of this page)
Stars in Cetus
Stars that have common names often have multiple names, so the common names shown (if any) cannot be considered authoritative. Right ascension and declination are given in 2000.0 coordinates.
β Cet (Deneb Kaitos = Diphda) -- In early Arabic times, this star and Fomalhaut (a first-magnitude star to its west) were called the frogs, which is the source of the name Diphda. After Al Sufi translated ancient Greek texts into Arabic, Greek constellations replaced the Arabic ones, and this star, being on the western or "tail" side of the constellation (as shown in Bayer's map), became "the tail of the whale", or Deneb Kaitos. However, since the mid 20th century the constellation has often been drawn with its head to the west and its tail to the east, placing "the tail of the whale" in the whale's mouth. As a result, the old Arabic name of the star has come into use again. Whether this accomplishes anything save confusing those trying to learn the name of the star is another matter, and is the reason Bayer created the designation "Beta Ceti".
Objects of Interest