Cetus or the Whale is a constellation that lies in the region of the sky called the Water, which is home to many other water-related constellations such as Pisces
. Even though Cetus is not considered one of the zodiac constellations, the ecliptic passes very close to its border and some of the planets and asteroids can occasionally be seen in it.
The constellation Cetus represents the sea monster from the Greek myth of Andromeda, the Ethiopian princess sacrificed to a monster to appease the gods, who were angered by her mother Cassiopeia's vanity. Before Cetus was able to swallow Andromeda, she was rescued by Perseus, whom she later married. The constellation Cetus was first charted by the Greek astronomer Ptolemy in the 2nd century.
Cetus occupies an area of 1231 square degrees and contains nine stars with known planets. It can be seen at latitudes between +70° and -90° and is best visible at 9 p.m. during the month of November.
The brightest star in Cetus is 
beta Ceti, also known as Deneb Kaitos ("tail of Cetus") or Diphda ("the second frog"). It is a bright yellowish-orange star 96 light-years away from Earth. It is easy to find because it stands out in a dark patch of the sky.
alpha Ceti is also known as Menkar ("nostril"). It is an old, dying star, currently in its red giant phase. It will soon become unstable, shed its outer layers and form a planetary nebula, leaving a white dwarf remnant.
tau Ceti, only 12 light-years distant from the solar system, is a ‘metal-deficient’ star with a huge debris disk. It is also very similar to the Sun, which makes it one of the top targets for Search for Extra-Terrestrial Intelligence (SETI) studies.
Most of the stars in Cetus are pretty faint, but several of them are pretty well known. UV Ceti, a binary star that consists of a pair of red dwarfs, and 
omicron Ceti or Mira, a red giant binary and a well known variable star, are both located in Cetus.
UV Ceti is a prototype of a class of variable stars known as flare stars. It is a component of a binary pair of red dwarfs known as Luyten 726-8. UV Ceti increases in magnitude about every ten hours – it jumps by three or four magnitudes – and then fades back to its faint self. The star is only 8.4 light-years away. Like all flare stars, it would not be visible to us if it were more than 15 light-years away from Earth. The other component of Luyten 726-8, BL Ceti, is also a red dwarf and a flare star, but not as extreme in behaviour as UV Ceti.
omicron Ceti or Mira was the first variable star to be found in the night sky. It is a red giant approximately 420 light-years distant from Earth. Its maximum magnitude can reach 2.0, making it one of the brightest stars in the sky, and then drop to 10.1 and make the star invisible to the naked eye. When German theologian David Fabricius discovered it in 1596, this put a new dent in the notion of unchangeability of the heavens, undermining the Ptolemaic model and shifting in favour of the Copernican Revolution and the heliocentric model. Mira was named by Polish astronomer Johannes Hevelius. The name means "wonderful" or "astonishing" in Latin. The star is a model for the category of stars known as Mira variables. Mira variables are pulsating variable stars, usually red giants, with pulsation periods longer than 100 days and light amplitudes exceeding one magnitude.
Other notable stars are 
gamma Ceti, a binary star with an interesting colour contrast to observe, yellow and blue, and Struve 186, a close pair of two equal stars.
Cetus also contains a couple of interesting deep sky objects. Messier 77 or NGC 1068 is a magnitude 9 barred spiral galaxy located near 
delta Ceti, 47 million light-years away. It is a Seyfert galaxy, seen face-on.
The galactic cluster JKCS 041 is the most distant group of galaxies ever discovered, approximately 10.2 billion light-years away. It is particularly interesting to astrophysicists because we see it as it appeared when the universe was much younger. Studying it could reveal more about how the universe evolved and took shape.
Cetus falls into the Perseus family of constellations, along with Cassiopeia
Constellations directly bordering Cetus are Aries