Coma Berenices, or Berenice's Hair, is a constellation in the northern hemisphere. It used to be an asterism in the constellation Leo before it was defined as one of the 88 constellations.
The name Coma Berenices refers to the story of Queen Berenice II of Egypt, wife of Ptolemy III Euergetes, who swore to the goddess Aphrodite that she would cut her long, blond hair if her husband returned home safely from a dangerous expedition. Once he did, she made good on her word and placed her hair in Aphrodite's temple. The next morning, the hair was gone. The king and queen were furious until their astronomer informed them that Aphrodite was so pleased with Berenice's hair that she placed it in the sky. He pointed to a cluster of stars which have since been called Berenice's Hair.
The Greek astronomer Ptolemy considered the asterism as part of the constellation Leo
and did not include it among his 48 constellations. It was the 16th century Danish nobleman and astronomer Tycho Brahe who promoted Coma Berenices to constellation status in his star catalogue of 1602.
Coma Berenices occupies an area of 386 square degrees and contains two stars with known planets. It can be seen at latitudes between +90° and -70° and is best visible at 9 p.m. during the month of May. The North Galactic Pole is located in Coma Berenices, at right ascension 12h51m25s and declination +27°07'48".
The brightest star in Coma Berenices is 
beta Comae Berenices, with an apparent visual magnitude of 4.26. It is a main sequence dwarf only slightly brighter than the Sun. The star serves as an indicator of what our Sun would look like when observed from that distance.
alpha Comae Berenices is the second brightest star. It is also known as Diadem, referring to Berenice’s crown. It is a binary star system with two almost equal components orbiting each other. The system is approximately 65 light-years away from Earth.
Coma Berenices contains as many as eight Messier objects and a number of notable galaxies despite not being a very large constellation. The Coma Berenices Open Cluster, or Melotte 111, is a large cluster of about 40 stars, covering an area of more than five degrees across, with magnitudes between 5 and 10, some of which can be seen with the naked eye. The brighter stars in the cluster form a ‘V’ shape. The cluster is only about 270 light-years distant.
NGC 5024, or Messier 53, is one of the outlying globular clusters, approximately 58,000 light-years away, that can be spotted with binoculars. It has a round shape and a very bright centre. The stars in the cluster are metal-poor, with little quantities of elements heavier than helium.
Another globular cluster that lies only a degree away is NGC 5053, a cluster with fewer stars, spread much more loosely, and a nucleus that is not quite as concentrated as the one in NGC 5024. The stars in the cluster are old and also lacking in heavy elements.
NGC 4147 is a much smaller and dimmer globular cluster, with a magnitude of 10.2. Depending on the telescope, it can appear as a faint, diffuse round cluster with a slightly discernible centre or as a bright, round cluster without a discernibly brighter core.
NGC 4826, or Messier 64, is much better known as the Black Eye Galaxy because it has a notable black dust band lying in front of the bright nucleus. It is a spiral galaxy lying only 17 million light-years away from Earth. It is also sometimes called the Sleeping Beauty or Evil Eye Galaxy. The Black Eye Galaxy can be seen in small telescopes. What is particularly interesting about it is that the interstellar gas in the outer area rotates in the opposite direction from the stars and gas in the inner area, which is believed to cause the creation of a multitude of new stars in the region separating the inner and outer area of the galaxy.
NGC 4565, also known as the Needle Galaxy, is an unbarred spiral galaxy approximately 20 million light-years distant. It is one of the most famous examples of a spiral galaxy seen edge-on. The Needle Galaxy has a magnitude of 10 and is located almost exactly above the North Galactic Pole. It can be seen in a small telescope.
Coma Berenices is also home to the northern part of the Virgo Cluster of galaxies. Spiral galaxy NGC 4321, or Messier 100, lies about 52.5 million light-years away and can be seen face-on. Five supernovae have been identified in it. It has over 100 billion stars and is among the brightest galaxies in the Virgo cluster. NGC 4321 is also sometimes identified as a grand design galaxy, with notable and well-defined spiral arms. The core contains bright blue star clusters and winding streams of dust. NGC 4321 also has a satellite galaxy, NGC 4323.
NGC 4382, or Messier 85, is a lenticular galaxy lying at the northernmost edge of the Virgo Cluster. It is also among the brightest galaxies in the area and, lying 60 million light-years away, one of the most distant Messier objects.
NGC 4192, or Messier 98, is a bright, elongated intermediate spiral galaxy with a small nucleus and huge spiral arms. It can be seen edge-on, as a diffuse disk with some blue areas marking regions of newly formed stars, and a lot of dust dimming the light of the nucleus. The galaxy is approximately 60 million light-years distant and approaching us at 125 kilometres per second.
NGC 4254, or Messier 99, lies about a degree and a half away from NGC 4192, and is another bright galaxy in the cluster. It is an unbarred spiral galaxy about 60 million light-years distant. Sometimes it is referred to as the "Pinwheel Nebula," a name more commonly associated with the Triangulum Galaxy. Three supernovae have been recorded in the galaxy in the last 50 years.
NGC 4501, or Messier 88, is another spiral galaxy with multiple arms, about 47 million light-years distant. It is quite bright and symmetrical, in the shape of an elongated ellipse. It is moving away from us at about 2,000 km/sec and can be easily seen in smaller telescopes.
NGC 4548, or Messier 91, is a barred spiral galaxy, approximately 63 million light-years distant. Being the faintest of Messier objects, the galaxy is very difficult to spot with a regular telescope.
The Coma cluster of galaxies contains about a thousand large galaxies and up to 30,000 smaller ones, but most of them can only be seen in large telescopes. The brightest galaxies in the cluster, supergiant elliptical galaxies NGC 4889 and NGC 4874, are both of thirteenth magnitude. The brightest spiral galaxy in the Coma cluster is NGC 4921, located near the center of the cluster and about 320 million light-years distant.
Coma Berenices belongs to the Ursa Major family of constellations, along with Ursa Major
, Ursa Minor
, Canes Venatici
, Corona Borealis
, Leo Minor
Constellations directly bordering Coma Berenices are Canes Venatici
, Ursa Major