Perseus (constellation)

Perseus
Abbreviation	Per
Genitive	Persei
Meaning in English	Perseus
Right ascension	3 h
Declination	+45°
Visible to latitude	Between +90° and -35°
On meridian	December
Area  - Total	Ranked 24th 615 sq. deg.
Number of stars with apparent magnitude < 3	5
Brightest star  - Apparent magnitude	Mirphak (α Persei) 1,79
Meteor showers	Perseids September Perseids
Bordering constellations	Cassiopeia Andromeda Triangulum Aries Taurus Auriga Camelopardalis

Perseus is a northern constellation, representing the Greek hero who slew the monster Medusa. It is one of Ptolemy's 48 constellations and was also adopted by the International Astronomical Union as one of the 88 modern constellations. It contains the famous variable star Algol (β Per), and is also the location of the radiant of the annual Perseids meteor shower.

Table of contents

1 Notable features 2 Notable deep sky objects 3 Mythology 4 External Links

Notable features

Here are some of its stars:

• Mirphak (α Per): The brightest star of this constellation is also called Algenib (a name which is used for other stars as well, e. g. γ Peg). Mirphak (Arabic for elbow) is a supergiant of spectral type F5 Ib with an apparent brightness of 1.79m lying at a distance of ca. 590 light-years. Its luminosity is 5,000 times and its diameter is 62 times that of our Sun.
• Algol (β per): This may not be the brightest star of this constellation, but it definitely is its most famous star. Algol (from Arabic al-Ghul, which means The Ghoul or The Demon Star) represents the eye of the gorgon Medusa. This star is the prototype of a whole group of eclipsing variable stars. Its apparent brightness ranges between 2.12m and 3.39, and this within a period of merely 2.867 days. It is of spectral type B8 V and lies at a distance of only 93 ly.

Notable deep sky objects

• h+χ Per: These two open clusters (NGC 869 and NGC 884 respectively) belong to the most beautiful objects of the night sky for binoculars and small telescopes. Both lie at distances of more than 7,000 ly and are separated by several hundred light-years.
• M 34: This open cluster with an apparent brightness of 5.5m lies at a distance of approximately 1,400 ly and consists of about 100 stars that are scattered over an area larger than that of the full moon. Its true diameter is about 14 ly. M 34 can be resolved even with good binoculars but is best viewed using a telescope at low magnifications.
• M 76: This planetary nebula is also called Little Dumbbell Nebula. It measures about 65 arc seconds and has an apparent brightness of 10.1m.
• NGC 1499: Also called California Nebula this emission nebula, discovered in 1884-85 by the American astronomer Edward E. Barnard, is a great target for astrophotographers. Due to its low surface brightness it's a very difficult object when observed visually.

Mythology

Perseus is the protagonist of one of the most famous of the ancient Greeks' many interesting myths. This story also concerns several other constellations, namely Cassiopeia, Cepheus and Andromeda.

Perseus was the son of mortal Danae and the god Zeus. He went on a quest to obtain the head of the gorgon Medusa as a wedding present for Dictys, the brother of king Polydectes of Seriphos (the quest was actually only a ruse on Dictys' side). With a bit of help of the gods Hermes and Athena he finally managed to kill the gorgon and take her head. On the way back he rescued Andromeda (daughter of Cepheus and Cassiopeia, king and queen of Ethiopia) from a sea-monster. For more details on this myth see Perseus (mythology).

External Links

• SEDS' comprehensive Messier Catalog