PERSEUS, The Greek hero, pronounced PURR-syoos or PURR-see-us.

Chart showing the constellation.

Perseus was the mythological Greek hero who rescued the chained princess Andromeda from the clutches of the sea monster, Cetus. Perseus had previously slain Medusa the Gorgon, and he is pictured holding her head in one hand. The winking star, Algol or β Persei represents the Gorgon's evil eye.

The Perseid meteor shower is one of the most glorious in the northern sky. Around August 12th to 13th as many as 60 bright meteors an hour can be seen streaming from Perseus. The point where they appear to originate, the radiant, is near γ Persei.

The famous California nebula (NGC 1499) is a very large faint nebula near ξ Persei.

Perseus is rather low in the northern sky, and not all the constellation is visible from New Zealand. The horizon is for Auckland; residents of Christchurch would see from the constellation name up.

To find Perseus look very low to the north late in the evening, below the famous open cluster "The Pleiades" or "Seven Sisters".

Chart of the constellation as seen to the north at about 11.00 pm NZDT in mid December.

Perseus chart

Constellation Orion Constellation Auriga Constellation Triangulum Constellation Aries Constellation Cetus Constellation Andromeda Constellation Pisces Constellation Taurus

Some stars and interesting objects in the Constellation

α Persei (Mirfak, the elbow, or Algenib, the side) is a magnitude 1.8 yellow supergiant star 592 light years away.

β Per (Algol, the demon) is one of the most celebrated variable stars in the sky. It is an eclipsing binary star whose variation was first noted by Geminiano Montanari in 1667. The system is two close stars periodically eclipsing each other every 2.867 days as they orbit their common centre of gravity. The star's apparent brightness lowers from magnitude 2.2 to 3.5 for a period of 10 hours, before returning to maximum. John Goodricke in 1782, first suggested the variable behaviour was due to it being two stars and this was confirmed spectroscopically in 1889.

It is known now that this is a triple system of a cool 0.81 solar mass giant star with a very close 3.7 solar mass main sequence star orbiting every 2.867 days. The third star orbits with a period of 1.8 years. Distance is about 93 light years.

γ Per is a magnitude 2.9 yellow giant star 256 light years away.

δ Per is a magnitude 3.0 blue giant star 528 light years away.

ε Per is a magnitude 2.9 blue-white star with a magnitude 8.1 companion star. The magnitude difference makes this difficult to see in small telescopes. The system lies 538 light years away.

ζ Per is a magnitude 2.9 supergiant with a magnitude 9.4 companion, 982 light years away.

M 34 is a bright star cluster resolvable into stars with good binoculars. It is a fine scattered group needing a large field to be seen well.

Visibility

Only the southern parts of the constellation are visible from New Zealand and are above the horizon for only a few hours at the most. Some of the constellation remains briefly visible after the end of evening twilight until early March.

α has a maximum altitude of just over 3° from Auckland, and so is virtually unobservable further south. Algol, β Per, is visible from all New Zealand, but has a maximum altitude of less than 3° from Invercargill.