Pisces

Pic.

Abbreviation:

Psc

English name:

Fishes

Coordinates

see Stellar data. Coordonnées Céleste

XII. sign of zodiac

Particulars:

• Variable stars TX Psc, TV Psc, UU Psc
• Double stars alpha Psc, zeta Psc, rho Psc, psi1 Psc, 7 Psc
• Spiral galaxy M74
• Meteor Showers: Piscids, May Piscids, Gamma Piscids
  Mythologie: Pisces

General:

A faint constellation of the equatorial region of the sky. Just north of Aquarius and Cetus it is surrounded by Pegasus, Andromeda, Triangulum and Aries. The boundaries are streching from DECL=-5 degrees to DECL=+34 degrees and RA=22h 50m to RA=2h 10m.
The sun passes through Pisces from mid-March to late April (so it is best viewed in autumn). Around March 21th each year the sun crosses on its way from the south to the north the celestial equator. This point is called vernal equinox and lies within Pisces (DECL=0 degrees, RA=0h).
Directly south of the Great Square of Pegasus lies a faint, yet distinctive group of stars: gamma Psc, theta Psc, iota Psc, lambda Psc and kappa Psc. They form an irregular pentagon, known as the asterism Circlet.

Stars and other objects

The variable star TX Psc (19 Psc) shows a deep red color (spectral type C5III). The brightness of this red giant varies irregularly between 5th and 6th mag.
The binary alpha Psc (a 1615), called Al Rischa (meaning: the cord) is a close double of two A stars (of 5.23 mag and 4.33 mag). To split this pair in a telescope it should have at least 100 mm aperture.
An easier pair to split is zeta Psc. The A7 subgiant of 5.24 mag and its F7 main sequence companion of 6.3 mag are readily resolved in small scopes.
The F2 main sequence star rho Psc forms with 94 Psc a quite attractive binocular white-orange pair.
The double psi1 Psc consists of two blue-white stars of 5 mag brightness. It is a wide pair which can be observed with small scopes.
The binary 7 Psc (a 16665) requires scopes with an aperture of at least 125mm to be resolved. The two stars of 9th and 10th magnitude revolve each other every 85.7 years.
The galaxy M74 is a prototype of a Sc spiral. To see more than the bright core very good observing conditions are necessary. Under such circumstances a scope with an aperture of about 100mm reveals a bit of the spiral arms.
From August, 12th, to October, 7th, the weak and diffuse meteors shower Piscids takes place. The maximum with five meteors per hour is reached on September, 11th.
The Gamma Piscids have been discovered by Zdenek Sekanina. The duration of this meteor shower is not very well determined but it seems to take place from about end of August to mid-October.

Mythological Background:

When Venus and Cupido had to fly from Typhon in Egypt the were changed into two fishes in the sky (see C. Julius Hygenius "Poeticum astronomicum", l.II.c.30).