Pisces (constellation)
Piscids
- Andromeda
- Pegasus
- Aquarius
- Whale
- Aries
- Triangle
The fish ( Pisces latin astronomical sign: ♓ ) is a constellation on the ecliptic.
Description
The fish lie on the ecliptic, so pull the sun, moon and the planets through the constellation. The sun is believed to be currently from March 12 to April 19 of each year, in the constellation Pisces on.
The ecliptic crosses the celestial equator in the fish. This intersection point of the vernal equinox, is the origin of the most important astronomical coordinate systems at the starry sky. The time at which the Sun crosses the celestial equator corresponds to the astronomical beginning of spring in the northern hemisphere. In the year 2597 this point, today's constellation boundaries is assumed to migrate into the constellation Aquarius.
History
The fish are among the 48 constellations of the ancient Greek astronomy, which have already been described by Ptolemy. The constellation was named for the zodiac sign Pisces astrology. However, the passage of the sun has changed due to the precession of Earth's axis relative to the antiquity.
In the year 7 BC it came into the fish to a rare triple conjunction between Jupiter and Saturn ( Largest conjunction). That is, the two planets met three times over the course of a year. Conjunctions between Jupiter and Saturn occurred while approximately every 20 years, but few are with such a small angular distance that both look the same triple almost like a single star. This is only every 854 years to see and consequently presented for Babylonian astronomers a millennium event dar. that time were the planets Jupiter Saturn and Venus with Mars all in a row in the constellation Pisces ( fish) are observed later. These two facts gave rise to hypotheses that those Jupiter - Saturn conjunction as the star of Bethlehem in the history of Christian faith and the world entered. So fish pictures were in ancient times also a secret character recognition among Christians. To date, however, the actual situation is unclear, even purely symbolic interpretations or comets have been proposed as the basis of the Three Kingdoms story.
Mythology
The Babylonians took the constellation with the love goddess Ishtar in conjunction.
The ancient Greeks adopted this interpretation obvious later. In their mythology, the fish represent the love goddess Aphrodite and her son Eros, who jumped on the run from the monster Typhon into the Euphrates, were transformed into fish and escaped.
The Romans have the fish often than Imbrifer Duo Pisces, referred to as the two rain -bearing fish, or even as Gemini Pisces and Piscis Gemellus, ie as a pair of fish.
Celestial objects
Stars
The brightest star of the fish is η Piscium, also called Kullat Nunu. He is a 294 light-years distant, luminous yellow giant star with four times the mass, diameter 25 times and 300 times the luminosity of our Sun.
β Piscium is a 493 light-years distant, bluish star of spectral type B6 V. The name Fum al Samakah is of Arabic origin and means something like " mouth of the fish ".
Double stars
Variable Stars
47 Piscium is a 400 light- years away in semi- regular variables that changes brightness over a period of about 50 to 85 days. He is a reddish star of spectral type M3 III.
19 Piscium is a red giant of spectral type C5 II in 2000 light years away. He has the 700fachen diameter of our Sun and is one of the largest known stars. Its brightness changes with no discernible regularity.
Messier and NGC objects
In the fish three galaxies are visible. One took the French astronomer and comet hunter Charles Messier in his catalog of nebulous objects ( Messier catalog).
M 74 is a galaxy about 30 million light -years away. They are found west of the bright star η Piscium. It is not easy to observe, and appears in the prism binoculars under good visibility conditions as very diffuse spots foggy. Spiral structures are visible only in large telescopes.