A constellation is a specific area of the celestial sphere.
An asterism is a pattern of stars recognized in the Earth's night sky. It may be part of an official constellation or it may be composed of stars from more than one constellation.
There are 88 officially recognized constellations, covering the entire sky.
- The earliest direct evidence for the constellations comes from inscribed stones and clay writing tablets dug up in Mesopotamia dating back to 3000 BC.
- The Babylonians were the first to recognize that astronomical phenomena are periodic and apply mathematics to their predictions.
- Astronomy in the Ancient Egypt was already advanced by 3000 BC, the 365 day period of the Egyptian calendar was already in use, and the observation of stars was important in determining the annual flooding of the Nile.
- The Egyptian pyramids were carefully aligned towards the pole star, and the temple of Amun-Re at Karnak was aligned on the rising of the midwinter sun.
- In ancient China astronomy has had a long tradition in accurately observing celestial phenomena.
- Chinese astronomy dates back to the 1500 BC, and it's at least partially based on Babylonian star charts.
- Indian astronomy also dates back to about 1500BC.
- As with most other ancient civilizations, the use of astronomy was religious.
Alphabetical listing of constellations
Andromeda
Antlia
Apus
Aquarius
Aquila
Ara
Aries
Auriga
Boötes
Caelum
Camelopardalis
Cancer
Canes Venatici
Canis Major
Canis Minor
Capricornus
Carina
Cassiopeia
Centaurus
Cepheus
Cetus
Chamaeleon
Circinus
Columba
Coma Berenices
Corona Austrina
Corona Borealis
Corvus
Crater
Crux
Cygnus
Delphinus
Dorado
Draco
Equuleus
Eridanus
Fornax
Gemini
Grus
Hercules
Horologium
Hydra
Hydrus
Indus
Lacerta
Leo
Leo Minor
Lepus
Libra
Lupus
Lynx
Lyra
Mensa
Microscopium
Monoceros
Musca
Norma
Octans
Ophiuchus
Orion
Pavo
Pegasus
Perseus
Phoenix
Pictor
Pisces
Piscis Austrinus
Puppis
Pyxis
Reticulum
Sagitta
Sagittarius
Scorpius
Sculptor
Scutum
Serpens
Sextans
Taurus
Telescopium
Triangulum
Triangulum Australe
Tucana
Ursa Major
Ursa Minor
Vela
Virgo
Volans
Vulpecula
In both astrology and historical astronomy, the zodiac is a circle of twelve 30° divisions of celestial longitude that are centered upon the apparent path of the Sun across the celestial sphere over the course of the year.
Essentially, the zodiac is a celestial coordinate system.
The term zodiac derives from Latin zōdiacus, which in its turn comes from Greek, meaning "circle of animals".
- Aquarius (the "water-bearer") is the eleventh astrological sign in the Zodiac. It spans the 300-330th degree of the zodiac.
- Aquarius has no particularly bright stars.
- Pisces (the "fish") is the twelfth astrological sign in the Zodiac. It spans the 330° to 360° of the zodiac. The Sun transits this area on average between February 19 and March 20.
Lets look at the constellations
What is a constellation?
Constellations
Page 51 in the ISN
On page 50, use 12 index cards and draw out the 12 zodiac constellations (name on one side, asterism on the other). Attach them as a flip out on the page.
Homework
- Capricorn (the "sea-goat") is the tenth astrological sign in the zodiac. It spans the 270–300th degree of the zodiac. The Sun transits this area from December 22 to January 19 each year.
- It is the smallest constellation in the Zodiac.
- Sagittarius (the "archer") is the ninth astrological sign, and spans 240–270th degree of the Zodiac. The Sun transits this sign between November 23 and December 21.
- The center of the Milky Way lies in the westernmost part of Sagittarius.
- Scorpio (the "scorpion") is the eighth astrological sign in the Zodiac. It spans the 210–240th degree of the zodiac. The Sun transits this area on average between October 24 and November 22.
- It contains many bright stars, including Antares.
- Libra (the "scales") is the seventh astrological sign in the Zodiac. It spans the 180–210th degree of the zodiac. The Sun transits this area between September 23 and October 22.
- It is fairly faint, Beta Librae is the brightest star in the constellation.
- Aries (meaning "ram") is the first astrological sign in the Zodiac, spanning the first 30 degrees of celestial longitude.
- Aries is a relatively dim constellation, possessing only four bright stars: Hamal, Sheratan, Mesarthim, and 41 Arietis.
- Virgo (the "maiden") is the sixth astrological sign in the Zodiac. It spans the 150-180th degree of the zodiac. The Sun transits this area on average between August 23 and September 22.
- It is the second largest constellation in the sky. It can be easily found through its brightest star, Spica.
- Taurus (meaning "the bull") is the second astrological sign in the present Zodiac. It spans the 30-60th degree of the zodiac.
- The red giant Aldebaran is the brightest star in the constellation. In the northwest part of Taurus is the supernova remnant Messier 1, more commonly known as the Crab Nebula.
- Leo (the "lion") is the fifth astrological sign of the zodiac, originating from the constellation of Leo. It spans the 120-150th degree of the zodiac. The Sun transits this area on average between July 23 and August 22 each year.
- Leo is easily recognizable due to its many bright stars.
- Gemini (meaning "the twins") is the third astrological sign in the Zodiac. The Sun transits this sign between May 21 and June 21.
- The easiest way to locate the constellation is to find its two brightest stars Castor and Pollux.
- Cancer ("the Crab") is the fourth astrological sign. It spans the 90-120th degree of the zodiac. The Sun transits this area on average between June 22 and July 22.
- Its stars are rather faint, with the brightest star being Beta Cancri.
Zodiac Constellations
History of Astronomy