Ptolemy originally defined 48 constellations that were used by later astronomers and navigators. These constellations represented gods and figures from mythology and were used as a celestial calendar. In the early 20th century, the IAU standardized 88 constellations still used today to provide consistency for astronomers globally. Though constellations have evolved over millennia of human observation, their patterns continue to help people explore and understand the night sky.

3. Ptolemy listed 48 constellations in his
Almagest.
21 Northern Constellations
Andromeda, Aquila, Auriga, Boötes, Cassiopeia, Cepheus, Corona
Borealis, Cygnus, Delphinus, Draco, Equuleus, Hercules, Lyra, Ophiuchus,
Pegasus, Perseus, Sagitta, Serpens, Triangulum, Ursa Major, Ursa Minor
12 Zodiacal Constellations
Aries, Aquarius, Cancer, Capricornus, Gemini, Leo, Libra, Pisces,
Sagittarius, Scorpius, Taurus, Virgo
15 Southern Constellations
Ara, Argo Navis, Canis Major, Canis Minor, Centaurus, Cetus, Corona
Australis, Corvus, Crater, Eridanus, Hydra, Lepus, Lupus, Orion, Pisces
Austrinus

6. ROLES
 Represented the Gods and their symbols
 Farming Calendar and rustic activities
These figures developed in stages from 3200 BC – 500 BC
The most important in the divine set was the 12 Zodiac Signs plus
several associated animals ∆ serpent, crow, eagle and fish ∆

7.  Where the earliest direct evidence for the
constellation comes from inscribed stones and
clay writing tablets dug up.
 1300 – 1000 B.C were Mesopotamian
constellations were created
 There are Babylonian star catalogues
o MUL.APIN – a text dating to the Late Bronze Age
(14th – 12th century BC) which include the farming
calendar tradition that gives an accurate divine
associations of constellation.
o Venus Tablet of King Ammizaduga

9.  Orion correlation theory
According to Egyptian mythology, the gods descended from
the belt of Orion and Sirius– the brightest star in the sky. The
ancient Egyptian civilization firmly believed that from Sirius and
Orion beings came in the form of humans– Osiris and Isis and
they instigated the human race.
The concept that the three pyramids at Giza are in a special
alignment of Orion’s Belt is amazing.
Why does the Great Pyramid have air shafts that point to Orion?
These are just some of the question that– until today, do not
have a clear answer.

12.  The Modern Constellation in this region were defined during the
Age of Exploration. In 1919 a group of astronomers formed the
International Astronomical Union or IAU. One of the first items they
tackled was the celestial disarray. The IAU made a list of 88 'official'
constellations in 1922 and approved the boundary of each six
years later.
 The 88 official constellations chosen by the IAU were all of
European origin because those constellations were already well
known and used by many professional astronomers.
 The official constellations are no more and no less important than
the constellations of any other time, country, or culture. What they
are is the common language for astronomers around the world.
Think of the world's spoken languages - there is no best or correct
language and each conveys some meanings better than others.
Still, English is becoming the lingua franca and like English the
official constellations are a useful tool for international
communication.

14.  Common Names
 The Bayer Naming System
 The Flamsteed Naming System

15. Constellations are useful because they can help people to
recognize stars in the sky. By looking for patterns, the stars and
locations can be much easier to spot.
The constellations had uses in ancient times. They were used
to help keep track of the calendar. This was very important so
that people knew when to plant and harvest crops.
Another important use for constellations was navigation. By
finding Ursa Minor it is fairly easy to spot the North Star (Polaris).
Using the height of the North Star in the sky, navigators could
figure out their latitude helping ships to travel across the
oceans.

16.  The largest constellation by area is Hydra which is
3.16% of the sky.
 The smallest is Crux which only takes up 0.17 percent
of the sky.
 Small patterns of stars within a constellation are
called asterisms. These include the Big Dipper and
Little Dipper.
 The word "constellation" comes from a Latin term
meaning "set with stars."

18.  http://adsabs.harvard.edu/abs/1998JBAA..108....9R
 http://www.ducksters.com/science/physics/constellations.php
 http://www.modernconstellations.com/constellationhistory.html
 http://www.modernconstellations.com/celestialmaps.html
 http://www.modernconstellations.com/constables.html
 http://en.wikipedia.org/wiki/Constellation
 http://articles.adsabs.harvard.edu/cgi-bin/nph-
iarticle_query?bibcode=1998JBAA..108....9R&db_key=AST&page_ind=1&plate_select=NO&data_type=GI
F&type=SCREEN_GIF&classic=YES