Transcript Slide 1

Constellations
http://www.hope.co.nz/projects/stars/stars_ss_dx_org.jpg
What is a constellation?
A constellation is a group of stars that
are connected together to form a
figure or picture.
• The term is also used to mean any
group of stars visibly related to each
other
• Considered as a fixed configuration or
pattern in a particular culture.
• The International Astronomical Union
(IAU) divides the sky into 88 official
constellations with exact boundaries, so
that every direction or place in the sky
belongs within one constellation.
• Northern hemisphereconstellations based upon the
constellations of the ancient Greek
tradition, containing the signs of
the zodiac
http://www.fas.org/irp/imint/docs/rst/Sect20/map3+.jpg
• A star pattern may be
widely known but may
not be recognized by
the International
Astronomical Union;
such a pattern of
stars is called an
asterism.
• An example is the
grouping called the
Big Dipper.
http://www.astropix.com/IMAGES/C_SPRING/BIGDIP.JPG
• The grouping of stars into
constellations is
essentially arbitrary and
random
• Different cultures have
had different
constellations, although a
few of the more obvious
ones tend to recur
frequently, e.g., Orion and
Scorpius.
• In space, most of the stars we see have little or
no relation to one another, but can appear to be
grouped in the night sky.
•
The stars in a constellation rarely have any
astrophysical relationship to each other; they just
happen to appear close together in the sky as
viewed from Earth; they typically lie many lightyears apart in space. One exception to this is the
Ursa Major.
Some well-known
constellations contain
striking and familiar
patterns of bright stars.
Examples:
Orion (containing a figure of
a hunter)
Leo (containing bright stars
outlining the form of a
lion)
Scorpius (a scorpion)
Crux (a cross).
http://joemorris.mystarband.net/images/Orion%20Constellation.jpg
http://www.astropix.com/HTML/WIDE/CONST16.HTM
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http://www.astropix.com/HTML/WIDE/CONST09.
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http://www.astropix.com/HTML/WIDE/CONST10.HTM
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http://www.astropix.com/HTML/WIDE/CONST17.HTM