Download Core Theme 2: Constellations

Core Theme 2: Constellations
—  Use astrological star sign as a hook; constellation
identification; origin and history; myths and legends;
observing the night sky; identify stars of different types,
names and colours; investigate available astronomical
resources and how to find them.
—  Task: Observing, drawing, make up new constellation
patterns and associated stories, compare with constellations
in other countries to encourage global awareness.
Star signs and Astrology
—  So who doesn’t know their star sign?!
—  How do you think they were set?
—  Have a look at tonight's night sky image copied on
your desk today – can you see some of the signs of
the Zodiac?
For the purpose of determining the constellations in contact with the ecliptic, the
constellation boundaries as defined by the International Astronomical Union in 1930 are
used. For example, the Sun enters the IAU boundary of Aries on April 19. Needless to say, the
IAU defined the constellation boundaries without consideration of astrological purposes.
The dates the Sun passes through the 13 astronomical constellations of the ecliptic are
listed below, accurate to the year 2011. The dates will increment by one day every 70½
years, and already several have changed. The corresponding tropical and sidereal dates are
given as well.
History
—  Astrology consists of a number of belief systems
which hold that there is a relationship between
astronomical phenomena and events in the human
world.
—  In the West, astrology most often consists of a
system of horoscopes that claim to explain aspects
of a person's personality and predict future events
in their life based on the positions of the sun,
moon, and other planetary objects at the time of
their birth.
—  Many cultures have attached importance to
astronomical events, and the Indians, Chinese, and
Mayans developed elaborate systems for predicting
terrestrial events from celestial observations.
We are looking at Constellations in an
astronomical context!
—  In modern astronomy a constellation is an
internationally defined area of the celestial sphere.
There are 88 standard constellations recognised by the
International Astronomical Union (IAU) since 1922.
—  The majority go back to the original 48 constellations
defined by Ptolemy in the 2nd centaury. The remaining
were defined in the 17th and 18th century, the most
recent found in the southern sky.
—  There are also numerous historical constellations not
recognised by the IAU, or constellations from regional
traditions of astrology or astronomy such as Chinese,
Hindu and Aboriginal.
http://www.iau.org/public/constellations/
Identification
We will look at 4 constellations here:
—  Ursa Major
—  Orion
—  Pegasus
—  Taurus
—  Can you spot all four on your night sky map?
—  To observe we must first become familiar, so we
can use heavens-above.com website, Stellarium
programme, a planisphere, viewer etc.
—  When we get a clear night sky, wrap up warm, go to
a dark location and allow your eyes to become
dark-adjusted for at least 10min. Bring map/
iPhone and torch with red filter.
Ursa Major
Dominated by the Plough, the pointers point North
to Polaris. Roughly, this is the area the Hubble
Deep Field image was taken in. Ursa Major has
many cultural associations.
http://www.bbc.co.uk/programmes/p00cydkv
Orion
—  Orion a winter constellation, beautiful. Betelgeuse is a
massive M-type red supergiant star nearing the end of its
life. When it explodes (probably not in our lifetime!) it will
even be visible during the day. Rigel is a B-type blue
supergiant that is the sixth brightest star in the night sky. .
The Orion Nebula is in the Hunter’s sword.
—  http://www.bbc.co.uk/programmes/p00fd2qx
—  Sirius, (the Dog Star, not shown here) following at Orion’s
heel is the brightest star in the night sky (a binary star).
Pegasus
—  Pegasus is a constellation in the northern sky,
named after the winged horse Pegasus in Greek
mythology. It was one of the 48 constellations
listed by the 2nd-century astronomer Ptolemy.
—  Stars of Pegasus – lets look at naming etc. here:
—  α Peg (Markab), β Peg, and γ Peg, together with
α Andromedae (Alpheratz or Sirrah) form the large
asterism known as the Square of Pegasus.
—  51 Pegasi, a star in this constellation, is the first
Sun-like star known to have an extrasolar planet.
—  IK Pegasi is the nearest supernova candidate.
—  Spectroscopic analysis of HD 209458 b, an
extrasolar planet in this constellation has provided
the first evidence of atmospheric water vapor
beyond the solar system, while extrasolar planets
orbiting the star HR 8799 also in Pegasus are the
first to be directly imaged.
Magnitudes
Taurus – the Bull
—  Has many interesting components. The brightest
member of this constellation is Aldebaran, an orangehued, spectral class K5 III giant star. Its name is from
‫ان‬#$%&‫ ا‬al-dabarān, Arabic for 'the follower' (of the
Pleiades). Bull’s eye.
The Pleiades (M45)
—  or Seven Sisters (Messier object 45), is an open star
cluster containing middle-aged hot B-type stars
located in the constellation of Taurus. It is among the
nearest star clusters to Earth and is the cluster most
obvious to the naked eye in the night sky.
—  Pleiades has several meanings in different cultures
and traditions. The cluster is dominated by hot blue
and extremely luminous stars that have formed within
the last 100 million years – beautiful to look at!
Resources
—  As mentioned earlier we can use some things to first become familiar with the
night sky: heavens-above.com website, Stellarium programme, a planisphere,
viewer etc.
—  Lets look at using these now briefly to find the night sky for tonight and
perhaps what time Orion rises?
—  We can aslo use websites to get the children interested:
—  BBC Sky at night
—  http://www.bbc.co.uk/programmes/b006mk7h
—  Orion
—  http://www.bbc.co.uk/programmes/p00fd2qx
—  Plough – cultural stories
—  http://www.bbc.co.uk/programmes/p00cydkv
—  Moore Marathon e.g. Objects 17-25
—  http://www.bbc.co.uk/programmes/b006mk7h/clips
To finish my favourite story
—  Dark cloud constellations
—  The Great Rift, a series of dark patches in the Milky Way, is
more visible and striking in the southern hemisphere than
in the northern. It vividly stands out when conditions are
otherwise so dark that the Milky Way's central region “casts
shadows on the ground”. Some cultures have discerned
shapes in these patches and have given names to these
"dark cloud constellations."
—  Members of the Inca civilization identified various dark
areas or dark nebulae in the Milky Way as animals, and
associated their appearance with the seasonal rains.
Australian Aboriginal astronomy also describes dark cloud
constellations, the most famous being the "emu in the sky"
whose head is formed by the Coalsack.
—  The "Emu in the sky," a constellation defined by dark
clouds rather than the stars. An IAU interpretation
would recognise Crux (the Southern Cross) above the
emu's head and Scorpius on the left. The head of the
emu is the Coalsack.
—  Further information: Great Rift (astronomy)