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 People
can see planets and stars in the night
sky. Rock-art paintings in caves in Europe show
that people observed and recorded stars and
planets even before writing was invented.
 Egyptians
were highly advanced in their
knowledge of astronomy.
 Different
cultures have identified and named
certain constellations.
 Some
them.
constellations have stories attached to
 Patterns
of stars in the sky are called
constellations.
 There are 88 main constellations visible
from Earth.
 Many, but not all, constellations can be seen
from South Africa. We see different
constellations in winter and summer.
 The smallest constellation is the Southern
Cross or Crux. It only has four very bright
stars.
 Constellations have different names around
the world.
 People
can see more detail in the sky
when they use a telescope.
 The first telescope was developed by
a Dutch eyeglass maker in 1607.
 A telescope forms an image of the
object and magnifies it (makes it look
bigger)
 There are different types of
telescopes including:
 Optical
telescopes
 Radio telescopes
Watch video clip: How it’s made - Telescopes
 Optical
telescopes receive light and focus it by
refraction (using lenses) or reflection (using
mirrors) such as SALT (South African large
telescope) & Hubble telescope in space.
SALT: South African Large Telescope
The
largest single optical
telescope in the southern
hemisphere.
It is a reflecting telescope.
Situated near Sutherland (Karoo)
Northern Cape
Site was chosen due to dark, clear
skies, good weather & low
humidity.
Watch video clip: The South African Large Telescope
 The
Earth’s atmosphere stops us from
getting the best images of distant bodies
in space.
 The atmosphere can bend or distort light
coming from the stars as dust and water
vapour are found in high concentrations in
the atmosphere.
 Telescopes have been sent into space and
now work as satellites (orbit the Earth)
that constantly take pictures of distant
bodies.
 These pictures are then sent back to
scientist on Earth.
The
most famous of the space
telescopes.
It was sent into space in 1990.
It has taken nearly 600 000
photographs of the universe.
Hubble must be serviced by
astronauts taken
into space on a
shuttle spacecraft.
The
telescope is 13.2 meters
long, weighs 11 110 kilograms
and cost R34 billion.
Hubble's six cameras and sensors
see visible, infrared and
ultraviolet light. At the heart of
Hubble is its
2.4 meter diameter
primary mirror.
 Radio
telescopes receive radio waves and focus
them by reflection (typically using a metal
receiving dish) such as the SKA (Square
Kilometre Array), KAT-7 and MeerKAT.
 Scientists
have discovered that all bodies in
space (e.g. stars / planets) give out radio
waves.
 Radio telescopes do not have lenses or
mirrors and we do not look through them.
 Radio telescopes need to be far away from
cell phones and radio networks.
 One radio telescope can only collect a small
amount of information.
 A group of radio telescopes working
together is called an ARRAY of telescopes.
KAT-7, MeerKAT and SKA
 South Africa has a number of large radio
telescopes.
KAT-7
 Built in the Karoo.
 KAT-7 is part of the MeerKAT array.
 MeerKAT is the precursor to the SKA project
SKA [To be completed in 2025]
 Square Kilometre Array
 1000’s of individual telescopes.
 Will be the most powerful telescope ever built.
 Karoo weather conditions are perfect.
 Weather
must be clear – no clouds
 Air above telescope must be still, not moving.
 Air should be dry.
 Amount of water (humidity) in the air must be
low.
 Sky must be dark – no light pollution
 Telescope should be at a high altitude above
sea level [Atmosphere distorts image.].

South Africa has many locations that meet
these requirements
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