Lecture 4: Observing the Universe and Astronomy in Antarctica

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Lecture 4Observing the UniverseandAstronomy
in Antarctica

• Dr Michael Burton

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The Nature of Light

• Light travels through space at a finite speed
• 300,000 kilometres per second.
• Wavelength of visible light is associated with
  its colour.
• So is Temperature (bluehot, redcold).
• Radio waves, infrared, visible light, x-rays are
  all part of the electromagnetic spectrum.
• Objects change appearance with wavelength

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The Spectrum

• Light can be split into a spectrum by a prism.
• The spectrum of light from a star consists of
• Continuum radiation (colours) due to its
  temperature,
• Dark lines from absorption by (cool) elements,
• Bright lines from emission by (hot) elements.
• Provides a fingerprint to identity.

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Telescopes

• Light is bent or refracted by a lens.
• Curved mirrors also focus light.
• Telescopes collect and focus light and
• Brighten,
• Resolve,
• Magnify astronomical objects.
• Refracting and Reflecting Telescopes.

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The Earths Problem Atmosphere

• Only passes visible, radio and some infrared
  radiation.
• Causes stars to twinkle.
• Emits radiation, especially in infrared (heat)
• Has weather!

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Recent Innovations

• Electronic (CCD) detectors instead of
  photographic plates.
• Detectors for new wavebands (eg infrared).
• Adaptive optics to take out atmospheric blurring
  or seeing.
• New engineering technology allows giant mirrors
  (8-10m) to be built.
• Satellites.

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Limits to Progress in Astronomy

• Technology
• Poor atmospheric transmission
• Local sources of interference
• Thermal background
• Choice of observing site
• Desert mountain tops
• Space
• Antarctic Plateau

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Observatories of the World

• Royal Observatory Edinburgh (city)
• Siding Spring Observatory
• AAT, Schmidt, 2.3m, UNSW APT
• Mauna Kea Observatory, Hawaii
• UKIRT, Keck, Gemini, JCMT,
• La Silla Observatory, Chile
• Australia Telescope
• Parkes, Narrabri, Mopra
• Space Telescopes

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Antarctica

• High ice plateau
• 2900m at South Pole to 4300m at Dome Argus
• Extremely cold
• Average temperature -50C to lt -90C
• Exceedingly dry
• By far driest desert on Earth
• Low wind speeds
• Katabatic wind lt 5 m/s

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Potential of Antarctic Astronomy

• Darkest sky
• Less heat radiation in infrared.
• Driest air
• Improved transmission from less water.
• Steadiest air
• No diurnal cycle, stable weather.
• Clearest air
• Minimal interference

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South Pole Astronomy Projects

• USA, Australia, Germany, Sweden
• CARA (Photon astronomy)
• SPIREX infrared
• AST/RO sub-millimetre
• VIPER cosmic microwave background
• AMANDA (particle astronomy)
• Neutrinos
• Cosmic Rays
• AASTO Site Testing

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UNSW at the South Pole

• Site testing experiments 19941997
• Jamie Lloyd wintered 95/96.
• SPIREX/Abu 19981999.
• Infrared camera telescope.
• AASTO since 1998
• Automated, mobile site testing observatory.

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The Future?

• AASTO to Dome C in 2002
• Douglas Mawson Telescope
• 2m Telescope at Dome C in 2004??
• And eventually.
• The Ultimate Earth-Based Observatory at Dome
  Argus