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Nature's Wonders - Optical Phenomenon
Sun dogs hovering over Hong Kong 
The mysterious glory 
Colours of Clouds 
Triple rainbow 
Echoes of the rainbow 
What is Cerenkov Radiation? 
In-depth anatomy of the atmospheric optical phenomenon - "Sun dog" 
Why is candlelight yellow and gas-grill light blue? 
  What are primary colours?
  Why do stars twinkle?
  What is the colour of water?
  Which is darker - coarse sand or fine sand?
  Why are spectacles or camera lens so difficult to clean?
  Red Eye and 'Glory'
  Why do breaking waves appear white?
  Why does wet sand look darker than dry sand?
  Obscured hills - why is a distant hill less distinct than a near one?
  Why is the sky blue?
  What causes a rainbow?
  Why is the region outside the primary rainbow much darker than that inside the primary rainbow?
The Hong Kong Observatory provides sky images (Solar halo on 8 May 2002)
What is "Halo"? (Solar Halo on 5 March 1998)

Last revision date: <10 Apr 2014>