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sun dog

A halo in the form of a colored spot at the same angular elevation as the sun. The lunar counterpart is a paraselene. The most common parhelia are seen about 22° on either side of the sun. That angular distance increases from 22° when the sun is on the horizon to over twice that when the sun climbs to 60°. The sun side of a parhelion is reddish. The parhelia of 22° can be explained by refraction in hexagonal crystals falling with principal axes vertical. The effective prism angle is 60° when the sun is on the horizon, but this increases as the sun climbs, resulting in greater displacement of the parhelion.

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  • ส่วนหนึ่งของคำพูด: noun
  • อุตสาหกรรม/ขอบเขต: Weather
  • Category: Meteorology
  • Company: AMS

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