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Name: Eran H.
Status: N/A
Age: 40s
Location: N/A
Country: N/A
Date: Thursday, April 25, 2002


Question:
Why distant lights (for example, when looking at a near-by town 10 km distance at night)seem to be blinking rather than stable?


Replies:
This blinking, which is also seen when you look at stars at night, is caused by the convection of the atmosphere. The varying density changes the index of refraction slightly which alters the path of the light beam that strikes your eye. This is one of the main reasons why telescopes are located on high mountains -- to reduce the air pressure and reduce these fluctuations.

Vince Calder



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