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Old 13-05-2016, 06:58 PM
casstony
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casstony is offline
 
Join Date: Feb 2006
Location: Warragul, Vic
Posts: 4,494
Equilibrium with the environment is what you want. Cooldown refers to cooling the scope down to the surrounding air temperature; until equilibrium is reached the temperature differential causes air currents and distorts optics which disrupt the view and limits your magnification. Atmospheric turbulence also limits magnification achievable on a given night.
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