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Refraction Corrections
Updated 12/23/2001

When using Polaris as a polar alignment reference, atmospheric refraction effects may need to be factored in, particularly at low latitudes. The charts below shows the refraction correction at sea level for various latitudes. The correction should be subtracted from the apparent elevation of the celestial pole (via observations of Polaris) to obtain the true elevation of the celestial pole. Maximum refraction at 0° (equator) is ~34-1/2 minutes.

Refraction at high latitudes.

Refraction at lower latitudes, graphed in greater detail.

Copyright 2001 by David A. Kodama