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Subject: Re: Sextant Accuracy
From: Bruce Stark (Stark4677@XXX.XXX)
Date: Mon Mar 17 2003 - 11:48:01 EST
Fred,
Supposing you're bringing the lower limb of the sun to the upper edge of the
reflection in the water, a visual phenomenon called "irradiation" could put
you north of the truth. Irradiation makes a bright object seem bigger than it
really is. When I measure the sun's diameter on and off the arc to check
index correction, the average of the measurements is always greater than the
true diameter of the sun.
Bruce
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