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Topic: Does the tide condition effect Celestial Nav?
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Mark Callahan
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posted June 30, 2004 11:53 AM
If I take my sights from shore looking out to the sea/sky horizon, I know Dip-Short is not an issue, just height-of-eye. If I want to shoot Polaris 3 nights in a row, would I have to do it at the same tide condition (hi-lo-slack)to get the same reading?
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ann eastwood
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posted June 30, 2004 04:42 PM
Yes, you would want to correct for that if the tide change is significant. In some parts of the world the tides are 40 ft! In the Seattle area, they could easily differ thoughout the day by 10 feet. The effect of HE is essentially the square root of HE, so a 9 foot change is 3' change in Hs correction or about 3 miles error.
When on the water, however, this would not matter at all, since you are going up and down with the water.
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