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Re: Using sun compass for calibrating boat compass
From: Bill B
Date: 2014 Jun 19, 16:00 -0400

On 5/8/2014 4:01 PM, Greg Rudzinski wrote: > If an azimuth were taken at the same time as a prime vertical > observation then the assumed longitude could be replaced by that of the > reduced LOP. Meridian angle is then improved so that a more exact > calculated azimuth can be determined by formula: > > Z = (Cos d) (Sin t) / (Cos Ho) > Greg Thank you. Played with the formula you provided above with the azimuth a few degrees off prime vertical, as well as spot on. Z would inevitably be a value a tad over or under 1. That caused me to conjecture that I wanted the sine or cosine of Z. For values over 1 I used the inverse. That seemed to agree with standard calculations of azimuth for bodies a few degrees off the prime vertical if I added or subtracted the cosine angle from 90 or 270. It seemed to fall short if the body was on the prime vertical. What am I missing? Bill B

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