### Fit-Slope Method to Analyze Sextant Sights

We have been teaching what we named the Fit-slope Method for analysing sextant sights since 1978, and it has appeared in all of our textbooks since then. Consequently we were pleased and honored that this method was referenced in the latest edition of Bowditch's

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For any measurement, we always get a more realistic value by making several independent measurements and then averaging the results—or maybe even applying more sophisticated statistical analysis such as least squares. This is no different in celestial navigation when we measure the sextant height of a star from which we can compute a line of position (LOP) on the chart. We do not want to…

*American Practical Navigator*, which in turn led me to realize that we do not have an explanation of this method in public that is easy to reference, although I did post a note related to it. That note, and the Bowditch description, are short, and do not emphasize the key aspect of the method. This note is intended to remedy that.* * *

For any measurement, we always get a more realistic value by making several independent measurements and then averaging the results—or maybe even applying more sophisticated statistical analysis such as least squares. This is no different in celestial navigation when we measure the sextant height of a star from which we can compute a line of position (LOP) on the chart. We do not want to…