Question 1772Navigation General

The correct answer is D) 87°. When the Hc (calculated altitude) exceeds the Ho (observed altitude) by 87° or more, the line of position should be plotted as a circle around the geographic position of the celestial body. This is because when the difference between the calculated and observed altitudes is greater than 87°, the position line becomes ambiguous and cannot be reliably plotted as a straight line. Plotting it as a circle around the GP provides a more accurate representation of the potential position of the observer. The other answer choices of 80°, 83°, and 85° are incorrect because they do not meet the 87° minimum threshold for plotting the line of position as a circle.