Question 1519Navigation General

The correct answer is C) using a dip correction based on the height of eye above the ice. In high latitudes, when the horizon is obscured by pack ice, the sun's lower limb can be brought tangent to the ice surface to obtain a celestial observation. To account for the height of the observer's eye above the ice, a dip correction must be applied to the observed altitude. This dip correction is based on the height of eye above the ice, as outlined in navigation references such as Bowditch's The American Practical Navigator. The other options are incorrect because: A) adding 30° of arc is not the appropriate correction, B) doubling the semidiameter correction is also not the correct method, and D) using table 22 in Bowditch Vol. II would not be applicable, as that table is for determining dip over open water, not ice-covered horizons.