The correction applied to observed attitudes of Polaris to compensate for its displacement from the north celestial pole when obtaining latitudes by sextant. For example, in the Northern Hemisphere, the star Polaris (declination 89°10'N) is close to the north celestial pole (NCP). If observation of Polaris is taken, the altitude obtained (HO) will be in error by a very small amount. Hence, a small correction called correction Q is applied to the angle of Polaris to get the altitude of NCP, which is the same as the latitude of the observer.
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