🔍 Key Concepts

• Navigational triangle on the celestial sphere (zenith, celestial pole, GP of the body) • Difference between azimuth, meridian, and altitude in celestial navigation • Angles measured at the pole versus angles measured at the observer

💭 Think About

• Ask yourself: Which of these choices is specifically defined as the angle at the elevated pole between two meridians? • Which terms here refer to directions on the horizon, which refer to angles at the pole, and which belong more to astronomy than to standard marine celestial navigation terminology? • Visualize the spherical triangle formed by the pole, the observer’s zenith, and the body’s GP: where is each angle located and what is each one usually called?

✅ Before You Answer

• Confirm which option’s definition involves the elevated pole and two meridians (observer’s and body’s). • Eliminate any terms that are clearly associated with horizon-based measurements (up/down or around the horizon). • Check which term is commonly linked to right ascension/declination systems rather than the standard altitude/azimuth triangle used in marine navigation.