🔍 Key Concepts

• Navigational triangle on the celestial sphere (zenith, celestial pole, and celestial body) • Meaning of the elevated pole for your latitude (N or S) • Names of the angles at each corner of the navigational triangle (pole, zenith, and body)

💭 Think About

• Which two points (out of zenith, celestial pole, and celestial body) define the sides that meet at the elevated pole? What is the traditional name of that angle in navigation texts? • Think about which angle name is associated with the observer’s meridian, and which one is associated with the vertical circle through the body. • Eliminate any choices that are clearly not angles in the PZX navigational triangle used in nautical astronomy.

✅ Before You Answer

• Verify the definition of azimuth angle (what points does it connect?). • Verify the definition of meridian angle (how is it measured and from where?). • Confirm which term, if any, is NOT normally used in nautical astronomy but in general astronomy/astrophysics instead.