Right ascension is primarily used by the...

Right ascension is primarily used by the navigator for __________.

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🔍 Key Concepts

• Right ascension (RA) is an astronomical coordinate measured along the celestial equator from the First Point of Aries • Difference between right ascension and sidereal hour angle (SHA) in celestial navigation • How a navigator uses star data from almanacs or precomputed tables for star identification and sight planning

💭 Think About

• Which of the choices involves using a star’s position referenced to the First Point of Aries, rather than directly to the vernal equinox or local hour angle? • Think about which resource or method (Ageton tables, amplitudes, star finder, or Pub 249) actually lists or depends on right ascension values instead of SHA or declination alone. • Ask yourself: when planning or selecting stars for sights, which of these tools requires an astronomical coordinate system input like RA rather than only geographic or angular relationships?

✅ Before You Answer

• Identify which option deals specifically with precomputed star data and selection of suitable stars for observation. • Recall which systems (great circle sailing, amplitudes, star finders, Pub 249) normally use SHA and declination versus right ascension and declination. • Verify in your study materials which publication’s tables are organized by right ascension; that’s the one RA is primarily used to enter.

🔍 Key Concepts

💭 Think About

✅ Before You Answer