Celestial Navigation · Amplitudes — Bearing
At sunrise the sun's declination is N15°00' and your latitude is 45°00'N. Using sin(amplitude) = sin(declination) ÷ cos(latitude), what is the sun's true bearing?
- A068.5°T✓ Correct
- B078.5°T
- C111.5°T
- D090.0°T
Explanation
sin(amp) = sin 15° ÷ cos 45° = 0.2588 ÷ 0.7071 = 0.366, amplitude ≈ 21.5°. At sunrise the amplitude is measured from east (090°); with north declination the sun rises north of east: 090° − 21.5° = 068.5°T.
Authority: Bowditch (Pub. No. 9), amplitudes; Nautical Almanac
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