Celestial Navigation · Sextant Corrections — Dip
Your height of eye is 64 feet. Using dip ≈ 0.97 × √height (feet), what is the dip correction (and its sign)?
- A+7.8' (additive)
- B−7.8' (always subtractive)✓ Correct
- C−5.0'
- D−12.5'
Explanation
Dip ≈ 0.97 × √64 = 0.97 × 8 = 7.76 ≈ 7.8'. Dip corrects for the observer's height above sea level depressing the visible horizon and is always subtracted from the sextant altitude.
Authority: Nautical Almanac, dip table; Bowditch (Pub. No. 9)
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