Celestial Navigation · Time — Arc to Time
Convert a longitude of 105°W to time using the rate 15° = 1 hour.
- A6h 00m
- B7h 00m✓ Correct
- C7h 30m
- D10h 30m
Explanation
Earth rotates 15° of arc per hour, so 1° = 4 minutes of time. 105° ÷ 15 = 7 hours exactly. West longitude lies behind Greenwich in time.
Authority: Nautical Almanac, Arc-to-Time table; Bowditch (Pub. No. 9)
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