Celestial Navigation · The Nautical Almanac — v Correction
The 'v' correction in the Nautical Almanac (for the moon and planets) accounts for:
- AThe observer's height of eye
- BAtmospheric refraction near the horizon
- CThe body's actual rate of change of GHA differing from the standard tabulated rate✓ Correct
- DThe semidiameter of the sun
Explanation
The v value is the difference between the body's real hourly motion in GHA and the constant rate assumed in the increment tables. The v correction (always added for planets and the moon; the sun has none) adjusts the GHA. It is read from the same Increments page as the GHA increment.
Authority: Nautical Almanac, Increments and Corrections
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