The phase correction should be applied to sights of Venus and Mars __________.
Official USCG Answer & Rule Citation
Correct Answer: Option B — during twilight observations only
The Nautical Almanac instructs that phase corrections for Venus and Mars account for asymmetrical illumination of the planetary disk and are applied only during twilight when the planet is viewed against a dark background.
100% Free & Open Access — No daily limits, paywalls, or gated answers on BrightMariner.