A parallax correction is NOT applied to...

Question 1 of 2707066636ee928f7522a1c519df2

A parallax correction is NOT applied to observations of which celestial bodies?

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Question 1 of 27070

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A parallax correction is NOT applied to observations of which celestial bodies?

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🔍 Key Concepts

• Parallax is the apparent shift in a celestial body's position caused by observing from the Earth’s surface instead of from the Earth’s center • Different celestial bodies are at very different distances from Earth (nearby vs very far) • For some bodies, the parallax angle is so small it is often treated as zero in practical navigation tables

💭 Think About

• Think about which body appears to move the MOST against the background stars when observed from different points on Earth: which one is closest? • For very distant objects, how big would the parallax angle be when you move from the Earth’s center to the surface? Large enough to matter, or effectively negligible? • Which type(s) of bodies does the Nautical Almanac already give corrections for, and which type(s) are assumed to have no significant parallax in typical sight reductions?

✅ Before You Answer

• Compare the relative distance from Earth of the Moon, Sun, planets, and stars • Consider for each option whether the parallax correction is large, small but non‑negligible, or effectively zero for marine navigation • Recall which bodies’ tabulated values in sight reduction tables assume no parallax correction is needed by the navigator