When correcting the sextant altitude to...

When correcting the sextant altitude to...

Question 1 of 2707066636ee928f7522a1c519430

When correcting the sextant altitude to apparent altitude you are correcting for inaccuracies in the reading and __________.

Question 1 of 27070

Q

When correcting the sextant altitude to apparent altitude you are correcting for inaccuracies in the reading and __________.

🔍 Key Concepts

• Sextant altitude corrections sequence: observed height (Hs) → apparent altitude (Ha) → true altitude (Ho) • Which corrections are applied first: index error and dip vs refraction, semidiameter, parallax • The difference between errors caused by the instrument/observer setup and errors caused by the light path or the body itself

💭 Think About

• Think about what the sextant physically measures: it uses the visible horizon and your eye height. What kind of error does that introduce? • Ask yourself: when going from sextant altitude to apparent altitude (not yet true altitude), which group of corrections are you applying, early in the process or later in the process? • Which option best matches the idea of correcting for the fact that your horizon is not at the same level as if your eye were right at sea level?

✅ Before You Answer

• Identify which choice relates to reference level of the horizon/observer, not the center of the Earth or the celestial body • Recall that refraction and semidiameter are usually applied after you’ve already found apparent altitude • Eliminate any choice that talks about the center of the Earth or center of the body, because those are part of later corrections toward true altitude, not apparent altitude