You observe the lower limb of the Sun at a...

Question 1 / 27070

Question 1 of 2707066636eea28f7522a1c51b3fd

You observe the lower limb of the Sun at a sextant altitude (hs) of 22°58.6' on 16 June. The index error is 2.0' off the arc. The height of eye is 61 feet. What is the observed altitude (Ho)?

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Question 1 of 27070

You observe the lower limb of the Sun at a sextant altitude (hs) of 22°58.6' on 16 June. The index error is 2.0' off the arc. The height of eye is 61 feet. What is the observed altitude (Ho)?

🔍 Key Concepts

• How to apply index error that is "off the arc" when correcting sextant altitude (hs) to get apparent altitude (Ha) • How to compute dip (height of eye correction) for 61 feet and whether it is added or subtracted • The sequence of sight corrections: hs → Ha → Ho (sextant altitude to apparent altitude to observed altitude)

💭 Think About

• First decide whether an index error that is off the arc should be added to or subtracted from hs. What does "off the arc" mean on the sextant drum? • When you apply the dip correction for height of eye, does that correction make the altitude larger or smaller? Why does the observer’s height above sea level matter? • After applying index error and dip, consider whether there are any additional corrections needed for the Sun’s lower limb (refraction + semidiameter) to reach Ho.

✅ Before You Answer

• Be sure you apply the index error with the correct sign (off the arc vs on the arc). • Verify that the dip correction for 61 feet is computed correctly (check a dip table or the standard formula) and has the right sign. • Confirm you have moved from hs to Ha and then to Ho in the correct order, without skipping any required corrections for the Sun.