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

Question 1 of 2707066636eea28f7522a1c51b3ff

You observe the lower limb of the Sun at a sextant altitude (hs) of 24° 00.7' on 10 January. The index error is 2.6' off the arc. The height of eye is 55 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 24° 00.7' on 10 January. The index error is 2.6' off the arc. The height of eye is 55 feet. What is the observed altitude (Ho)?

🔍 Key Concepts

• How to apply index error that is "off the arc" (is that a positive or negative correction to hs?) • How to compute and apply the dip correction for a 55‑foot height of eye to get from apparent altitude (Ha) to observed altitude (Ho) • What extra corrections are needed when shooting the lower limb of the Sun on a given date (refraction, semidiameter, etc.)

💭 Think About

• Start from the given sextant altitude (hs). In what order do you apply index correction, dip, and the Sun’s additional corrections to arrive at Ho? • For an index error of 2.6' off the arc, should you add or subtract 2.6' from hs? Think about what the sextant reads when the index is set at zero. • With a 55 ft height of eye, is the dip a large or small correction in minutes, and is it added or subtracted?

✅ Before You Answer

• After applying index correction, check whether your corrected altitude is slightly higher or lower than hs and whether that makes sense for "off the arc". • Make sure your dip correction is in the right units (minutes of arc) and that you’re using feet, not meters, for the given formula or table. • Confirm that the Sun’s lower limb corrections (refraction + semidiameter, and any small additional terms) move your Ha in the correct direction before you compare to the multiple‑choice options.