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

Question 1 of 2707066636eea28f7522a1c51b40b

You observe the lower limb of the Sun at a sextant altitude (hs) of 41°29.8' on 11 January. The index error is 2.4' off the arc. The height of eye is 68 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 41°29.8' on 11 January. The index error is 2.4' off the arc. The height of eye is 68 feet. What is the observed altitude (Ho)?

🔍 Key Concepts

• How index error off the arc affects the sextant altitude reading (sign of index correction) • How to find and apply dip correction for a height of eye of 68 feet • How the main altitude correction for the Sun’s lower limb (semi‑diameter, refraction, parallax) changes the apparent altitude to the observed altitude Ho

💭 Think About

• Start from the given sextant altitude (hs). What is the correct sign of the index correction when the error is 2.4' off the arc? Does this make ha larger or smaller? • Convert the height of eye to a dip correction using tables or formula. Should dip be added or subtracted from the horizon altitude? • Once you have apparent altitude (ha), think about the combined Sun correction on 11 January for the lower limb around 41°. Is the net correction likely positive or negative, and roughly how many minutes?

✅ Before You Answer

• Be sure you have the correct sign for index correction: it is the opposite of the index error (off the arc vs on the arc). • Confirm that dip is always subtracted for a normal sea horizon sight with a positive height of eye. • Check your final Ho against the choices: does it reflect a reasonable total correction from hs (index + dip + Sun corrections), on the order of a few minutes, not tens of minutes?