Question 1 of 2921866636eea28f7522a1c51ae47

On 7 May you observe Polaris for latitude at 0303 ZT. Your DR position is LAT 56° 35.4' N, LONG 05° 38.9' W. The sextant altitude is 56° 11.1'. The height of eye is 36', and the index error is 3.3' off the arc. What is the latitude at the time of the sight?

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Question 1 of 29218
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On 7 May you observe Polaris for latitude at 0303 ZT. Your DR position is LAT 56° 35.4' N, LONG 05° 38.9' W. The sextant altitude is 56° 11.1'. The height of eye is 36', and the index error is 3.3' off the arc. What is the latitude at the time of the sight?

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🔍 Key Concepts

• Using Polaris to determine latitude in the Northern Hemisphere • Applying sextant corrections: index error, height of eye, refraction, and Polaris tables (a0, a1, a2) • Understanding the relationship between corrected altitude of Polaris and observer’s latitude

💭 Think About

• How do you correct the sextant altitude (Hs) to get the true observed altitude (Ho), step by step, using index error and height of eye? • Once you have Ho for Polaris, how do you use the Polaris correction tables (a0, a1, a2) for the given date and longitude to get latitude? • Compare your final computed latitude to the DR latitude: does the answer seem reasonable for a single Polaris sight near upper transit?

✅ Before You Answer

• Be sure you apply index error with the correct sign: "+ off the arc" vs "+ on the arc" and how that affects Hs. • Confirm that dip (height of eye) is always subtracted from Hs before applying other altitude corrections. • Verify you are using the correct Polaris table entries for 7 May and 5°–6° W longitude, and that you add/subtract them in the right order to get latitude.