On 14 March your 1846 ZT DR position is LAT...

Study

Question 1 of 2066636eea28f7522a1c51aac1

On 14 March your 1846 ZT DR position is LAT 21°57.6' N, LONG 132°16.2' W. At that time, you observe Polaris with a sextant altitude (hs) of 22°16.8'. The chronometer time of the sight is 03h 45m 10s, and the chronometer error is 01m 32s slow. The index error is 3.2' off the arc, and the height of eye is 44.9 feet. What is your latitude by Polaris?

Back

Question 1 of 20

66636eea28f7522a1c51aac1

No comments yet

Be the first to share your thoughts!

If the question has a related picture, it will appear here.

🔍 Key Concepts

• Corrections to sextant altitude (hs): index error, height of eye (dip), and altitude corrections to find observed altitude (Ho) • How Polaris is used to find latitude: Ho of Polaris is approximately equal to latitude, with small corrections for date and longitude (LHA Aries) • Using the DR latitude and Polaris tables (or factor for 2020s era exams, but here think in terms of small corrections to Ho)

💭 Think About

• First, carefully reduce the sextant altitude (hs) to get Ho: are you adding or subtracting each correction, and are your units in minutes or degrees and minutes? • Once you have Ho of Polaris, compare it to your DR latitude. Should the latitude by Polaris be slightly higher or lower than your DR latitude based on the corrections for date and position? • Look at the answer choices: which ones are consistent with only a small adjustment (less than about 1°) from your DR latitude?

✅ Before You Answer

• Be sure you handle index error sign correctly: "off the arc" versus "on the arc" (does it get added or subtracted?) • Confirm the dip (height of eye) correction direction: it is always subtracted from hs • After getting Ho, verify that your final latitude is reasonable: it should be close to both Ho of Polaris and your DR latitude, not dramatically different

👋 Hi! I'm Genie, your AI study assistant. How can I help you with this question?

Quick actions

— No credit card needed