On 29 June you observe the star Achernar at...

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Question 1 of 2066636eea28f7522a1c51addf

On 29 June you observe the star Achernar at a sextant altitude (Hs) of 54° 18.9'. The index error is 4.7' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)?

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Question 1 of 20

66636eea28f7522a1c51addf

On 29 June you observe the star Achernar at a sextant altitude (Hs) of 54° 18.9'. The index error is 4.7' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)?

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🔍 Key Concepts

• How to correct sextant altitude (Hs) to get observed altitude (Ho) • The sign and meaning of index error off the arc • Effect of height of eye on the dip correction and whether it is added or subtracted

💭 Think About

• Start from Hs and apply the index correction: with index error off the arc, should you add or subtract to get Ha (apparent altitude)? • Next, think about dip: does height of eye make the horizon appear higher or lower, and therefore is dip correction applied as a minus or plus? • After index correction and dip, consider whether any additional corrections (like refraction) are needed to reach Ho for a star on this type of exam problem.

✅ Before You Answer

• Be sure you know the correct sign convention for index error when it is stated as "off the arc" • Confirm the direction of dip correction for a real horizon (height of eye 58 feet) • Track every step clearly: Hs → Ha (after index) → Ho (after dip and any other required corrections) and compare your numerical result with the choices.

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Question 1 of 2066636eea28f7522a1c51addf

On 29 June you observe the star Achernar at a sextant altitude (Hs) of 54° 18.9'. The index error is 4.7' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)?

Back

Question 1 of 20

66636eea28f7522a1c51addf

On 29 June you observe the star Achernar at a sextant altitude (Hs) of 54° 18.9'. The index error is 4.7' off the arc. The height of eye is 58 feet. What is the observed altitude (Ho)?

No comments yet

Be the first to share your thoughts!

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

🔍 Key Concepts

💭 Think About

✅ Before You Answer

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

Quick actions

— No credit card needed