Difficulty: Easy
Correct Answer: They remain always above the horizon for the observer
Explanation:
Introduction / Context:Circumpolar stars are important in navigation and surveying because they never set; their apparent motion provides useful reference directions throughout the night.
Given Data / Assumptions:
Concept / Approach:
A star is circumpolar if its declination satisfies conditions that keep its diurnal circle entirely above the horizon for that observer. Such stars circle the celestial pole without ever setting, thus are always visible (weather permitting).
Step-by-Step Solution:
Define circumpolar → star never dips below horizon.Hence, the key property is continuous visibility above the horizon.Therefore (c) is the most defining statement.Verification / Alternative check:
Diurnal circles drawn on the celestial sphere for high declinations show continuous paths above the horizon.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
They remain always above the horizon for the observer.
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