A star that never sets below the horizon for a given latitude due to near-pole position is called what?

• A. Circumpolar Star
• B. Navigational Star
• C. Circumferential Star
• D. Omnipresent Star

Answer: (A)

Circumpolar stars are those that never set below the horizon at a given latitude because they stay close to the celestial pole and their daily path stays above the horizon. As the sky appears to rotate around the celestial pole, a star will remain visible all the time if its declination is high enough relative to the observer’s latitude. The practical rule is that, in the northern hemisphere, a star is circumpolar if its declination δ satisfies δ ≥ 90° − φ, where φ is the observer’s latitude. For example, at 40°N, stars with δ ≥ 50° never set. This term precisely describes a star that remains above the horizon due to its near-pole position, which is why it’s the correct choice. The other options refer to ideas that aren’t standard terms for this celestial behavior.