Celestial Navigation · Polaris
Polaris is useful for a quick latitude because it:
- AStays close to the north celestial pole, so its altitude approximates latitude✓ Correct
- BLies on the celestial equator
- CIs the brightest star in the sky
- DHas zero declination
Explanation
Because Polaris is within about 1° of the pole, its corrected altitude is approximately the observer's latitude; the small a0/a1/a2 corrections reduce it exactly to the pole. It is only visible in northern latitudes.
Authority: Bowditch (Pub. No. 9); The Nautical Almanac Polaris tables
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