Celestial Navigation · Polaris — Azimuth
Besides giving latitude, why is Polaris useful for checking compass error in the Northern Hemisphere?
- AIt is the brightest star in the sky
- BIt rises and sets due east and west daily
- CIt has zero declination
- DIts azimuth is always very close to 000° (true north), so the almanac's Polaris azimuth gives a quick compass check✓ Correct
Explanation
Polaris lies within about 1° of the north celestial pole, so its true azimuth is always near 000°. The almanac gives a precise Polaris azimuth that, compared with the observed compass bearing, yields the compass error directly.
Authority: Nautical Almanac, Polaris azimuth table; Bowditch (Pub. No. 9)
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