Celestial Navigation · Compass Error
An azimuth observation determines compass error by:
- AMeasuring the altitude of the body and comparing it to Hc
- BTiming how long the body takes to set
- CCounting the number of stars visible at twilight
- DComparing the body's computed true azimuth with its observed compass bearing✓ Correct
Explanation
The true azimuth (Zn) of a body is computed (or taken from azimuth tables) for the time of observation. The difference between Zn and the compass bearing of the body is the compass error — east if the compass reads low, west if it reads high.
Authority: Bowditch (Pub. No. 9)
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