Celestial Navigation · Sun Sight — Procedure
The essential data recorded at the instant a sun sight is taken are:
- AThe sextant altitude and the exact GMT (to the second) of the observation✓ Correct
- BOnly the compass heading
- CThe barometric pressure alone
- DThe sea temperature
Explanation
At the moment the body is brought to the horizon, the observer records the sextant altitude and the precise GMT (from the chronometer/watch with its error). The time fixes the body's GHA and declination from the Almanac; the altitude (corrected to Ho) gives the LOP.
Authority: Bowditch (Pub. No. 9), Sight Taking
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