Celestial Navigation · Fix — Crossing Sun and Moon
A daytime celestial fix can sometimes be obtained by:
- ACrossing a sun line with a simultaneous moon (or Venus) line when both are visible by day✓ Correct
- BTaking two sun lines at the same instant
- CObserving stars at noon
- DUsing the chronometer alone
Explanation
When the moon (or bright Venus) is above the horizon in daylight along with the sun, their two LOPs taken close together can be crossed for a daytime fix — a useful alternative to a sun-run-sun running fix when a second body is available.
Authority: Bowditch (Pub. No. 9), The Day's Work
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