Celestial Navigation · Meridian Altitude — LAN Timing
Local apparent noon (LAN) occurs at the moment the sun:
- ASets below the horizon
- BRises above the horizon
- CReaches an azimuth of due east
- DCrosses the observer's meridian and reaches its maximum altitude for the day✓ Correct
Explanation
At LAN the sun transits the observer's meridian (bearing due north or due south) and attains its greatest altitude of the day. The meridian altitude gives latitude directly, and the time of LAN can be used to find longitude.
Authority: Bowditch (Pub. No. 9), The Day's Work
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