Celestial Navigation · Hour Angle
Meridian angle (t) differs from Local Hour Angle (LHA) in that meridian angle is:
- AAlways measured eastward only
- BIdentical to declination
- CMeasured 0°–180° east or west of the meridian, rather than 0°–360° westward✓ Correct
- DMeasured from the First Point of Aries
Explanation
LHA is measured westward from 0° to 360°. Meridian angle t is the same arc expressed 0°–180° and labeled east or west, which is the form used in some sight-reduction methods and the time-sight formula.
Authority: Bowditch (Pub. No. 9)
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