Celestial Navigation · Coordinates
How is the GHA of a star obtained from the Nautical Almanac?
- AGHA star = GHA Aries minus the star's declination
- BGHA star = GHA Aries plus the star's SHA✓ Correct
- CGHA star = SHA minus GHA Aries
- DGHA star is tabulated directly for each hour like the Sun
Explanation
Stars are located relative to the First Point of Aries. GHA star = GHA Aries + SHA (sidereal hour angle) of the star. The Almanac tabulates GHA Aries hourly and lists each star's SHA, which changes only slowly.
Authority: Nautical Almanac
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