Celestial Navigation · Assumed Position
When reducing a sight with Pub. 229 or 249, how is the assumed longitude chosen?
- ASo that the assumed latitude is a whole degree
- BAlways to the nearest 5° of longitude
- CEqual to the DR longitude exactly
- DSo that LHA comes out to a whole degree (assumed longitude near the DR, with the same minutes as GHA)✓ Correct
Explanation
The sight reduction tables are entered with whole-degree arguments. Assumed latitude is the whole degree nearest the DR; assumed longitude is chosen near the DR so that combining it with GHA yields a whole-degree LHA.
Authority: Pub. No. 229 / Pub. No. 249 sight reduction; Bowditch (Pub. No. 9)
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