— Certification
The US Coast Guard requires celestial navigation competency for Mate and Master licenses on ocean routes (above 200 gross tons). Candidates are tested on sight reduction using HO 229 tables.
The USCG celestial navigation exam is a standalone module covering sun, star, and planet sight reduction, as well as compass error by celestial observation.
HO 229
Sailcasted simulates realistic ocean passages. Every day, you receive an astronomical observation by email — just like at sea. You reduce it with your tables (HO 229), calculate your position, and submit your fix. The platform calculates your error in nautical miles.
Observations are generated from USNO/JPL ephemerides with ±0.5 arcminute accuracy — the same precision as official nautical almanacs.
Sailcasted passages are organized into 4 tiers of increasing difficulty. Start at Tier 1 with simple observations (sun only) and progress to Tier 4 with complex observations (stars, planets, challenging conditions).
To prepare for your USCG exam, you will need:
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