MMA Assessment OICNW-1-1C

Aboard a ship at sea, given a standard marine sextant, a clear horizon, a clear or partly cloudy sky, and an accurate time, during a single twilight.

Behavior	Standard
The student will:	During assessment, the student shall, at a minimum:
Measure the altitude of three stars and accurately record the times of the observation of each star.	Determine altitudes within ± 2 minutes of arc, after correction for index error, as compared with the altitude measured by the assessor at the same time; Record an observation time which is within ± 2 seconds of UTC of the time of observation as determined by the assessor.
Plot three lines of position and advance them to a common time.	Plot the resultant position of the star fix within 1.5 nm of the ship’s GPS position at the corresponding time, or within 3 nm of the assessor’s solution taken during the same time.

Obtain a celestial fix