ASA 107 -
Celstial Navigation Standard

Prerequisite: None

General Description: Able to demonstrate the Celestial Navigation theory required to safely navigate a sailboat on an offshore passage. The practical application is conducted in the Offshore Passagemaking Standard.
A Certified Sailor has successfully demonstrated his or her ability to:

• Convert longitude into time.
• Convert standard time and zone time to GMT and vice versa.
• Calculate the zone time given longitude.
• Calculate the chronometer (or watch) error given a previous error and the daily rate.
• Apply the corrections for index error, dip of the horizon, and total correction to convert sextant altitudes of the sun, stars, planets, and moon to true altitudes.
• Calculate the time of meridian passage of the sun and calculate the boat's latitude from the observed meridian altitude of the sun.
• Determine the latitude at twilight by means of the Pole Star.
• Solve the navigational triangle using a navigation table and show all appropriate work.,
• Plot celestial lines of position on a Mercator projection or on a universal plotting sheet
• Calculate the times (ship's and GMT) of sunrise, sunset and twilight.
• Determine the approximate azimuths and altitudes of the navigational stars and planets at twilight.
• Calculate and plot the lines of position obtained from observations of several celestial bodies at twilight and thus find the boat's position.
• Advance the LOP obtained from a sun sight to another LOP obtained from the sun at a later time and find the boat's position using a running fix (sun-run-sun).
• Calculate the true bearing of a low altitude celestial body in order to determine the error and deviation of the compass.

.