Principles of Celestial Navigation

The Intercept Method » Computed Altitude and Azimuth (Hc and Zn) » Determining Hc and Zn by Hand

Although not necessary for learning the fundamentals of how celestial navigation works, in order for celestial navigation to be a true emergency navigation system, navigators should know how to determine Hc and Zn without the use of electronics. Strip forms will lead us through the steps, and special publications such as The Nautical Almanac and "Publication No. 229, Sight Reduction Tables for Marine Navigation" are published so complex math is unnecessary.

photo of Pub 229 and The Nautical Almanac

For more on determining Hc and Zn by hand, see the Supplemental Material section.

Now that we’ve determined the computed altitude (Hc) and the azimuth (Zn), we’ll continue through the intercept method and watch and listen as Chief Sheedy leads us through plotting the line of position.