Principles of Celestial Navigation

A Day in the Life of a Navigator » Overview of a Day in the Life of a Navy Navigator

U.S. Navy photo of seas at sea with Sun shining through clouds

To demonstrate the celestial navigation techniques used in the U.S. Navy, we will go through many of the major duties used to determine a ship’s position throughout a typical day. Each of the following duties will be described in more detail later in the module.

We will demonstrate five procedures used during a typical day:

  1. We begin with a known position shortly after midnight. From that, we make a DR plot until we obtain a three-star fix in morning twilight.
  2. We take a Sun line a few hours after sunrise, then a Local Apparent Noon Sun line at noon.
  3. We obtain an estimated position at noon.
  4. A few hours later, we take another Sun line. This will be combined with the morning and noon Sun lines to obtain a running fix.
  5. Finally, we obtain another three star fix in evening twilight.

For our “Day in the Life of a Navy Navigator”, we will use the date 17 July, 2018, although any date could be chosen. Time will be given in Universal Time, often called Greenwich Mean Time.