Grade 12 – Nautical Science

September 4, 2020

Alternative method of obtaining the sun’s azimuth.

In sub-paragraphs h to k of the procedure, the true bearing is obtained through the use of the A, B, C tables in Nories. There is an alternative method of determining true bearing, namely by calculation. There are two formulas that could be used: Sine formula. In order to convert […]
September 5, 2020

Astro running fixes

When using the observation of heavenly bodies to determine geographical position, a “day’s work” for a navigator comprises five sets of astro sights (provided the weather is cooperative): During morning nautical twilight the navigator will take the sextant altitudes of at least three or four heavenly bodies and using this […]
September 7, 2020

The azimuth

In order to determine the error of the gyro or magnetic compass by astronomical observation, one must be able to find the true bearing of a celestial body from the observer at any time. By comparing the compass bearing with the bearing calculated at a specific time, one can determine […]
September 7, 2020

The amplitude

An amplitude is the “azimuth” of a heavenly body when it is on the observer’s rational horizon. The angle at the zenith between the prime vertical circle (the vertical circle passing through the east and west points) and the vertical circle passing through the body is called the amplitude of […]
September 7, 2020


Introduction Radar is an acronym derived from RAdio Detection And Ranging. It is an electronic detection system making use of super high frequency radio signals which are reflected off objects in their path. By utilising specially designed antennas and control equipment, it is possible to obtain reasonably accurate bearings of […]