The Hydrographer of the SA Navy is responsible for producing a table of tides covering the South African coast and that of Namibia. These tables contain: The predicted times and heights of low water and high water in all South African and Namibian ports, as well as the phases of…
Tides can be defined as the periodic rise and fall of the level of the sea caused by the combined solar and lunar gravitational forces acting on the earth. There are generally two high waters and two low waters occurring at any place during a period of 24 hours and…
The procedure laid out below should be followed to find the latitude of the observer at meridian passage. A pro forma format for working the problem out is also provided and should be followed in conjunction with the procedure. A good navigator will start preparing for the midday sight an…
When the sun and the observer’s zenith are on the same celestial meridian, then there is a simple relationship between declination, zenith distance and the latitude. All three are arcs of the same great circle and their values give the distance of each point from the celestial equator (equinoctial) and…
The local mean time (LMT) of mer pass on any meridian is obtained from the Nautical Almanac. At the bottom of the right hand page of the three-daily tables is a small table entitled “sun-mer pass”. The time of mer pass for the three days covered by the page is…
Introduction Meridian passage of an observed heavenly body, ie the sun, occurs when the body is directly over the observer’s meridian and the local hour angle (LHA) is zero. During this course we will only be covering the meridian passage (mer pass) of the sun. Those who wish to become…
