. A new treatise on the practice of navigation at sea : containing all the details necessary to enable the mariner to become a good practical navigator. . In this Figure th* Sun in on the Prime Vertical, to the Westward of the Meridian, and his Hour Anglemeasured on the Equator gives the Apparent Time of the , 2h 58m P. M. The Moon havingnearly the same Hour Angle to the Eastward of the Meridian, appears to a spectator situated at a greatJistauoe to the Eastward of the Earth, (which is in the centre,) to be nearly in the same line of bearing^jut the following Figure, drawn with the
. A new treatise on the practice of navigation at sea : containing all the details necessary to enable the mariner to become a good practical navigator. . In this Figure th* Sun in on the Prime Vertical, to the Westward of the Meridian, and his Hour Anglemeasured on the Equator gives the Apparent Time of the , 2h 58m P. M. The Moon havingnearly the same Hour Angle to the Eastward of the Meridian, appears to a spectator situated at a greatJistauoe to the Eastward of the Earth, (which is in the centre,) to be nearly in the same line of bearing^jut the following Figure, drawn with the objects facing the spectator, will place them in a better point ofTiew for showing the nature of the case. DIAGRAM OF A LUNAR,Drawn on the Plane of the Prime Vertical. 0 Fig. 30. 7tNITH tp L OlST ; 8 7^3^ 12. ISAeci-lA THOKISSCHY. In this last Figure both bodies are seen on the Prime Vertical, East and West of the Meridian, theirAltitudes are laid off from the line of Chords, and their Apparent Central Distance measures on the scale88* 13 29. Now, it is evident that by raising the Moon (which the correction for Parallax does) wobring the Moon nearer the Sun, while the correction for Refraction the Distance by lowering thebodies; but as the former has more effect than the latter, the Moons True Distance, according to theFigure, is less than the Apparent Central Distance. This quantity is found by the Rules given on th©oext page, and which is termed Clearing the Lunar Distance. * This Correction is simply the Difference between the Semidlameters taken at 16, and the Pip of the Horizon, take»»t 4, to be added when the Lower Limbs are taken. LUNAR OBSERVATION. lAf TO FIND THE APPARENT ALTITUDES AND DISTANCE. Turn the LongHude by Dead Reckoning into time by Table XXVI, and aaa if
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnavigat, bookyear1902
