## An Epitome of Navigation and Nautical Astronomy with the Improved Lunar Tables1842 - Nautical astronomy - 546 pages |

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### Common terms and phrases

Altitudes and Horizontal angle Apparent Altitude APPARENT DISTANCE Argo Navis azimuth called Cape celestial centre chronometer circle Co-secant Co-sine Co-tang co.ar compass constellations correction corresponding decimal Degrees diameter difference of latitude difference of longitude Dist Dep Dist Lat distance run draw earth east eclipse ecliptic equal equator Examples for Exercise find the Course find the difference fixed star given Greenwich Greenwich mean H.Ang height index error island latitude and longitude Logarithmic Sines Long mean meridian altitude miles minutes moon Moon's Horizontal Parallax motion Nautical Almanac noon observed altitude orbit Parallel Sailing perp Plane Sailing planet polar distance PROPORTIONAL LOGARITHMS refraction remainder right ascension Secant semidiameter sextant ship from latitude Star's sub sub subtract Sun or Star sun's declination sun's lower limb Sun's true Tangent Traverse Table triangle true altitude true distance variation zenith

### Popular passages

Page 4 - An improper fraction is one in which the numerator is equal to or greater than the denominator, such as ^ , ^ , or ^ . 4.

Page 169 - To find the logarithm of a number consisting of more than four figures; Take out the logarithm of two numbers, one greater, and the other less, than the number proposed : Find the differ'ence of the two numbers, and the difference of their logarithms : Take also the difference between the least of the two numbers, and the proposed number. Then say, As the difference of...

Page 4 - The number under the line is called the denominator, because it gives name to the fraction ; and the number above the line is called the numerator, because it shows the number of parts used. Thus T\, 10 is the denominator and 3 the numerator.

Page 71 - The earth revolves on its axis in about twentyfour hours : if the moon were stationary, therefore, the same part of our globe would, every twentyfour hours, return beneath the moon ; but as during our daily revolution the moon advances in her orbit, the earth must make more than a complete rotation in order to bring the same meridian opposite the moon : we are three-quarters of an hour in overtaking her.

Page 23 - If a straight line be drawn parallel to one of the sides of a triangle, it shall cut the other sides, or those sides produced, proportionally; and if the sides, or the sides produced, be cut proportionally, the straight '.line which joint the points of section, shall be parallel to the remaining side of the triangle.

Page 6 - RULE. Divide as in whole numbers, and from the right hand of the quotient point off as many places for decimals as the decimal places in the dividend exceed those in the divisor.

Page 50 - The latitudes of places are reckoned from the equator northward and southward, and the longitudes are reckoned upon it eastward and westward. The equator, when referred to the heavens, is called the equinoctial, because, when the sun appears in it, the days and nights are equal all over the world, viz., 12 hours each. The...

Page 51 - ... upon which the rays of the sun fall vertically at the two solstices. These limits, at which the sun appears to stop and then return in the same course, have received the name of tropics.

Page 175 - Then with the latitude and declination, find in the table, the time the star takes in ascending from the horizon to the meridian, and descending from the meridian to the horizon, when the latitude and the declination are of the same name.

Page 6 - The log-line is divided into equal portions, called knots, at each of which a bit of string, with the number of knots upon it, is put through the strands. The length of a knot depends on the number of seconds which the glasses measure, and is thus determined : The No.