## Navigation and Nautical Astronomy, Part 1Longman, Brown, Green, and Longmans, 1858 |

### From inside the book

Results 1-5 of 50

Page v

... mean time 988 86 87 888 88 90 91 92 XXI . Given hour angle to find

... mean time 988 86 87 888 88 90 91 92 XXI . Given hour angle to find

**ship mean**time 28865 95 98 XXII . To find at what time any heavenly body will pass the meridian 100 Parallax 102 Augmentation of the moon's semidiameter Refraction ... Page vi

...

...

**mean**time at the**ship**by a single altitude of the sun 161 166 168 • 170 XLIV . To find the error of chronometer on**mean**time at Greenwich by a single altitude of the sun 172 XLV . To find error of chronometer on**mean**time by single ... Page 71

...

...

**Ship**times . ( 21 ) Mar. 7 , at 3h 15m A.M. Long . 15 ° 45 ′ E. Answers , Greenwich dates . Mar. 6 , at 14h 12m Mar ...**mean**time is known . Rule VI . To the time shown by chronometer , apply its error on Greenwich**mean**time ... Page 74

... means of a figure . Let Ax be the celestial equator , A o the ecliptic , s , and s mu m R1R RI the places of the ...

... means of a figure . Let Ax be the celestial equator , A o the ecliptic , s , and s mu m R1R RI the places of the ...

**ship mean**time expressed astronomically . 2. Under which put the longitude in time . 3. Add in west , subtract in ... Page 90

...

...

**mean**sun by the table ( p . 83 ) , or by proportional logarithms , or otherwise for the Greenwich date . 3. Add together the corrected right ascension of**mean**sun and**mean**time at the**ship**. 4. The sum ( rejecting 24 hours if greater ...### Other editions - View all

### Common terms and phrases

24 hours altitude for index apparent distance April 27 ascension mean sun ascension of mean auxiliary angle celestial concave celestial equator chro colatitude compass bearing correction in altitude cosec decl diff east of meridian Elements from Nautical EXAMPLES find the latitude Greenwich date Greenwich mean haversines heavenly body height of eye horizontal parallax hour angle Index cor index correction June longitude by chronometer mean time nearly moon moon's declination Moon's right Moon's semi moon's semidiameter Nautical Almanac observed altitude observed meridian altitude P.M. mean pass the meridian point of Aries polar distance pole proportional logarithm refraction required the latitude required the longitude required the true Right asc Right ascension mean sea 20 feet ship mean sidereal star subtract Sun's declination sun's L. L. sun's lower limb true altitude true bearing true distance true zenith distance vers versines zenith dist

### Popular passages

Page 12 - Fig. 3) loaded on the circular side with lead sufficient to make it swim upright in the water: to this is fastened a line about 150 fathoms long, called the Log-line, which is divided into certain spaces called knots, and is wound on a reel (see Plate VI.

Page 54 - ... consequence of the whirling motion of the earth about its axis, the parts near the equator, which have the greatest velocity, acquire thereby a greater distance from the centre than the parts near the poles.

Page 60 - The hour angle of a heavenly body, is the angle at the pole between the celestial meridian and the circle of declination passing through the place of the body ; thus, zpx is the hour angle of x.

Page 59 - The right ascension of a heavenly body is the arc of the equator, intercepted between the first point of Aries and the circle of declination, passing through the place of the...

Page 61 - The apparent solar day is the interval between two successive transits of the sun's centre over the same meridian.

Page 63 - Mean Solar Day is the interval between two successive transits of the mean sun over the same meridian ; it begins when the mean sun is on the meridian.

Page 13 - ... ascertained at sea by observing the magnetic bearing of- the sun when in the horizon, or at a given altitude abo-ve it. From this observation the true bearing is found by rules given in nautical astronomy. The difference between the true bearing and the observed bearing by compass determines this correction.

Page 258 - W., and at the same time the observed altitude of the sun's lower limb was 21° 40' 45", the index correction was — 2' 18", and the height of the eye above the sea was 14 feet : required the variation.

Page 199 - To the hour angle thus found, add the star's right ascension; and from the sum, increased if necessary by 24 hours, subtract the right ascension of the mean sun ; the remainder is mean time at the place at the instant of observation.

Page 54 - ... path of the sun as seen from the Earth, and is called the Ecliptic. The plane of the Earth's equator, extended till it meets the concave surface of the heavens, forms what is called the Celestial Equator, or the Equinoctial. The ecliptic and the equinoctial form an angle of 23° 28', and this angle is called the Obliquity of the Ecliptic. The axis of the Earth, therefore, instead of being perpendicular to the plane of its orbit, is inclined to it at an angle of (90° — 23° 28') 66° 32'.