The Nautical Almanac and Astronomical Ephemeris for the Year ...order of the Lords Commissioners of the Admiralty, 1845 |
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Common terms and phrases
Aldebaran W Antares W Apparent Declination Apparent Right Ascension Aquarii Aquila Aquila E Arietis Aldebaran Arietis E ASCENSION AND DECLINATION Cancri Capricorni Ceti d h m Declination diameter diff Earth EPHEMERIS Fomalhaut Fomalhaut E Frid FRIDAY Geminor Geocentric Greenwich Mean Greenwich Transit Heliocentric Hour of Long Hour of pass inverting telescope Jupiter Regulus Spica Jupiter W Leonis Libræ Logarithm LUNAR DISTANCES Mars Pollux Mean Noon Meridian Longitude Meridian of Greenwich MONDAY Month Moon I. L. Moon II MOON'S RIGHT ASCENSION Name and Position OCCULTATIONS Ophiuchi Passage Pegasi E Pegasi Saturn Pollux W R. A. Dec Regulus W Right Asc Sagittarii SATELLITES OF JUPITER SATURDAY Saturn a Arietis Saturn E Semi Semidiam Shadow Spica mg Spica ng Antares Star's Name SUN E.
E. SUNDAY Tauri Thur THURSDAY True Dist Tues TUESDAY Variation of Right Vect Venus SUN Virginis WEDNESDAY
Popular passages
Page 615 - The progressive motion of light, combined with the motion of the Earth in its orbit...
Page 564 - Year 1881 there will be two Eclipses of the Sun and two of the Moon, and a transit of Mercury across the Sun's disc.
Page 606 - Moon is respectively at her greatest and least distance from the Earth. Pages XIII. to XVIII. of each Month. Lunar Distances. — These pages contain, for every third hour of Greenwich mean time, the angular distances between the apparent centres of the Moon and certain heavenly bodies, such as they would appear to an observer at the centre of the Earth. When a Lunar Distance has been observed on the surface of the Earth, and reduced to the centre, by clearing it of the effects of parallax and refraction,...
Page 598 - It may therefore be called the mean astronomical day, although, in practice, astronomers begin the day at the moment the true Sun's centre is on their meridian. In the civil, or common, method of reckoning, the day is supposed to commence at the preceding midnight...
Page 606 - PL of diff." contain the proportional logarithms of the differences of the distances at intervals of three hours, which are used in finding the Greenwich time corresponding to a given distance, according to the following rule, viz. : For the given day, seek in the Ephemeris for the nearest distance preceding, in order of time, the given distance, and take the difference between it and the given distance ; from the proportional logarithm of this difference subtract the proportional logarithm...
Page 174 - THE SATELLITES OF JUPITER are not visible this Month, JUPITER being too near to the SUN.
Page 606 - ... in the Ephemeris ; the remainder will be the proportional logarithm of a portion of time to be added to the hour answering to the nearest preceding distance, to obtain the approximate Greenwich mean time corresponding to the given distance.
Page 618 - Ascension indicates that the variation ig to be added to, and the sign —, that it is to be subtracted from, the Right Ascension : also, for Stars having North Declination, + signifies add, and — subtract : but for Stars of South Declination, + denotes that the Variation is to be subtracted from, and — that it is to be added to, the Declination. Example 1.
Page 615 - Aberration, or the quantity to be applied to the true longitude of the Sun to obtain the apparent longitude. The longitudes derived from the Solar Tables include Aberration, and are therefore apparent longitudes, such as are contained in this Ephemeris. If the true longitude of the Sun be wanted, as is the case in finding the longitude of the Earth for the calculation of the Geocentric place of a body, the aberration must be applied with a contrary sign. Thus, on June 10, 1844, at Mean Noon, by adding...
Page 614 - Parallax is the greatest angle under which the equatorial scmidiameter of the earth would appear at the Sun's centre. It varies inversely as the distance, and the numbers in this column show the values for every tenth day of the year. The Parallax serves for reducing a solar observation made at the surface of the earth to what it would have been if made at...