A New System of Practical Astronomy: Made Plain and Easy to Those who Have Not Studied Mathematics : Containing the Elementary Principles of the Science, All the Rules and Tables Necessary for Making All the Calculations for an Almanac ... |
From inside the book
Results 1-5 of 38
Page 9
... sun's distance from the node is used instead of the moon's ; because the sun's place is much easier to find than the ... mean , or average distance of the sun from the earth , is 95 millions of miles , but at the nearest point of the orbit , ...
... sun's distance from the node is used instead of the moon's ; because the sun's place is much easier to find than the ... mean , or average distance of the sun from the earth , is 95 millions of miles , but at the nearest point of the orbit , ...
Page 10
... sun's and moon's motion to become slower . The distance of the sun or moon from its apogee , perigee , or any other ... mean ; the unequal are justly called the true . The mean place of the sun or moon is always before the true place ...
... sun's and moon's motion to become slower . The distance of the sun or moon from its apogee , perigee , or any other ... mean ; the unequal are justly called the true . The mean place of the sun or moon is always before the true place ...
Page 11
... sun and moon were always uniform and equal in one part of their orbit to what they were in any other part . But this is not the case ; and the strong attraction of the earth and sun upon the moon varies her motion , and makes the above mean ...
... sun and moon were always uniform and equal in one part of their orbit to what they were in any other part . But this is not the case ; and the strong attraction of the earth and sun upon the moon varies her motion , and makes the above mean ...
Page 12
... sun and moon , is the reason their mean and trus aces differ : for the same reason , the time of mean syzygy differs from the time of true syzygy . The first difference , or equation , between the mean and true syzygy , is caused by the ...
... sun and moon , is the reason their mean and trus aces differ : for the same reason , the time of mean syzygy differs from the time of true syzygy . The first difference , or equation , between the mean and true syzygy , is caused by the ...
Page 13
... sun's mean anomaly , used to reduce the sun's mean place to the true place . The principle has already been explained . Table 12 , page 15 , is on the same principle as Table 11. It is formed by adding the annual equation of the Moon's ...
... sun's mean anomaly , used to reduce the sun's mean place to the true place . The principle has already been explained . Table 12 , page 15 , is on the same principle as Table 11. It is formed by adding the annual equation of the Moon's ...
Common terms and phrases
altitude angle aphelion apogee appear argument astronomers cask centre circle diameter difference diurnal motion divide dominical letter draw ecliptic Epact equal equator equinox fixed star Frustum Full Moon given side heavenly bodies heavens horizon Horizontal Parallax Hourly Motion inferior planets Jupiter Leap leap-year length less logarithm longitude and anomaly lunation mean longitude mean motion Mean New Moon meridian miles minutes month Moon's Ascending Node moon's mean anomaly moon's orbit moves round nearest noon number of days number of degrees numbers for March opposite Parallax perigee perpendicular point of aries pole PROB quotient radius remainder revolve round right ascension right line round the earth round the sun RULE Saturn secant seen Semidiameter Semidiurnal arc signs sine solar station subtract sun and moon sun's declination sun's mean anomaly sun's place Table tangent triangle true Longitude true syzygy Venus vernal equinox
Popular passages
Page 33 - No objection, says he, ariseth to that great luminary being inhabited ; vegetation may obtain there, as well as with us. There may be water and dry land, hills and dales, rain and fair weather, and as the light, so the season, must be eternal, consequently it may easily be conceived to be by far the most blissful habitation of the whole system.
Page 9 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.
Page 36 - ... below, seem to bid defiance to the laws of gravitation. Around the base of these frightful eminences, are strewed numerous loose and unconnected fragments, which time seems to have detached from their parent mass ; and when we examine the rents and ravines which accompany the over-hanging cliffs, we expect every moment that they are to be torn from their base, and that the process of destructive separation which we had only contemplated in its effects, is about to be exhibited before us in tremendous...
Page 40 - ... escape all observation, by reason of their paths traversing only that part of the heavens which is above the horizon in the daytime. Comets so circumstanced can only become visible by the rare coincidence of a total eclipse of the sun, a coincidence which happened, as related by Seneca, 60 years before Christ, when a large comet was actually observed very near the sun.
Page 4 - Instead, then, of one sun, and one world only in the universe, as the unskilful in astronomy imagine, that science discovers to us, such an inconceivable number of suns, systems, and worlds, dispersed through boundless space, that if our sun, with all the planets, moons, and comets, belonging to it, were annihilated, they would be no more missed by an eye that could take in the whole creation, than a grain of sand from the seashore ; the space they possess being comparatively so small, that it would...
Page 31 - ... but are variously affected by the action of the sun, which brings them on sooner, when the moon is in her first and third quarters ; and keeps them back later, when she is in her second and fourth. Because in the former case the tide raised by the sun .alone would be earlier than the tide raised...
Page 40 - ... must be at least many thousands. Multitudes, indeed, must escape all observation, by reason of their paths traversing only that part of the heavens which is above the horizon in the day-time.
Page 70 - The tropics are two small circles parallel to the equator at the distance of 23° 28' from it ; the northern, is called the tropic of cancer, and the southern, the tropic of Capricorn.
Page 36 - The climate of the moon must be very extraordinary : the alternation being that of unmitigated and burning sunshine, fiercer than an equatorial noon, continued for a whole fortnight, and the keenest severity of frost, far exceeding that of our polar winters, for an equal time.
Page 3 - that Copernicus, seized with a daring enthusiasm, laid his hands on the cycles and crystal orbs of Ptolemy, and dashed them to pieces. And that with the same noble phrenzy, he took the unwieldy earth, and sent her far from" the centre of the system, to move round the sun with the rest of the planets.