The Elements of Astronomy: Or, The World as it Is, and as it AppearsCrocker and Brewster, 1850 - 376 σελίδες |
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Σελίδα 13
... equal ; all the diameters are also equal , and double the radius . § 2. Every section of a sphere made by a plane is a circle . If a sphere is cut by a plane which passes through the centre , the section is called a great circle of the ...
... equal ; all the diameters are also equal , and double the radius . § 2. Every section of a sphere made by a plane is a circle . If a sphere is cut by a plane which passes through the centre , the section is called a great circle of the ...
Σελίδα 15
... equal to a semi circumference . to- A great circle is equally distant from its two poles ; but this is not the case with a small circle . Equal circles of the sphere have equal polar distances , and conversely . The polar distances of ...
... equal to a semi circumference . to- A great circle is equally distant from its two poles ; but this is not the case with a small circle . Equal circles of the sphere have equal polar distances , and conversely . The polar distances of ...
Σελίδα 17
... equal and parallel small circles , it will cut the other likewise . § 9. In order to compare together different arcs and angles , every circumference of a circle is supposed to be divided into 360 equal arcs , called degrees , and ...
... equal and parallel small circles , it will cut the other likewise . § 9. In order to compare together different arcs and angles , every circumference of a circle is supposed to be divided into 360 equal arcs , called degrees , and ...
Σελίδα 21
... equal all over the world . § 22. The ecliptic is divided into twelve equal parts called signs : -Aries , Taurus , Gemini , Cancer , Leo , Virgo , Libra , Scorpio , Sagittarius , Capricornus , Aquarius , Pisces . The order of these is ...
... equal all over the world . § 22. The ecliptic is divided into twelve equal parts called signs : -Aries , Taurus , Gemini , Cancer , Leo , Virgo , Libra , Scorpio , Sagittarius , Capricornus , Aquarius , Pisces . The order of these is ...
Σελίδα 22
... equal to the distances of the tropics from the equator . These are also called the polar circles . § 25. The altitude of the elevated pole being equal to the spectator's geographical latitude , it follows that all the stars whose polar ...
... equal to the distances of the tropics from the equator . These are also called the polar circles . § 25. The altitude of the elevated pole being equal to the spectator's geographical latitude , it follows that all the stars whose polar ...
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The Elements of Astronomy, Or the World as It Is, and as It Appears (Classic ... Anna Cabot Lowell Δεν υπάρχει διαθέσιμη προεπισκόπηση - 2016 |
The Elements of Astronomy, Or, the World as it Is, and as it Appears Δεν υπάρχει διαθέσιμη προεπισκόπηση - 2020 |
Συχνά εμφανιζόμενοι όροι και φράσεις
altitude angular aphelion appear ascertained astronomical atmosphere attraction axis body called cause celestial centre of gravity centrifugal force circle cluster comet constellations curve density described diameter direction disc distance disturbing earth earth's surface eccentricity ecliptic equal equator equatorial equinoctial feet fixed stars globe greater heat heavens hemisphere Herschel horizon illuminated inclined increase inequalities John Herschel Jupiter Jupiter's latitude length less light longitude lunar mass measure meridian miles minute moon moon's move nearer nearly nebulous nodes nucleus nutation obliquely observed parallax parallel passes perigee perihelion period perpendicular planets polar pole portion position proper motion proportion radius rays refraction revolution revolve right angles right ascension rise rotation satellites Saturn seen shadow side sidereal sidereal day solar system space sphere sun's suppose tail telescope tion Uranus vapor variations velocity Venus vernal equinox vertical visible whole zenith zodiacal light
Δημοφιλή αποσπάσματα
Σελίδα 330 - ... that the mean longitude of the first satellite, minus three times that of the second, plus twice that of the third, is always equal to two right angles.
Σελίδα 262 - But, in the midst of all these vicissitudes, the length of the major axes and the mean motions of the planets remain permanently independent of secular changes. They are so connected by Kepler's law, of the squares of the periodic times being proportional to the cubes of the mean distances of the planets from the sun, that one cannot vary without affecting the other.
Σελίδα 37 - Now, suppose the head of the screw to be a circle, whose diameter is an inch, the circumference of the head will be something more than three inches : this may be easily divided into a hundred equal parts distinctly visible. If a fixed index be presented to this graduated circumference, the hundredth part of a revolution of the screw may be observed, by noting the passage of one division of the head under the index. Since one entire revolution of the head moves the point through the fiftieth of an...
Σελίδα 199 - our astronomical observer" at a salary of £100 per annum, his duty being "forthwith to apply himself with the most exact care and diligence to the rectifying the tables of the motions of the heavens and the places of the fixed stars, so as to find out the so much desired longitude of places for the perfecting the art of navigation.
Σελίδα 22 - The Latitude of a star is its angular distance from the ecliptic measured on a circle of latitude.
Σελίδα 13 - A sphere is a solid terminated by a curved surface all the points of which are equally distant from a point within called the centre.
Σελίδα 258 - The radial force, or that part of the disturbing force which acts in the direction of the line joining the centres of the sun and disturbed planet, has no effect on the areas, but is the cause of periodical changes of small extent in the distance of the planet from the sun. It has already been shown, that the force producing perfectly elliptical motion varies inversely as the square of the distance, and...
Σελίδα 13 - The radius of a sphere, is a straight line drawn from the center to any point of the surface.
Σελίδα 38 - Now, the arc of a circle, subtended by one second, is less than the 200,000th part of the radius, so that on a circle of 6 feet in diameter it would occupy no greater linear extent than part of an inch ; a quantity requiring a powerful microscope to be discerned at all.
Σελίδα 345 - As the moon can never be full but when she is opposite to the sun, and the sun is never in Virgo and Libra, but in our autumnal months, it is plain that the moon is never full in the opposite signs, Pisces and Aries, but in these two months. And...