The Elements of Astronomy: For Colleges, Schools, and Private Students : Written for the Mathematical Course of Joseph RayWilson, Hinkle & Company, 1869 - 336 páginas |
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Página 38
... great dif- ficulty of casting glass in large masses suitable for as- tronomical purposes . A lens of 25 inches aperture has lately been made in England . Fig . 24 . ANGLE OF INCIDENCE ANGLE OF REFLECTION 38 ELEMENTS OF ASTRONOMY .
... great dif- ficulty of casting glass in large masses suitable for as- tronomical purposes . A lens of 25 inches aperture has lately been made in England . Fig . 24 . ANGLE OF INCIDENCE ANGLE OF REFLECTION 38 ELEMENTS OF ASTRONOMY .
Página 39
... REFLECTION REFLECTION . 72. A ray of light which meets a plane mirror is turned back , or re- flected , and passes ... Reflected image . - At a cer- tain distance , all the rays of light which come from one point of the object viewed ...
... REFLECTION REFLECTION . 72. A ray of light which meets a plane mirror is turned back , or re- flected , and passes ... Reflected image . - At a cer- tain distance , all the rays of light which come from one point of the object viewed ...
Página 41
... reflected the rays a second time and turned Fig . 28 . them into an eye - piece in the side of the tube . Gregory used a small concave mirror which returned the rays Fig . 29 . through a small hole at the center of the speculum ...
... reflected the rays a second time and turned Fig . 28 . them into an eye - piece in the side of the tube . Gregory used a small concave mirror which returned the rays Fig . 29 . through a small hole at the center of the speculum ...
Página 47
... reflected from the mercury . The lines from the distant star , SD and S'O , are parallel , and make equal angles with horizontal lines through D and O ( Geom . 138 ) ; the lines S'O and OD make angles of incidence and reflection at O ...
... reflected from the mercury . The lines from the distant star , SD and S'O , are parallel , and make equal angles with horizontal lines through D and O ( Geom . 138 ) ; the lines S'O and OD make angles of incidence and reflection at O ...
Página 60
... reflected from the mirror I , appears in the mirror F exactly under the star . The angle between the moon and the star is shown by the part of the scale which is traversed by the index ( App . II ) . At D and E are several colored ...
... reflected from the mirror I , appears in the mirror F exactly under the star . The angle between the moon and the star is shown by the part of the scale which is traversed by the index ( App . II ) . At D and E are several colored ...
Términos y frases comunes
2d mag Alpha Centauri altitude angle appears Arcturus astronomical attraction axis body bright stars brightest called Capricornus cause celestial clock comet conjunction constellation culmination curve daily motion dark declination density diameter distance earth earth's orbit east eccentricity ecliptic equal equator equatorial equinoctial farther fixed stars heat Hence Herschel horizon Jupiter latitude length libration light longitude lunar lunar eclipses Mars mass mean solar measured Mercury meridian meteors millions of miles moon moon's move nearly nebula node observer Ophiuchus opposite parallax particles passes path penumbra perihelion photosphere planet polariscope pole position prime vertical radius rays refraction revolution revolve right ascension ring rotation satellites Saturn seen shadow shows side sidereal sidereal day solar day solar eclipse solar system solstice space spots supposed surface tail telescope tide tion transit triangle Uranus velocity Venus vernal equinox vertical visible zenith
Pasajes populares
Página 143 - The MASS of a body is the quantity of matter which it contains.
Página 237 - Uranus a full-sized cherry, or small plum, upon the circumference of a circle more than a mile and a half in diameter. As to getting correct notions on this subject by drawing circles on paper, or, still worse, from those very childish toys called orreries, it is out of the question.
Página 237 - Mercury will be represented by a grain of mustard seed, on the circumference of a circle 1 64 feet in diameter for its orbit; Venus a pea, on a circle 284 feet in diameter ; the Earth also a pea, on a circle of 430 feet; Mars a rather large pin's head, on a circle of 654 feet...
Página 126 - Hath left to their disputes, perhaps to move His laughter at their quaint opinions wide Hereafter ; when they come to model Heaven And calculate the stars, how they will wield The mighty frame ; how build, unbuild, contrive To save appearances ; how gird the sphere With centric and eccentric scribbled o'er, Cycle and epicycle, orb in orb...
Página 208 - ... she is in the meridian of that place ; and that the sun performs a secondary part in their production may be proved from the circumstance, that the highest tides take place when the sun, the moon, and the earth are in the same straight line, that is, when the force of the sun conspires with that of the moon, and that the lowest tides take place when the lines drawn from the sun and moon to the earth are at right angles to each other, that is, when the force of the sun acts in opposition to that...
Página 298 - Herculis. The velocity of this motion is such that the sun, with the whole cortege of bodies depending on him, advances annually in the direction indicated, through a space equal to 1.623 radii of the terrestrial orbit or one hundred and fifty-four millions of miles.
Página 13 - The vertical circle which passes through the north and south points of the horizon is the same as the celestial meridian, which will be defined hereafter (32).
Página 237 - ... feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across; Saturn a small orange, on a circle of four-fifths of a mile; Uranus a full-sized cherry, or small plum, upon the circumference of a circle more than a mile and a half, and Neptune a good-sized plum on a circle about two miles and a half in diameter.
Página 82 - It is found to be always exactly perpendicular to the plane of the horizon; or, to a plane tangent to the surface of the earth at the point of observation.
Página 279 - ... reduce the intensity to onesixteenth : in short, we thus demonstrate the law that the intensity of light diminishes as the square of the distance increases. This is the celebrated law of Inverse Squares as applied to light.