Outlines of Astronomy |
From inside the book
Results 1-5 of 65
Page 31
... disk of the Sun is the name given to that part of the photosphere which we can see at any one time ; so that in speaking of the disk we are speaking of the Sun as it appears and not as it is . The edge of the disk is called the limb of ...
... disk of the Sun is the name given to that part of the photosphere which we can see at any one time ; so that in speaking of the disk we are speaking of the Sun as it appears and not as it is . The edge of the disk is called the limb of ...
Page 32
... disk is brightest in the middle , let us first consider why the whole Sun usually seems brighter the higher it seems to be in the sky . When the Sun has just risen or is about to set , we look at it along the ground , so that between us ...
... disk is brightest in the middle , let us first consider why the whole Sun usually seems brighter the higher it seems to be in the sky . When the Sun has just risen or is about to set , we look at it along the ground , so that between us ...
Page 33
... disk which has just been explained is darker in some places than in others no nearer to the limb . In many parts of the disk we usually see a mixture of brighter and darker specks , which present what is called a granulated appearance ...
... disk which has just been explained is darker in some places than in others no nearer to the limb . In many parts of the disk we usually see a mixture of brighter and darker specks , which present what is called a granulated appearance ...
Page 34
... disk are perhaps due to masses of absorbent vapors occupying cavities or hollows in the photosphere . Whether the matter of the photosphere is liquid or gaseous , or composed of clouds of liquid or solid particles floating in gases , it ...
... disk are perhaps due to masses of absorbent vapors occupying cavities or hollows in the photosphere . Whether the matter of the photosphere is liquid or gaseous , or composed of clouds of liquid or solid particles floating in gases , it ...
Page 35
... disk from the following to the preceding limb . Since sometimes one and sometimes the other pole of the Sun is upon the disk , according to the situation of the Earth and Sun with respect to each other , the paths of the spots across the ...
... disk from the following to the preceding limb . Since sometimes one and sometimes the other pole of the Sun is upon the disk , according to the situation of the Earth and Sun with respect to each other , the paths of the spots across the ...
Other editions - View all
Common terms and phrases
aphelion appear astronomers atmosphere axis ball body bright calculations called celestial objects celestial sphere circle clock clouds comet compared consider course cross determined direction disk distance Earth Earth's atmosphere Earth's centre Earth's orbit Earth's rotation ecliptic equal equator equatorial stars exactly eye-piece fact farther Hence Hipparchus horizon Jupiter kind known latitude law of gravitation laws of motion length lens less light limb longitude look Mars mass mean measure ment meridian meteors miles Moon Moon's movement nearer nearly nodes north pole northern noticed nutation object-glass observations opposite orbit parallax particular passing pencil perihelion perpendicular photosphere plane prism refraction regard retrograde revolution right ascension ring round the Sun satellites Saturn seen shape side sidereal sidereal day solstice sometimes spectrum spots stars straight line Sun's suppose surface telescope terrestrial place tion transit triangle Uranus usually Venus vernal equinox vertical visual angle zenith
Popular passages
Page 82 - The squares of the periodic times of any two planets are to each other, in the same proportion as the cubes of their mean distances from the sun.
Page 201 - the eclipse presented, during the total obscuration, a vision magnificent beyond description. As a centre stood the full and intensely black disc of the moon, surrounded by an aureola of soft bright light, through which shot out, as if from the circumference of the moon, straight massive silvery rays, seeming distinct and separate from each other, to a distance of two or three diameters of the lunar disc ; the whole spectacle showing as upon a background of diffused rose-coloured light...
Page 320 - It will be seen that we multiply the denominator of the dividend by the numerator of the divisor for the denominator of the quotient, and the numerator of the dividend by the denominator of the divisor for the numerator of the quotient.
Page 224 - Surfaces of spheres are to each other as the squares of their diameters.
Page 298 - ... directly proportional to the product of the masses and inversely proportional to the square of the distance between them.
Page 390 - The limits of the obliquity of the apparent ecliptic to the equator ^are 24° 35' 58" and 21° 58' 36"; whence it follows that the greatest and least declinations of the sun at the solstices can never differ from each other to any greater extent than 2° 37
Page ii - BROTHERS, In the Office of the Librarian of Congress at Washington. CAMBRIDGE: PRESS OF JOHN WILSON AND SON.
Page 375 - Astronomical Observations and Researches made at Dunsink, the Observatory of Trinity College, Dublin,
Page 193 - The greatest number of eclipses that can happen in a year is seven; five of the sun and two of the moon, or four of the sun and three of the moon.
Page 296 - Every body continues in its state of rest or of uniform rectilinear motion unless compelled to change its state by forces impressed upon it.