Letters on Astronomy: Addressed to a Lady; in which the Elements of the Science are Familiarly Explained in Connexion with Its Literary HistoryMarsh, Capen, Lyon and Webb, 1841 - 419 |
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Strona 21
... Hence , the axis of the earth is the axis of the equator , and its poles are the poles of the equator . The intersection of the plane of the equa- tor with the surface of the earth constitutes the terres- trial , and its intersection ...
... Hence , the axis of the earth is the axis of the equator , and its poles are the poles of the equator . The intersection of the plane of the equa- tor with the surface of the earth constitutes the terres- trial , and its intersection ...
Strona 30
... Hence the compass shows the azimuth of an object , or how many degrees it lies east or west of the meridian . It is obvious , that the larger the graduated circle is , the more minutely its limb may be divided . If the cir- cle is one ...
... Hence the compass shows the azimuth of an object , or how many degrees it lies east or west of the meridian . It is obvious , that the larger the graduated circle is , the more minutely its limb may be divided . If the cir- cle is one ...
Strona 33
... Hence the principle of the telescope is as fol- lows : By means of the object - glass , ( in the refracting telescope , ) or by the concave mirror , ( in the reflecting telescope , ) we form an image of the object , and mag- nify that ...
... Hence the principle of the telescope is as fol- lows : By means of the object - glass , ( in the refracting telescope , ) or by the concave mirror , ( in the reflecting telescope , ) we form an image of the object , and mag- nify that ...
Strona 35
... Hence , large achromatic telescopes are very expensive , being valued in proportion to the cubes of their diameters ; that is , if a telescope whose aperture ( as the breadth of the object - glass is technically called ) is two inches ...
... Hence , large achromatic telescopes are very expensive , being valued in proportion to the cubes of their diameters ; that is , if a telescope whose aperture ( as the breadth of the object - glass is technically called ) is two inches ...
Strona 38
... Hence , the lower powers generally afford the most agreeable views , because they give the clearest light , and take in the largest space . The several cir- cumstances which influence the qualities of a telescope are , illuminating ...
... Hence , the lower powers generally afford the most agreeable views , because they give the clearest light , and take in the largest space . The several cir- cumstances which influence the qualities of a telescope are , illuminating ...
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angle appear ascertain astronomers atmosphere attraction axis called celestial centre circle comet conjunction constellation degrees diameter direction discovery disk distance diurnal motion doctrine double stars earth ecliptic equal equator equinox exhibited fact fixed stars force Galileo globe gravity greater greatest half Halley's comet heavenly bodies heavens Hence Herschel horizon hundred inferior conjunction instrument John Herschel Jupiter Kepler latitude laws length less light longitude lunar lunar eclipse magnitude measure Mercury meridian meteors millions of miles minutes moon moon's motion move Nature nearer nearly node objects observations opposite orbit parallax passing perihelion period phenomena planetary planets pole respect revolve right ascension ring round satellites Saturn seen shadow side space spectator sphere sun's superior planets supposed surface telescope thousand tides tion truth Tycho Tycho Brahe universal gravitation Uranus velocity Venus vernal equinox visible west to east