Fourteen Weeks in Descriptive Astronomy |
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Page 94
... inclination of its axis is 75 ° , as some as- tronomers hold , its tropics must be 75 ° from the equator , and its polar circles 75 ° from the poles . The torrid zone is , therefore , 150 ° in width . The torrid and frigid zones ...
... inclination of its axis is 75 ° , as some as- tronomers hold , its tropics must be 75 ° from the equator , and its polar circles 75 ° from the poles . The torrid zone is , therefore , 150 ° in width . The torrid and frigid zones ...
Page 110
... inclined 231 ° from a perpendicular to its orbit . This angle is called the obliquity of the ecliptic . II . Parallelism of the axis . - In all parts of the orbit , the axis of the earth is parallel to itself and constantly points ...
... inclined 231 ° from a perpendicular to its orbit . This angle is called the obliquity of the ecliptic . II . Parallelism of the axis . - In all parts of the orbit , the axis of the earth is parallel to itself and constantly points ...
Page 121
... inclination of the axis of the earth , CP , to CQ , the pole of the ecliptic , remains unchanged ; but as it must turn with the equator , its position is moved from CP to CP ' , and it passes slowly around through a portion of a circle ...
... inclination of the axis of the earth , CP , to CQ , the pole of the ecliptic , remains unchanged ; but as it must turn with the equator , its position is moved from CP to CP ' , and it passes slowly around through a portion of a circle ...
Page 124
... inclination of the axis CP toward C Q , and make it more nearly perpendic- ular to the ecliptic . This would be the result if the earth were not revolving upon its axis . Let us con- sider the case of a mountain near the equator . This ...
... inclination of the axis CP toward C Q , and make it more nearly perpendic- ular to the ecliptic . This would be the result if the earth were not revolving upon its axis . Let us con- sider the case of a mountain near the equator . This ...
Page 125
... inclination unchanged , around CQ , the pole of the ecliptic , describing , in about 26,000 years , a small circle twice 23 ° 28 ' in diameter . Precession illustrated in the spinning of a top . - This motion of the earth's axis is most ...
... inclination unchanged , around CQ , the pole of the ecliptic , describing , in about 26,000 years , a small circle twice 23 ° 28 ' in diameter . Precession illustrated in the spinning of a top . - This motion of the earth's axis is most ...
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Common terms and phrases
ancients Andromeda angle aphelion appear Aries astronomers atmosphere axis Boötes bright brilliant Canis Minor Capricornus Cassiopeia cause Celestial Sphere centre Cepheus circle color comet conjunction constellation Cor Caroli dark density Describe diameter disk earth east ecliptic equal equator equinoctial figure fixed stars full moon globe heat heavenly bodies heavens Hercules Herschel horizon inclined inferior conjunction inferior planet Jupiter latitude length light luminous lunar Lyra magnitude Mars mean distance Mercury meridian meteors miles moon's motion move naked eye nearly nebula Neptune night node north pole Orion parallax pass path penumbra perihelion Perseus Pisces polar Polaris precession rays revolve ring rising Saturn seasons seen shine side sidereal sidereal day solar day solar system solstice space spots summer sun's surface synodic revolution tance Taurus telescope theory tion Uranus Ursa Major Ursa Minor varies velocity Venus vernal equinox visible winter Zodiac