Elements of astronomy ..with explanatory notes, and questions for examination . at no eclipse can occur; although the sun,moon, and earth are so situated in every other respectas to give rise to this phenomenon. When it does reachthe earth, the space that it covers on the surface of thelatter, will depend upon the position of the end of theshadow in reference to the surface of the earth. If theend of the shadow just touches the earth, there will be aneclipse only at the place where it touches. But if thepoint where the shadow would terminate, if the earthdid not interpose, is situated, as at F
Elements of astronomy ..with explanatory notes, and questions for examination . at no eclipse can occur; although the sun,moon, and earth are so situated in every other respectas to give rise to this phenomenon. When it does reachthe earth, the space that it covers on the surface of thelatter, will depend upon the position of the end of theshadow in reference to the surface of the earth. If theend of the shadow just touches the earth, there will be aneclipse only at the place where it touches. But if thepoint where the shadow would terminate, if the earthdid not interpose, is situated, as at F in Fig. 62, far on theother side of the earth, then the eclipse will be visiblethroughout a region of considerable extent. The largestextent of surface on the earth, covered at once by theshadow of the moon is about 180 miles. 365. The lunar shadow like that of the earth, has alsoits penumbra, which partially obscures our globe. Thegreatest breadth of terrestrial surface enclosed by thepenumbra is nearly 5,000 miles. 366. In Fig. 62, this subject is illustrated, S here rep-. SOLAR ECLXPBE. resents the sun, M the moon, and E the earth. Theform of the shadow is denned by the line CF, and DF,a portion of the shadow is however cut off by the inter-position of the earth. The breadth of the shadow on theearth is represented by the distance from O to P, andthe breadth of the penumbra on each side of the shadow,by the curved lines GO and PH. 367. Altitude of the Moon—Its effect on Eclip-ses. Since the moon is nearer to the surface of the earthwhen in the zenith than when upon the horizon, by about When will no eclipse occur? Upon what does the extent of terrestrial surface coveredby the shadow depend ? Give the two illustrations? What is the greatest extent ofsurface obscured by the shadow 1 State wliut is said respecting the penumbra and itsbreadth 1 Illustrate from Fig. 62. ALTITUDE OF THE MOON. 183 4,000 miles, it may happen that a solar eclipse #takesplace in one part of the wor
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Keywords: ., bookcentury1800, bookdecade1850, bookidelem, booksubjectastronomy
