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In astronomy, the culmination of a planet, star or constellation is its transit over an observer's meridian.〔p. 8, ''The Cambridge Guide to the Constellations'', Michael E. Bakich, Cambridge University Press, 1995, ISBN 0521449219.〕〔entry for "culmination", p. 110, ''The Facts on File Dictionary of Astronomy'', John Daintith, William Gould, Infobase Publishing, 2009, ISBN 1438109326.〕 During a sidereal day, an astronomical object crosses the meridian twice: once at its upper culmination, when it is (approximately) at its highest point as seen from the earth, and once at its lower culmination, its (approximately) lowest point. Often, culmination is used to mean upper culmination.〔〔〔Entry for "meridian", p. 993, ''The National Enyclopaedia'', library edition, vol. 8, London: William Mackenzie, 69 Ludgate Hill, E.C.; Edinburgh and Glasgow. ()〕 The altitude of an object in degrees at its upper culmination is equal to (90 − L + D), where L is the observer's latitude and D is the object's declination. == Cases == The three cases are dependent on the observer's latitude and the declination of the celestial body: *The object is above the horizon even at its lower culmination; i.e. if |declination + latitude| > 90° (i.e. if in absolute value the declination is more than the colatitude, in the corresponding hemisphere) *The object is below the horizon even at its upper culmination; i.e. if |declination − latitude| > 90° (i.e. if in absolute value the declination is more than the colatitude, in the opposite hemisphere) *The upper culmination is above and the lower below the horizon, so the body is observed to rise and set daily; in the other cases (i.e. if in absolute value the declination is less than the colatitude) The third case applies for objects in a part of the full sky equal to the cosine of the latitude (at the equator it applies for all objects, because the sky turns around the horizontal north-south line; at the poles it applies for none, because the sky turns around the vertical line). The first and second case each apply for half of the remaining sky. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「culmination」の詳細全文を読む スポンサード リンク
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