Emily Dickinson Lexicon

DE-SCEN'SION, n. [L. descensio.]

1. The act of going downward; descent; a falling or sinking; declension; degradation.
2. In astronomy, right descension is an arch of the equinoctial, intercepted between the next equinoctial point and the intersection of the meridian, passing through the center of the object, at its setting, in a right sphere. – Encyc. Oblique descension, is an arch of the equinoctial, intercepted between the next equinoctial point and the horizon, passing through the center of the object, at its setting, in an oblique sphere. – Encyc. Oblique descension, is an arch or the equator which descends with the sun below the horizon of an oblique sphere. – Bailey. Descension of a sign, is an arch of the equator, which sets with such a sign or part of the zodiac, or any planet in it. – Bailey. Right descension of a sign, is an arch of the equator, which descends with the sign below the horizon of a right sphere; or the time the sign is setting in a right sphere. – Bailey.