The Collaborative International Dictionary
Oblique descension
Descension \De*scen"sion\, n. [OF. descension, L. descensio. See Descent.] The act of going downward; descent; falling or sinking; declension; degradation.
Oblique descension (Astron.), the degree or arc of the equator which descends, with a celestial object, below the horizon of an oblique sphere.
Right descension, the degree or arc of the equator which descends below the horizon of a right sphere at the same time with the object. [Obs.]