in astronomy, is either right or oblique.

Right Descension is an arch of the equinoctial, intercepted between the next equinoctial point and the interlection of the meridian, passing through the centre of the object, at its setting, in a right sphere.

Oblique Descension, an arch of the equinoctial, intercepted: DES (418) DES

tercepted between the next equinoctial point and the horizon, passing through the centre of the object; at its setting, in an oblique sphere.