Locating astronomical objects with reference to equatorial coordinate system on the celestial sphere is called spherical astronomy. It is one of the oldest observational astronomical branch which uses various mathematical concepts specifically, geometry calculation for measurement estimation. It can also be referred as positional astronomy generally envelops entire earth geometry to analysis.
Basically, it includes different parameters of earth's geometry along with its equator in line to celestial objects which finally gives location of these objects in particular year. All in all, it is a specialized science field in astronomy which first observes around space envelope and finally gives data about location of individual space objects with respect to tome.