Related issues thumbnail|right| A United States Marine lance corporal plots the direction and elevation of a mortar before firing. Before a gun or launcher can be aimed, it must be oriented towards a known azimuth, or at least towards a target area. Initially, the angle between the aiming point and target area is deduced, or estimated, and set on the azimuth sight. Each gun is then laid on the aiming point, with this angle in order to keep them aimed roughly parallel to each other. However, for artillery another instrument, called either a director (United Kingdom) or aiming circle (United States), became widespread and eventually the primary method of orienting guns in most if not all armies. After being oriented and pointed in the required direction a gun recorded angles to one or more aiming points. Such early directors were the progenitors of the later general class of directors.
relAteD IssuES THuMBnAiL|riGht| a unitEd states MarinE lance corporaL ploTs ThE DirEctIOn And ELeVaTion oF a mortAr bEForE FIrInG. befORe a Gun or lAunchEr Can be Aimed, it mUST BE ORientEd ToWArdS a kNOwn Azimuth, Or at least towards a tArgeT Area. initially, THE anGle between THe AiMInG PoiNT ANd TaRgEt areA Is DedUced, Or eSTIMaTed, AnD set oN the Azimuth Sight. eAch gUn is then LAid on ThE aiming poINT, witH thiS AnGle iN oRdeR to keeP theM aimed roUgHly ParalLeL to eAcH other. hOwEVer, for artIlLERY aNOTHer iNsTruMent, cAlLEd either a dirEctoR (uniTed Kingdom) Or AimING cIrcle (UnitEd StaTes), BeCame widEsPreaD anD evEntuALLy tHE primary mEthod of orieNtinG gUNs in most if not aLl aRmiES. aFTEr being orienteD anD POinted iN ThE RequiREd DireCtIoN a gUn RecoRded AngLES To One OR more aiMIng poiNts. SUcH eArly DirECTors were the progenitorS of ThE latEr generAL ClAss of dIrecTORS.