All but the smallest position circles, when the body is close to the zenith (say above 85° altitude), are large enough for a small portion to be considered a straight line.
Zonke ngaphandle kwezangqana zobume xa umzimba lowo ukufutshane kwincam yezulu (mhlawumbi kwisibanzi esingaphezu kwamaqondo angu 85) zinkulu ngokwaneleyo ukuba isabelwano singabalelwa ekubeni ngumgca othe tye.