According to Synesius of Ptolemais (4th century) he made the first astrolabion: this may have been an armillary sphere (which Ptolemy however says he constructed, in Almagest V.1); or the predecessor of the planar instrument called astrolabe (also mentioned by Theon of Alexandria).
Prema Sineziju iz Kirene (4. stoljeće) Hiparh je napravio prvi astrolabion što bi mogla biti armilarna sfera (za koju Ptolomej ipak kaže da ju je on konstruirao; Almagest V.1) ili prethodnik planarnih instrumenata nazvanih astrolab (kojeg spominje Teon iz Aleksandrije).