I roto i te whakaahuatanga, te pokapū o te deferent e kore te whenua, engari ko te wahi tohu X, hanga reira excentric (mai i te Greek ἐκ ec- tikanga "mai i", me te κέντρον kentron tikanga "pokapū"), i nei te wahi e mau tona ingoa. Heoi, e kore i tino ōrite te pūnaha i wātea i roto i te wa o Ptolemy mataaratanga, ahakoa i nui ake te whakapai ake i runga i te pūnaha Hipparchus. tino kitea te rahi o te aorangi retrograde o te aorangi (i roto i te mea o Mars) e kia nui, me te iti iho i te wā e tūmanakohia ana, hua i roto i 30 nekehanga o ia epicycle rite tonu rite rite.
Ngā tohunga whetū Kariki