Isayensi yezinkanyezi (kusuka esiGrekini: ἀστρονομία, okusho ukuthi isayensi efunda imithetho yezinkanyezi) yisayensi yemvelo ecwaninga izinto zasezulwini nezinto ezenzekayo. Isebenzisa izibalo, i-physics, ne-chemistry ukuze ichaze imvelaphi yazo nokuziphendukela kwemvelo. Izinto ezithakazelisayo zifaka amaplanethi, izinyanga, izinkanyezi, ama-nebulae, imithala nezinkanyezi ezinomsila. Izimo ezihambisanayo zifaka ukuqhuma kwe-supernova, ukuqhuma kwe-gamma ray, ama-quasar, ama-blazars, ama-pulsars, nemisebe yangemuva ye-cosmic microwave. Ngokuvamile, isayensi yezinkanyezi ifunda konke okuvela ngaphesheya komkhathi womhlaba. ICosmology igatsha lezinkanyezi elifunda indawo isiyonke. Umlando Izikhathi zasendulo Ezikhathini zokuqala zomlando, isayensi yezinkanyezi yayiqukethe kuphela ukubuka nokubikezela ukunyakaza kwezinto ezibonakalayo ngeso lenyama. Kwezinye izindawo, amasiko okuqala ahlanganisa izinto zobuciko ezinkulu okungenzeka ukuthi zazinenjongo ethile yezinkanyezi. Ngaphezu kokusetshenziswa kwazo okuyimikhosi, lezi zikhungo zingasetshenziswa ukuthola izinkathi zonyaka, into ebalulekile ekwazini ukuthi kutshalwa nini izitshalo nasekuqondeni ubude bonyaka. Ngaphambi kokuba kusungulwe amathuluzi anjenge-telescope, ukutadisha izinkanyezi kusenesikhathi kwenziwa ngokusebenzisa iso lenyama. Njengoba impucuko yathuthuka, ikakhulukazi eMesopotamiya, eGrisi, ePersia, eNdiya, eChina, eGibhithe naseCentral America, kwaqoqwa izingqapheli zezinkanyezi kwaqala ukuvela nemibono ngobunjalo bomkhathi.