Answer: copernicus

AnswerCrossword Clue
COPERNICUSAstronomer who claimed the Earth orbited the Sun
COPERNICUSProminent lunar crater
COPERNICUSFather of Modern Astronomy
COPERNICUSPioneer in astronomy, c. 1530.
COPERNICUSAstronomy's father
COPERNICUSAstronomer born in Torun, Poland
COPERNICUSHe placed the sun at the center of the universe
COPERNICUSPioneer in heliocentric theory