From Longman Dictionary of Contemporary Englishastronomeras‧tron‧o‧mer /əˈstrɒnəmə $ əˈstrɑːnəmər/ noun [countable] a scientist who studies the stars and planets
Examples from the Corpus
astronomer• During his own tenure as astronomer royal, from 1720 to 1742, Halley studiously tracked the moon.• Then Bradley, the astronomer royal, died in July. 