Galileo's finding that Venus goes through these, like the moon, was the 1st direct evidence for Copernican ideas
These observations were further strong evidence that Earth is not the 
center of... [DOC] [TLE] Galileo's Double Star - arXiv.org [PAR] these notes, his later reference in his Dialogue to using double stars as a ... that 
Galileo was among the first astronomers to observe a double star.