   Copernicus’s fame and book made its way across Europe over the next fifty years, and a second edition was brought out in  1566.[13]   As Gingerich’s census of the extant copies showed, the book was read and commented on by astronomers. (For a fuller discussion of reactions, see Omodeo.) Gingerich (2004, 55) noted “the majority of sixteenth-century astronomers thought eliminating the equant was Copernicus’ big achievement.”