I found this book hard going. The Copernicus that Banville depicts is an inscrutable unemotional scholar that it is difficult to warm to.
I don't get a sense of what drove him or how Copernicus developed his heliocentric theory. Too much is left unsaid and yet too much is aid about the sexual proclivities of the main characters. Why?
So the medieval mind may have had different sensibilities about sexual matters but it was tiresome how often the author descends into crudeness. I don't understand how it furthered the story or gave any greater insight.
There was one bit of philosophising about what it all meant in a dialogue between Copernicus and Rheticus that was the closest to giving us a glimpse of the Copernicus character but by that stage I couldn't care less.

If as imagined, the life of Copernicus was grim and wary, interrupted with one or two happy events. Tormented by family, peers, and self-doubt, he felt safest pursuing his own theories in a sort of solitary.

Not close to my favorites by this author, however the extended passage of his dying was extraordinary. Redeemed the tale, in my view.

Very dull. Not only was the central character presented as an automaton, his ideas were alluded to with any of the excitement or interest they might have inspired being sucked out of them. I am pleased only to have freed up one more space on my book shelf!

strange character this doctor copernicus, but very credible. the last pages, his last hours on earth, are sublime in form and content.