For the past three or four days, I have been sorting out the huge pile of academic articles at the far end of the study. And in the last day or so, I have actually done a little academic work, the first for ages. I have taken notes on five or six articles, mainly from the Stanford Encyclopedia of Philosophy and today I had a more challenging target - to read and take notes on Rheticus's Narratio Primo, the world's first printed text on Copernicanism.
But anyone expecting a tightly argued case for heliocentrism would be disappointed. Much of the work is highly technical and though it is clear that Rheticus is a committed Copernican, he is not very upfront in his arguments. His most sustained argument concerns the ability of heliocentrism to "explain" retrograde motion. Here Rheticus avoids using any diagrams and describes the explanation. This is a pretty technical description, but surprisingly clear I thought, but then I knew what he was trying to say.
Lots of nice photo montages on the internet of Mars in retrograde motion. And it is even clear that Mars is at its biggest and brightest midway through retrogression.
Though Rheticus does emphasize the harmony of heliocentrism and notes how the overall system must be bound tightly together (changing one bit changes it all), he does not argue for some of the obvious simplifications e.g. that the relative distances of the planets from the sun can be fixed, or that the length of each planet's year becomes more contstant.
Nonetheless, I have really enjoyed reading such a detailed text. I can see this becoming a big part of my day-to-day life again.