More work on comets and first thoughts on a detailed PhD proposal

I have been pulling together some thoughts from the various sources I have acquired relating to the interpretation of comets in the late 1500s. As the new world-systems developed and began to fit it out, so such events provided battle grounds. The work Appian and others to suggest that the tail of comets always point away from the sun. That by Maestlin and Tycho Brahe to establish that comets were "above" the Moon. Yet Galileo and Kepler got comets pretty much wrong - Galileo's commitment to the Aristotelian belief in their locations, Kepler's that they move in straight lines. Would that Kepler had realised that they moved in extremely eccentric ellipses with the sun at one focus (i.e. that they followed Kepler's first two laws).

I have been putting together a piece based on a number of pictures that I have come across that illustrate some of this rather well - pictures of the Great Comet of 1577, Tycho's diagrams, modern reconstructions of its path, and so on. I have 7 pictures and am planning to write a paper based on these in some way. I will then submit this to John Milton for comments and then use it as an example of my written work for my PhD application.

Peter Apian's demonstration that the tails of comets point away from the Sun - the comet of 1532

My current PhD thoughts centre on the two main novelties of the late sixteenth / early seventeenth century, namely comets and the two nova (1572 and 1604). Of course comets aren't actually that uncommon, but the ability to make more precise observations of them is novel, as is their location within the heavens rather than as an atmospheric phenomenon. Of course the two novas are very different and really are novel. So I would like to look in detail at Tycho's work on comets and the nova of 1572, and Kepler's work on the nova of 1604 and Maestlin on each. What arguments did they use, what counter arguments were put by opponents. After all, Hellman claimed that only 5 astronomers accepted the view that the comet of 1577 was above the moon. The "rhetoric of novelty" seems to me to be a tentative theme that would sound suitable for a PhD application?