White Dwarf.

In a distant future New York medical student Driscoll Rampart accomplishes his internship at Rusta, a rural planet that doesn't revolve around its axis and therefore is divided into contrasting halves of eternal day vs. eternal night. One is a Victorian-styled colony, the other a medieval kingdom. Both leave Rampart in a state of constant wonder, as he finds his way among humans and aliens, strange dreams and even stranger reality, a dark keep and a red sea, and more universal matters of war and peace, good and bad, love and hate and sickness and health.