Some of the people referred to on this site are real people. Others are invented characters featured in the novel.
Among the major characters, Clyde Tombaugh, V.M. Slipher, and Constance Lowell are real people; other, minor real characters include Harlow Shapley, Cecilia Payne, Percival Lowell, and some members of the Tombaugh family.
But I have treated all characters as fictional, in that I have allowed myself to have them say and do anything I want, given very broad parameters as I understand the facts to have been. This site is intended as an expansion of the world of the novel, not as a guide to the truth of anything.
For a complete guide to who is real and who isn’t, go here.