In my searching for books on Amazon, I found a book called Astronomical Algorithms by Jean Meeus. It was claimed to be the first book that made astronomical calculations available to the casual astronomers. It was focused on “calculators” but since the first edition was written in 1979, an iPhone today would seem like a mainframe computer. I had to get this book. I also got his original Astronomical Formulae for Calculators.
This books will be the basis for the Astronomy Calculator so I am in his debt.