Fabrica et vsvs : instrvmenti ad horologiorvm descriptionem peropportvni : accessit ratio describendarvm horarum a meridie & media nocte exquisitissima, & nunquam ante hac in lucem edita (1586)
Clavius, Christoph, 1538-1612 · Romae : Apud Bartholomaeum Grassium · leaf 16
Sundials
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
