The text was transcribed directly from the original printed version of 1596. Obvious typographical errors have been corrected, and a few corrections have been taken from the final edition of 1611. Page breaks are indicated by a page reference enclosed in pointy brackets. Italics are used as in the original, i.e. generally to indicate quotations. E.g. the text begins with a quotation from Sacrobosco's Sphere, on which Clavius, like many other medieval and early modern astronomy educators, wrote his commentary.
Italics also indicate titles.
The original contains marginal notes, which here appear enclosed by hyphens. Images, scanned from the 1596 edition, appear in roughly the same place with respect to the text as in the printed book.