John Booker (1601 - 1667)

Harvey accepts Booker's birth year of 1601 "with reservations" because of a confusion of Old Style dating. Booker himself provides a date of 23 March 1601, but in the usual style of notation this should have been 1601/2. The year began at the Vernal Equinox which occurs around the 21 March NS, 10 March OS, so the double notation of 1601/2 was usually used around the early part of the year. It is likely that 1601 in this case refers to 1600/1, thus the date of Booker's birth would be as noted above. Gadbury used this date and it remained unchallenged by his arch-enemy, John Patridge.

Booker and Lilly were friends although that was not so at their first association when Booker was the Licenser of books on "Mathematicks, Almanacks, and Prognostications". After Booker had made a great many edits to Lilly's "Merlinus Anglicus Junior" of 1644, to the extent that Lilly appealed to Parliament who overruled Booker.

Harvey has used 8.00 am local apparent time even though Booker himself says that he was born at 8.10 am. The former is an "estimate" time according to Gadbury that had been given by John Booker. The following chart is set for 8.10 am according to Booker, nevertheless, this does not mean that the resulting chart is identical to that set by Booker or other astrologers of that time.