Dear Angelo, sorry, but I have made a mistake during the data input, and the correct answer, following the method of T.C.Van Flandern and K.F.Pulkkinen for April 18, 1693 (0h ET) is
JD = 2339523.5
RA = 1h 46m 12s
Decl = 10° 59' 16"
R = 1.005750
I beg your pardon!
Paolo Gregorio
