If I ask Mathematica for the Julian Date for the battle of Agincourt with
WolframAlpha["battle of agincourt date"]
it reports 2238175
. But this does not agree with the value of 2238183.50
reported by the US Naval Observatory.
Why are these reported dates different?
jd[]
function from here:jd[{1415, 10, 25}, "Calendar" -> "Julian"]
matches USNO's output, andjd[{1415, 10, 25}, "Calendar" -> "Gregorian"]
is close to Alpha's. $\endgroup$JulianDate[]
say as much: "All referenced dates are using the proleptic Gregorian calendar." $\endgroup$.5
in the USNO date. $\endgroup$