From the Wikipedia:
in reply to Converting Julian Dates to Text
The Julian date (JD) is the interval of time in days and fractions of a day, since 4713 BC January 1, Greenwich noon, Julian proleptic calendar.
Excel dates have unfortunately absolutely nothing to do with the Julian Date system.
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James