>Thanks - I'll check those out.
>
>>Most definitions I've found make no distinction between Julian Day Number & Date, other than the Julian Day starts at noon - so you need the time to get a correspondence between the day number & the date.
>>http://serendipity.magnet.ch/hermetic/cal_stud/jdn.htm
>>
>>This site gives an alternative - 5 digits, the first 2 being the last two digits of the year & then a day number from 1-365(6).
>>http://www.electric-words.com/dict/j/juliandateday.html

Heres a fairly clear definition :
"Julian Day Number is a count of days elapsed since Greenwich mean noon on 1 January 4713 B.C., Julian proleptic calendar. The Julian Date is the Julian day number followed by the fraction of the day elapsed since the preceding noon."
http://tycho.usno.navy.mil/systime.html