Julian day conversion

NOAA keeps a handy Javascript application at the webpage below for converting a normal calendar date into Julian days. The catch is that it does this conversion using January 1 of any year as Julian day 1, rather than calculating Julian day from noon on January 1, 4713 BC. Most sites on the web give you a Julian date starting from this ancient date. For certain calculations, it is just simpler to express your date within a year in Julian days (i.e. 1 - 365, 366 on a leap year). This NOAA calculator does this for you.

http://autochart.pmel.noaa.gov:1776/autochart/date2jday.html