Here is a quick ruby script which can be used for calculating the Julian day. You can either download it by clicking here or simply copy and paste it.
These calculations were taken from the book Astronomical Algorithms
# Begin Julian Day Calculation (Meeus Pages 59-61) vvvv t= Time.now #### #You can change these variables and calculate the JD for a specific #date if you want. Be sure though that you compensate for #your time zone if changing the hour. y = t.gmtime.year m = t.gmtime.month d = t.gmtime.day + t.gmtime.hour/24.to_f + t.gmtime.min/1440.to_f + t.gmtime.sec/86400.to_f #### if m>2 y=y m=m else y = y-1 m = m+12 end a = (y/100).to_int b = 2 - a + (a/4).to_int jd = (365.25 * (y+4716)).to_int + (30.6001 * (m+1)).to_int + d + b + -1524.5 # End Julian Day Calculation^^^^ puts jd
