need help converting UTC time to UT1

[ncc1701d]

Hello, I could use some help. I get confused when trying to integrate milliseconds and leap seconds into my conversions.

Using formula which i believe is correct. UT1 = UTC + DUT1

convert UTC date that looks like this

2003-05-23T09:34:12:348z (UTC)

and
using chart found here:
http://www.nist.gov/pml/div688/grp50/leapsecond.cfm

Start Date Time DUT1 Correction
2005-03-17 0000 UTC - 0.6 s
2004-04-29 0000 UTC - 0.5 s
2003-04-03 0000 UTC - 0.4 s
2002-10-24 0000 UTC - 0.3 s
2002-02-14 0000 UTC - 0.2 s
2001-10-04 0000 UTC - 0.1 s
2001-03-01 0000 UTC +0.0 s


I want to convert my UTC or any UTC date to UT1
That looks something in the form 12.34 seconds.
2003-04-23T09:34:12.34

12.34 seconds in not correct answer but you notice there is no more : but now its a decimal number with 2 decimal places.

2003-05-23T09:34:12 without milliseconds (.348z) converted to julian day
is JD 2452782.898750 if that helps. My confusion revolves around seconds and milliseconds section.

The date iam converting isnt precisely on one of the days of the chart so that adds
little more confusion on the subject.

Any help appreciated.

 

[ncc1701d]

ok i found answer
http://maia.usno.navy.mil/
provides DUT1 values for every day