There may be another group that would be better for this type of
question (in fact, I could probably just ask Bill Gray directly),
but we'll see if I can tick anyone off in this group first! ;-)

I have transform matrices for converting ecliptic or galactic to
equatorial (transforms ecliptic or galactic logitude/latitude to
J2000 equatorial coordinates). They are:

ECLIPTIC
1.0 0.0 0.0
0.0 0.917482062 0.397777156
0.0 -0.397777156 0.917482062

GALACTIC
-0.0548755604 -0.8734370902 -0.4838350155
0.4941094279 -0.4448296300 0.7469822445
-0.8676661490 -0.1980763734 0.4559837762

Now, I need the same thing for Supergalactic. But I can't find it
anywhere. I know that the Supergalactic north pole is at (J2000) 18
55 01.0 +15 42 32 and that its origin is defined as 137.37 degrees
galactic long., 0.0 degrees galactic lat. But how does that
translate to a matrix I can use in my precession/transformation code?

Anyone got the numbers?

-Christopher