  Using our semi-linear inversion method, we measure the mass profile of the
lens galaxy in the Einstein ring system 0047-2808. The lens is modelled as a
baryonic component following the observed light, embedded in a dark matter
generalised NFW halo. The semi-linear method makes full use of the information
content in the ring image. We determine an unevolved B-band mass to light ratio
for the baryons of 3.05 +0.45 -0.86 h_65 M_sol/L_sol (95% CL), accounting for
65% of the total projected mass within the radius of 1.16'' traced by the ring.
This result is obtained without need of dynamical measurements. The inner
logarithmic slope of the halo is found to be 0.87 +0.69 -0.61 (95% CL). We find
that the halo is fairly well aligned with the light but has only half the
ellipticity.
