Terzan 11
 3 iterations.
Chebyshev coeffients a(0)T_0(u)+a(1)T_1(u)+..., where u is log (r/arcsec) mapped to [-1,1]
 a(0)=     0.653 +-  0.380
 a(1)=     0.896 +-  0.519
 a(2)=     0.298 +-  0.494
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c)^2, r_c=1.47
 a(0)=    -0.2554
 a(1)=    -0.6428
 a(2)=     1.9530
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set