NGC6388
 4 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)=    18.618 +-  0.101
 a(1)=     4.907 +-  0.163
 a(2)=     0.875 +-  0.143
 a(3)=     0.083 +-  0.122
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c), r_c=0.95
 a(0)=     5.1914
 a(1)=     1.1800
 a(2)=     0.2280
 a(3)=     0.0546
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set