NGC5139 (omega Cen)
 8 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)=    21.055 +-  0.166
 a(1)=     5.369 +-  0.265
 a(2)=     1.256 +-  0.216
 a(3)=     0.129 +-  0.221
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c)^2, r_c=2.24
 a(0)=     6.2789
 a(1)=     1.0177
 a(2)=     0.4424
 a(3)=     0.1621
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set