NGC6341 (M92)
 6 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)=    20.529 +-  0.141
 a(1)=     6.016 +-  0.266
 a(2)=     1.183 +-  0.197
 a(3)=     0.237 +-  0.200
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c), r_c=1.29
 a(0)=     5.0695
 a(1)=     1.8583
 a(2)=    -0.1675
 a(3)=     0.1478
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set