NGC6284       c
 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)=    18.650 +-  0.108
 a(1)=     3.239 +-  0.206
 a(2)=     1.071 +-  0.153
 a(3)=     0.130 +-  0.148
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=r
 a(0)=     7.1231
 a(1)=     0.4713
 a(2)=     0.6638
 a(3)=     0.2705
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set