NGC6723
12 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)=    21.009 +-  0.175
 a(1)=     3.655 +-  0.281
 a(2)=     0.752 +-  0.165
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c), r_c=1.76
 a(0)=     7.6019
 a(1)=     0.5408
 a(2)=     1.0576
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set