NGC6352
 3 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)=    19.766 +-  0.215
 a(1)=     1.453 +-  0.316
 a(2)=    -0.282 +-  0.258
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)=     8.1470
 a(1)=     4.0500
 a(2)=    -1.3884
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set