AM1
 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)=     1.983 +-  0.183
 a(1)=     2.555 +-  0.280
 a(2)=     0.501 +-  0.255
 a(3)=     0.169 +-  0.244
Power-of-x coeffients a(0)+a(1)x+a(2)x^2+..., where x=1+(r/r_c)^2, r=0.92
 a(0)=    -1.2485
 a(1)=     1.5930
 a(2)=    -0.6058
 a(3)=     0.3005
log r(arcsec)   mu_V    mu_V(fitted)  residual   weight  data set