The two Rayleigh–Ritz discriminant degrees of the standard rational normal curve

For the standard unweighted rational normal curve of degree $d \ge 2$, we prove
that the reduced isotropic part of its Rayleigh–Ritz discriminant has degree
$2d$ and its reduced nonisotropic part has degree $6(d-1)$. The argument
identifies the critical correspondence with a binary Wronskian, establishes the
irreducibility of the nonisotropic image, and proves that every component
occurs with multiplicity one in the binary discriminant. It includes the
smallest degree, the points at infinity, and the kernel of the map from
symmetric matrices to binary numerators.