Kepler–harmonic radial duality
= Kepler–harmonic radial duality
{c}
{title2=$r=(\bar E/GM)\bar r^2$}
Taking $\bar E=GM\,r/q^2>0$ in a <radial orbit time transformation> gives $r=(\bar E/GM)q^2$ and $\bar\Phi(q)=-E(\bar E/GM)^2q^2$. Bound <Kepler orbits> with $E<0$ map to a confining <harmonic oscillator>; positive <energy> maps to an inverted oscillator. Full angular reconstruction halves the original orbital angle.