Moduli spaces of framed instanton bundles on CP3 and twistor sections of moduli spaces of instantons on C2

We show that the moduli space M of framed instanton bundles on CP3 is isomorphic (as a complex manifold) to a subvariety in the moduli of rational curves of the twistor space of the moduli space of framed instantons on R4. We then use this characterization to prove that M is equipped with a torsion-free affine connection with holonomy in Sp(2n,C).