Compactification of $M_{{\bf P}_3}(0,2)$ and Poncelet pairs of conics.

Let M(0, 2) denote the quasi-projective variety of isomorphism classes of stable rank 2 vector bundles on P 3 (C) with C 1 =0 and C 2 =2 . In this paper we study a natural (irreducible) compactification of M(0, 2) and describe explicitly the sheaves on P 3 which occur in the closure of M(0, 2) in the moduli space of semi-stable sheaves on P 3 with c 1 = 0, c 2 =2 and c 3 =0.