Cohomology of the moduli space of SO(n)-instantons with instanton number 1

Let M(1,SO(n)) denote the moduli space of based gauge equivalence classes of SO(n)-instantons over S4 with instanton number 1. In this paper, using a description of M(1,SO(n)) in terms of a homogeneous space, we determine the mod 2 cohomology ring with squaring operations and the integral cohomology group of M(1,SO(n)).