High contrast experiment of an AO-free coronagraph with a checkerboard pupil mask K. Enya, L. Abe, S. Tanaka, T. Nakagawa, K. Haze, T. Sato and T. Wakayama A&A, 480 3 (2008) 899-903 Published online: 25 January 2008 DOI: 10.1051/0004-6361:20078627