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A high contrast coronagraph is expected to provide one of the promising waysto directly observe extra-solar planets. We present the newest results of ourlaboratory experiment investigating "rigid" coronagraph with a binary shapedcheckerboard pupil mask, which should offer a highly stable solution fortelescopes without adaptive optics (AO) for wavefront correction in spacemissions. The primary aim of this work was to study the stability of thecoronagraph, and to demonstrate its performance without adaptive wavefrontcorrection. Estimation of both the raw contrast and the gain of the pointspread function (PSF) subtraction were needed. The limiting factor of thecontrast was also important. A binary shaped pupil mask of a checkerboard typehas been designed. The mask, consisting of an aluminum film on a glasssubstrate, was manufactured using nano-fabrication techniques with electronbeam lithography. Careful evaluation of coronagraphic performance, includingPSF subtraction, was carried out in air using the developed mask. A contrast of$6.7 \times 10^{-8}$ was achieved for the raw coronagraphic image by arealaveraging of all of the observed dark regions. Following PSF subtraction, thecontrast reached $6.8 \times 10^{-9}$. Speckles were a major limiting factorthroughout the dark regions of both the raw image and the PSF subtracted image.A rigid coronagraph with PSF subtraction without AO is a useful method toachieve high contrast observations. Applications of a rigid coronagraph to aSpace Infrared telescope for Cosmology and Astrophysics (SPICA) and otherplatforms are discussed.

High contrast experiment of an AO-free coronagraph with a checkerboard pupil mask