We have recently deployed a four-quadrant phase-mask coronagraph behind an un-obscured, circular, off-axis section of the Palomar 200-inch telescope To obtain veiy good wave-front correction across the 1.5 m subaperture, our relay optics reimage the sub-aperture onto the adaptive optics system's deformable mirror This approach combines the advantages of low diffraction from obscuring elements, due to the off-axis aperture, with high wavefront correction, due to the magnification of the pupil, and high stellar rejection, due to the phase mask coronagraph. Our initial on-sky results include Strehl ratios exceeding 90%, peak stellar rejections of >100:l, and an improvement in contrast of 235:1 on a binary of separation 2X/D.
展开▼
