The Four‐Quadrant Phase‐Mask Coronagraph. I. Principle

We describe a new type of coronagraph, based on the principle of a phase mask as proposed by Roddier and Roddier a few years ago but using an original mask design found by one of us (D. R.), a four‐quadrant binary phase mask (0, π) covering the full field of view at the focal plane. The mutually des... View More