First images on the sky from a hyper telescope

Abstract

We show star images obtained with a miniature "densified pupil imaging interferometer" also called a hyper-telescope. The formation of such images violates a "golden rule of imaging interferometers" which appeared to forbid the use of interferometric arrangements differing from a Fizeau interferometer. These produce useless images when the sub-apertures spacing is much wider than their size, owing to diffraction through the sub-apertures. The hyper-telescope arrangement solves these problems opening the way towards multi-kilometer imaging arrays in space. We experimentally obtain an intensity gain of 24 ± 3× when a densified-pupil interferometer is compared to an equivalent Fizeau-type interferometer and show images of the double star α Gem. The initial results presented confirm the possibility of directly obtaining high resolution and high dynamic range images in the recombined focal plane of a large interferometer if enough elements are used.