US 5,291,333 A · Alignment system for a segmented telescope

Abstract

A new coronagraph sufficiently increases the contrast ratio between the infrared image of a nonsolar star and a possible orbiting nonsolar planet to make imaging of such a planet possible. The coronagraph is used with an infrared telescope system having a square objective or aperture. Unwanted stellar irradiance is diffracted orthogonally by the square telescope aperture or objective so that a coronagraph apodizer in the first focal plane in the shape of crossed arms, and a coronagraph Lyot stop in the pupil plane with a square opening, stop most of the on-axis direct and diffracted stellar energy while allowing most of the planet irradiance to pass through the coronagraph. The discarded light reflected from the back of the apodizer can be used to provide information concerning piston and tilt error of individual segments of a segmented telescope so that an array of correcting piston-tilt mirrors can be controlled to align the telescope.

Claims4

Dependent claims

An alignment system for correcting alignment errors for a segmented telescope, wherein the segmented telescope includes a coronagraph, and wherein the coronagraph includes an apodizer, comprising:

(a) an array of telescope primary segments;
(b) an array of piston-tilt mirrors, wherein each piston-tilt mirror corresponds to a telescope primary segment, and wherein each piston-tilt mirror is in a conjugate image plane of its corresponding telescope primary segment;
(c) an array of lenses, wherein each lens corresponds to a piston-tilt mirror and to that piston-tilt mirror's corresponding telescope primary segment, and wherein each lens of the array of lenses, for light rays reflected from the back of the apodizer, is in a conjugate image plane of both its corresponding telescope primary segment and of its corresponding piston-tilt mirror;
(d) position sensor means for determining the relative positions of each focal point of the light rays focused by each lens of the array of lenses;
and,
(e) computer means for reading the relative focal point positions, for determining needed piston and tilt corrections to each of the piston-tilt mirrors so that, in combination, they project a light wavefront known to be the same as those of light rays impinging on the array of primary segments, and for applying those piston and tilt corrections to the array of piston-tilt mirrors to effect that correction.

3 more elements

Dependencies are inferred from the claim text.

Alignment system for a segmented telescope

Life of this patent

Alignment system for a segmented telescope

Life of this patent

Abstract

Claims4