There are provided a reticle, a reticle unit, and an optical apparatus, such as a rifle scope, each having a novel configuration that allows formation of a desired pattern. In a reticle 30A.sub.1 on which a pattern that serves as an indicator when an object under observation is visually recognized is formed, the pattern is formed of protruding sections 33a and 33b provided on a pattern formation surface 31a of a plate-shaped optical member 31. The protruding sections 33a and 33b are each formed of a plurality of protruding ridges 133 (structural elements) extending in the lengthwise direction of a line that forms the pattern in parallel to the widthwise direction of the line. The protruding ridges 133 each have an inclining surface 140 inclining with respect to the optical path of an observation optical path, and the inclination angle of the inclining surface with respect to the optical axis Z is so set at an angle that causes light incident via an objective lens to be deflected to exit out of the observation optical path.

Systems of the present disclosure may include one or more of an optical overlay device, which may include one or more of an imaging optic to receive incoming light from a scene, and project at least a portion of the incoming light onto an imaging sensor; an imaging sensor to transduce into image data the light projected onto it by the imaging optic; a processing engine electrically coupled with a non-transitory computer readable medium having machine readable instructions stored thereon, which, when executed by the processing engine, cause the system to: generate a scaled overlay image based on the image data and a magnification parameter; a display device configured to project the scaled overlay image through a display optic toward a portion of a beam-combiner; a coupling mechanism to enable releasable attachment of the optical overlay device with a primary viewing device.

An optical apparatus includes an eye width adjustment mechanism that includes a first connecting member configured to connect a connecting portion of the right eyepiece unit on one side of a reference plane and a connecting portion of the left eyepiece unit on the other side of the reference plane to each other where the reference plane is a plane including the rotation center axes of the right and left eyepiece units, and a second connecting member configured to connect the connecting portion of the right eyepiece unit on the other side of the reference plane and the connecting portion of the left eyepiece unit on the one side of the reference plane.

Intensity values of electromagnetic radiation from an object to be imaged are received from an array of detectors. The array of detectors includes one or more pairs of detectors arranged as antisymmetric pairs of detectors. A Fourier transform of an image of the object is determined by correlating fluctuations of the intensity values for each antisymmetric pair of detectors. An inverse of the Fourier transform is determined, and an image of the object is generated from the inverse Fourier transform. The Fourier transform of the mean intensity pattern across the array of detectors may also be used to determine when the array is properly oriented to separate the image and mirror image.

An apparatus includes a first light source to produce a first reference light, a first pair of arrayed waveguide gratings (AWGs) to demultiplex a first optical signal and the first reference light, respectively, into multiple first signal beams and multiple first reference beams. A first heterodyne optical detector can mix the multiple first signal beams and the multiple first reference beams to generate first quadrature optical signals. A first pair of photo-detectors can convert the first quadrature optical signals to first in-phase (I) and quadrature (Q) electrical signals. The apparatus is implemented as a photonic integrated circuit (PIC) incorporating the first pair of AWGs, the first heterodyne optical detector and the first pair of photo-detectors.

An apparatus includes a first light source to produce a first reference light, a first pair of arrayed waveguide gratings (AWGs) to demultiplex a first optical signal and the first reference light, respectively, into multiple first signal beams and multiple first reference beams. A first heterodyne optical detector can mix the multiple first signal beams and the multiple first reference beams to generate first quadrature optical signals. A first pair of photo-detectors can convert the first quadrature optical signals to first in-phase (I) and quadrature (Q) electrical signals. The apparatus is implemented as a photonic integrated circuit (PIC) incorporating the first pair of AWGs, the first heterodyne optical detector and the first pair of photo-detectors.

Disclosed is an optical scope including an objective lens, an eyepiece lens, and a reticle, wherein a field lens having negative power is disposed in at least one of a front and a back of the reticle disposed on an image formation surface of the objective lens to increase eye-relief.

Disclosed is an optical scope including an objective lens, an eyepiece lens, and a reticle, wherein a field lens having negative power is disposed in at least one of a front and a back of the reticle disposed on an image formation surface of the objective lens to increase eye-relief.

A multi-order diffractive Fresnel lens (MOD-DFL) that is suitable for use in a space telescope for studying transiting earth-like planets of distant stars is provided. The MOD-DFL may comprise a MOD-DFL array comprising a plurality of MOD-DFL segments that are secured to a mounting surface of a deployment device, such as a balloon, for example, in a preselected arrangement to form the MOD-DFL. An array telescope may be formed of an array of deployment devices, such as an array of balloons, for example, each having a MOD-DFL secured to a mounting surface of the respective deployment device, an optics system disposed inside of the respective deployment device, and a camera disposed inside of the respective deployment device. Each MOD-DFL comprises a plurality of MOD-DFL segments arranged in a preselected arrangement to form the respective MOD-DFL.

Multiple telescopes of a telescope array are rigidly aligned at predetermined relative orientations to simultaneously image corresponding predesignated celestial objects. Detection of light from the celestial objects collected by the telescopes enables calculation or estimation of orientation of the telescope array with respect to the celestial sphere. That orientation, in combination with a planetary nadir direction, enables estimation or calculation of position of the telescope array relative to a planetary surface. The nadir can be measured by dropping a probe particle through an evacuated chamber onto or through a two-dimensional sensor.