Abstract: A compact objective lens is disclosed which is particularly suitable for infrared optical systems. The lens features a simple design with only two lens elements, namely a first lens element receiving incident radiation and having front and rear surfaces, and a second lens element receiving incident radiation from the first element and having front and rear surfaces. The lens forms an image of a scene on a focal plane. At least three of the four surfaces of the elements are aspheric surfaces. The lens has an f-number less than about 2, a field-of-view less than about 30 degrees, and an effective focal length less than about 6 inches. The elements are made from a material selected to pass radiation in the infrared band of the electromagnetic spectrum, e.g., germanium. The lens is suitable for use as an objective lens for a long-wave infrared sight for small arms, e.g., rifle or shoulder-launched surface to air missile launching system, i.e.

Abstract: A compact objective lens is disclosed which is particularly suitable for infrared optical systems. The lens features a simple design with only two lens elements, namely a first lens element receiving incident radiation and having front and rear surfaces, and a second lens element receiving incident radiation from the first element and having front and rear surfaces. The lens forms an image of a scene on a focal plane. At least three of the four surfaces of the elements are aspheric surfaces. The lens has an f-number less than about 2, a field-of-view less than about 30 degrees, and an effective focal length less than about 6 inches. The elements are made from a material selected to pass radiation in the infrared band of the electromagnetic spectrum, e.g., germanium. The lens is suitable for use as an objective lens for a long-wave infrared sight for small arms, e.g., rifle or shoulder-launched surface to air missile launching system, i.e.

Abstract: A compact objective lens is disclosed which is particularly suitable for infrared optical systems. The lens features a simple design with only two lens elements, namely a first lens element receiving incident radiation and having front and rear surfaces, and a second lens element receiving incident radiation from the first element and having front and rear surfaces. The lens forms an image of a scene on a focal plane. At least three of the four surfaces of the elements are aspheric surfaces. The lens has an f-number less than about 2, a field-of-view less than about 30 degrees, and an effective focal length less than about 6 inches. The elements are made from a material selected to pass radiation in the infrared band of the electromagnetic spectrum, e.g., germanium. The lens is suitable for use as an objective lens for a long-wave infrared sight for small arms, e.g., rifle or shoulder-launched surface to air missile launching system, i.e.

Abstract: A compact objective lens is disclosed which is particularly suitable for infrared optical systems. The lens features a simple design with only two lens elements, namely a first lens element receiving incident radiation and having front and rear surfaces, and a second lens element receiving incident radiation from the first element and having front and rear surfaces. The lens forms an image of a scene on a focal plane. At least three of the four surfaces of the elements are aspheric surfaces. The lens has an f-number less than about 2, a field-of-view less than about 30 degrees, and an effective focal length less than about 6 inches. The elements are made from a material selected to pass radiation in the infrared band of the electromagnetic spectrum, e.g., germanium. The lens is suitable for use as an objective lens for a long-wave infrared sight for small arms, e.g., rifle or shoulder-launched surface to air missile launching system, i.e.

Abstract: A dual band hyperspectral framing aerial reconnaissance camera includes an objective optical subassembly for receiving incident radiation from a scene external of the vehicle, and a dividing element receiving radiation from the objective optical subassembly. The dividing element directs radiation into a first optical path for imaging in a first band of the spectrum and a separate second optical path for imaging in a second band. A first two-dimensional electro-optical detector in the first path generates a first series of images and a second two-dimensional electro-optical detector in the second optical path generates a second set of imagery. At least one of the first and second electro-optical detectors comprises a hyperspectral imager.

Abstract: A reconnaissance camera is described which has a Cassegrain optical system forming an objective lens that directs radiation to a spectrum-dividing prism. The prism directs radiation in a portion of the electromagnetic spectrum (e.g., visible) into a first optical path having a two-dimensional image-recording medium. Radiation in a second band of the spectrum (e.g., IR or UV) is directed to a second optical path, which has a two-dimensional image-recording medium. A motor system is coupled to a camera housing that encloses the optical elements of the camera and the image recording media. The motor steps the entire camera housing about the roll axis while the image recording media are exposed to generate frames of imagery.

Abstract: A framing aerial reconnaissance camera is described which has a catoptric Cassegrain optical system forming an objective lens that directs radiation to a spectrum-dividing prism. The prism directs radiation in the visible portion of the electromagnetic spectrum into a first optical path having a two-dimensional image-recording medium, such as a charge-coupled device. Radiation in the infrared (IR) band of the spectrum is directed to a second optical path, which has a two-dimensional IR-sensitive image-recording medium, such as an electro-optical IR imaging array. The entire camera is rotated about the aircraft roll axis in a continuous fashion to generate frames of imagery providing panoramic coverage of the scene across the line of flight. While the camera is being rotated about the roll axis, the arrays are exposed to the scene repeatedly to generate a series of two-dimensional frames of imagery.

Abstract: A framing aerial reconnaissance camera is described which has a catoptric Cassegrain optical system forming an objective lens that directs radiation to a spectrum-dividing prism. The prism directs radiation in the visible portion of the electromagnetic spectrum into a first optical path having a two-dimensional image-recording medium, such as a charge-coupled device. Radiation in the infrared (IR) band of the spectrum is directed to a second optical path, which has a two-dimensional IR-sensitive image-recording medium, such as an electro-optical IR imaging array. The entire camera is rotated about the aircraft roll axis in a continuous fashion to generate frames of imagery providing panoramic coverage of the scene across the line of flight. While the camera is being rotated about the roll axis, the arrays are exposed to the scene repeatedly to al generate a series of two-dimensional frames of imagery.

Abstract: A framing aerial reconnaissance camera is described which has a Cassegrain optical system forming an objective lens that directs radiation to a spectrum-dividing prism. The prism directs radiation in the visible portion of the electromagnetic spectrum into a first optical path having a two-dimensional image-recording medium, such as a framing CCD array. Radiation in the infrared (IR) band of the spectrum is directed to a second optical path, which has a two-dimensional framing IR-sensitive image-recording medium. The entire camera can be either rotated about the aircraft roll axis in a continuous fashion or stepped in a series of steps to generate frames of imagery, providing panoramic coverage of the scene across the line of flight in two bands of the spectrum simultaneously.

Abstract: A dual band optical system for a framing aerial reconnaissance camera is described. The camera including at least two two-dimensional image recording media for generating frames of imagery of a scene external of an aerial reconnaissance vehicle carrying the camera. The camera includes a Cassegrain optical system forming an objective lens for the optical system, including a a primary mirror having a central aperture and a secondary mirror. The primary and secondary mirrors are aligned along an objective optical axis. The optical system also includes an azimuth mirror receiving radiation from the secondary mirror. The azimuth mirror is placed between the primary and secondary mirrors. A spectrum-dividing element in the form of a prism receives radiation from the azimuth mirror.

Abstract: A method and retainer assembly for securely retaining a lens in a cell or other holding structure so that the lens does not become displaced when the cell is subject to mechanical shock and vibration. The invention is particularly useful for use in retaining large, heavy optical elements, such as can be found in long focal length aerial reconnaissance camera systems. The method involves the step of seating and centering the lens into the cell. The lens has a peripheral surface having a beveled feature. A first rigid, e.g., metallic, ring having a complementary beveled surface is installed over the peripheral beveled surface of the lens. A second rigid, e.g., metallic, ring is installed over the first ring. A retaining ring is threaded onto the cells such that the retaining ring abuts against the second ring. The retaining ring is tightening onto the cell such that the second ring conforms to the retaining ring while maintaining the alignment of the lens in the cell.

Abstract: An optical sight for a weapon system is upgraded with a retrofit module that provides both gunner sighting at the eyepiece and video transmission of the image the gunner sees to a remote location such as, for example, the helmet display of the commander for the weapon system. The video image may be used for both fire control as well as training of the gunner. The retrofit module is adaptable to most types of sighting systems.