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US 7,719,761 B2Granted
Peripheral filtering star tracker telescope
AssigneeThe Aerospace Corporation
InventorKenneth H. Lau
Life of this patent
Estimating the term…
Abstract
A filter or lens for a star-tracking telescope includes a clear center portion and an attenuating peripheral portion. The peripheral portion attenuates off-axis images through any radial line extending from a center of the filter or lens to a circumference edge of the filter or lens. The attenuation is for passing on-axis images with high signal to noise ratios, for attenuating off-axis images, and for attenuating but not completely blocking the off-axis images. The telescope with such a filter or lens is well suited for improved star tracking systems, and well suited for reducing off-axis glare in handheld optical apparatus such as binoculars, telescopes, cameras, and eyeglasses.
Claims22
A system for electronic imaging comprising,
- an on-axis object and an off-axis object,
- a filter arranged to concurrently pass an on-axis image from the on-axis object and an off-axis image from the off-axis object
- an outer portion of the filter adapted to attenuate the off-axis image of the off-axis object, the off-axis image being a peripheral image passing through the outer portion,
- an inner portion of the filter adapted to pass the on-axis image of the on-axis object,
- the inner portion of the filter adapted to attenuate the on-axis image lesser than the attenuation of the off-axis image passing through the outer portion,
- an optical system having one or more first optical elements optically opposed and physically remote from a focal plane,
- the filter being one of the first optical elements,
- an electronic photographic imaging sensor having a surface illuminated by a substantially focused image of at least one of the objects, and
- information sufficient to reproduce a photograph of at least one of the images being available from the imaging sensor.
6 more elements
A telescope comprising,
- an on-axis object and an off-axis object,
- an electronic photographic imaging sensor arranged to electronically image an on-axis image of the on-axis object and an off-axis image of the off-axis object,
- the on-axis object being a first celestial body having a first brightness,
- the off-axis object being a second celestial body having a second brightness that is greater than the first brightness,
- a filter comprising an outer portion adapted to attenuate the off-axis image of the off-axis object,
- the off-axis image being a peripheral image arranged to pass through the outer portion,
- the filter further comprising an inner portion adapted to pass the on-axis image of the on-axis object,
- the inner portion adapted to attenuate the on-axis image lesser than the attenuation of the off-axis image passing through the outer portion, and
- information sufficient to reproduce a photograph of the on-axis image being available from the imaging sensor.
6 more elements
An electronic imaging system comprising,
- an optical filter having inner and outer portions,
- an on-axis object arranged to illuminate an electronic photographic imaging sensor with a filtered on-axis image,
- an off-axis object arranged to illuminate the imaging sensor with a filtered off-axis image,
- the brightness of the off-axis image being greater than that of the on-axis image when the images arrive at the filter,
- an optical system having one or more first optical elements optically opposed and physically remote from a focal plane end,
- the filter being a first optical element,
- a tubular shade extending substantially between the first optical elements and the imaging sensor,
- the tubular shade having internal baffles adapted to block light from selected off-axis objects,
- the outer portion adapted to attenuate an off-axis image of the off-axis object, the off-axis image being a peripheral image passing through the outer portion,
- the inner portion adapted to pass an on-axis image of the on-axis object, the inner portion attenuating the on-axis image lesser than the attenuation of the off-axis image passing through the outer portion, and
- information sufficient to reproduce a photograph of the on-axis image being available from the imaging sensor.
8 more elements
A method of electronic imaging comprising the steps of,
- providing an optical filter having inner and outer portions,
- providing an on-axis object and an-off axis object,
- illuminating an electronic photographic imaging sensor with filtered light from the on-axis object,
- illuminating the imaging sensor with filtered light from the off-axis object,
- selecting the objects such that the brightness of the off-axis image is greater than that of the on-axis image when they arrive at the filter,
- providing one or more first optical elements including the filter,
- arranging the first optical elements to be optically opposed and physically remote from a focal plane end,
- locating a tubular shade substantially between the first optical elements and the imaging sensor,
- locating baffles on an interior of the tubular shade to block light from selected off-axis objects,
- adapting the outer portion to attenuate an off-axis image of the off-axis object, the off-axis image being a peripheral image passing through the outer portion,
- adapting the inner portion to pass an on-axis image of the on-axis object, the inner portion attenuating the on-axis image lesser than the attenuation of the off-axis image passing through the outer portion, and
- generating information sufficient to reproduce a photograph of the on-axis image from the imaging sensor.
9 more elements
Dependencies are inferred from the claim text.