TECHNICAL FIELD

This disclosure pertains to an afocal attachment for a telescope.

BACKGROUND

Afocal adapters are optical devices usually made of two or more lenses that receive and expand or contract waves of electromagnetic radiation entering a lens that follows the afocal adaptor. An afocal adaptor does not have a focal point but resizes received images. Another name for afocal adapters is “beam expanders.” A beam expander can expand or contract the incoming beam.

SUMMARY

The disclosure relates to an afocal attachment for a telescope. A telescope as disclosed herein can be considered to be optical or digital and refer to, for example, a weapon scope, binocular set, camera lens, or other optical device. The details of one or more implementations of the subject matter of this specification are set forth in the following description and the accompanying drawings to enable a person of ordinary skill in the art to practice the disclosed subject matter. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

In an implementation, an afocal attachment, includes an optical channel including a receiving end and a transmitting end which defines a first optical axis. The afocal attachment further includes a first lens positioned at the receiving end of the optical channel and a second lens positioned at the transmitting end of the optical channel, an inner housing which includes an inner surface that defines a receptacle for the second lens. The inner housing can enclose a portion of the optical channel. The afocal attachment also includes an outer housing which encloses at least a portion of the inner housing, and is movably attached to the inner housing, to permit adjustment of the optical axis relative to the afocal attachment. A mounting connection is provided for mounting the afocal attachment in a position in front of an objective lens of an optical instrument (e.g., a telescope, or rifle scope) where the optical instrument defines a second optical axis. The mounting position can be such that the first optical axis and the second optical axis can be aligned. The afocal attachment further includes at least one adjustment mechanism in contact with the inner housing, which permits precision adjustment of the alignment of the first optical axis.

Implementations can optionally include one or more of the following features.

In some instances, the mounting connection is a friction mount which includes a retention band and a tightening screw. The mounting connection can be affixed to either the inner or the outer housing.

In some instances, the mounting connection is a thread and screw type connection, and the afocal attachment is threaded directly onto the optical instrument. The mounting connection can be affixed to either the inner or the outer housing.

In some instances, the mounting connection is a bayonet mount.

In some instances, the mounting connection includes a mounting block attached to the outer housing and configured to be mounted to a Picatinny rail that is shared by the optical instrument. Additionally the mounting block can permit a height above the rail of the afocal attachment to be adjusted.

In some instances, the magnification produced by the afocal attachment is adjustable. The magnification can be adjusted by translating a third lens, supported by an intermediate housing, which is positioned between the first lens and the second lens, and translatable along the optical axis.

In some instances, the afocal attachment includes a primary reflector and a secondary reflector, and radiation entering the afocal attachment reflects from the primary reflector to the secondary reflector.

In some instances, the afocal attachment includes a digital optics package located in a central dead zone of the first lens and including: at least one aperture for receiving electromagnetic radiation, a processing device to transform electromagnetic radiation into data, and a digital optics projector configured to project an overlay image generated based on the data through the second lens in addition to the image provided by the optical channel. The digital optics package can include a night vision optical system, an infrared optical system, a laser rangefinder, or any combination thereof.

The details of one or more implementations of the subject matter of this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

