Patent Description:
Gun-sights include optical gun-sights which are suitable for daylight use, and thermal gun-sights suitable for use in darkness or low light conditions. Optical gun-sights, such as, but not limited to, iron gun-sights, telescopic, day and night gun-sights and reflex gun-sights are characterized in that the user aligns the gun's barrel with the target by viewing the target through the optical gun-sight.

Gun-sight zeroing approaches can be broken into live gun-sight zeroing and gun-sight dry zeroing. Live gun-sight zeroing involves actual firing and correction of offsets by adjustments made in the position of the gun-sight with respect to the gun's barrel. Live gun-sight zeroing is considered limiting because it requires (i) a firing zone; and (ii) light conditions which match the properties of the gun-sight being zeroed. Thus, day operated gun-sights cannot be zeroed during night time and vice-versa.

Dry zeroing facilitates calibration of the sight without actual firing of the weapon. and ensures that the point of aim and the point of impact is the same for a given range.

Several systems for gun-bore sighting under various light conditions are known, e.g.,.

<CIT> appears to disclose, "A sight system is provided that includes an optical mode providing an optical image of a field of view and a video display mode providing video of the field of view acquired by an image sensor. The sight system can include optical components configured to present the field of view to the image sensor and to present substantially the field of view to a user through an eyepiece coupled to the sight system. The sight system can include a display configured to display to the user, through the eyepiece, video of the field of view acquired by the image sensor. The sight system can include a user interface feature configured to change from the optical mode to the video display mode when actuated by the user. Thus, the sight system can be configured to provide bore-sighted optical and video data to the user.

<CIT> appears to disclose, "An imaging system includes a focal plane array including an array of pixels. An isothermal diaphragm covers a first portion of the pixels along a periphery of the array and exposing an imaging portion of the pixels. A controller is operatively connected to the focal plane array to read sensor data from the focal plane array, wherein the sensor data includes image data from the imaging portion of the pixels and non-uniformity data from the first portion of the pixels. The controller is operatively connected to the focal plane array to enhance the image data based on the non-uniformity data.

<CIT> appears to disclose, "Day and night sighting apparatus <NUM> comprising a day sighting apparatus, consisting of a periscope <NUM> and a aiming head <NUM>, as well as with a thermal-imager <NUM>, a cathode-ray tube <NUM> for reproducing the thermal image converted into visible frequencies. The necessary axis harmonisation of the day sighting apparatus and the thermal imager of known like apparatus is abolished in that in the apparatus <NUM> a reticle <NUM> is generated electronically and is displayed on screen <NUM> of the cathode-ray tube <NUM>. Thus, the reticle <NUM> can be used not only in an eyepiece <NUM>, but also by a coupled-up automatic target detection or tracking apparatus.

<CIT> appears to disclose, "A fused thermal and a direct view aiming sight includes an optical gun sight, a thermal sight, and a beam combiner. The optical sight generates a direct view image of an aiming point or reticle superimposed on a target scene. The thermal sight generates a monochromic thermal image of the target scene. The combiner is positioned behind a <NUM>× non-magnified optical sight and the thermal sight and in front of an exit pupil of the thermal sight. The combiner is positioned right behind the intermediate image plane of a magnified optical sight between an objective lens and an eyepiece. The combiner passes the direct view image and reflects the thermal image to the exit pupil to fuse the thermal image onto the direct view image for an operator to see at the exit pupil as a combined thermal and direct view optical image of the target scene together with the aiming reticle.

<CIT> appears to disclose, "A sighted device has a sight that includes an objective lens lying on an optical axis of the sight so that an input beam is coincident with the optical axis, an eyepiece lens lying on the optical axis, an imaging detector having a detector output signal, a signal processor that receives the detector output signal from the imaging detector, modifies the detector output signal, and has a processor output signal, and a video display projector that receives the processor output signal and has a video display projector output. An optical beam splitter lies on the optical axis. The beam splitter allows a first split subbeam of the input beam to pass to the eyepiece lens and reflects a second split subbeam of the input beam to the imaging detector. An optical mixer mixes the first split subbeam and the video display projector output prior to the first split subbeam passing through the eyepiece lens.

<CIT> appears to dislcose, "An optical system for a periscope-like sighting device is proposed for the localization, tracking and measurement of a target and comprises a plurality of optical elements as well as a laser range-finder essentially comprising transmitter and receiver portions. In this optical system, the visible and invisible radiation mutually parallelly incident upon a main mirror rotatable about a first axis and pivotable about a second axis is reflected to a first deflection prism. The first deflection prism deflects the radiation at substantially right angles through an objective lens to a first beam-splitter. The first beam-splitter deflects the invisible laser radiation to the receiver portion and transmits the visible radiation to a second beam-splitter and thence to a second deflection prism and an ocular. For achieving a view of the field of observation or a tracking of the target, or both, a television camera can be arranged on the side of the housing of the sighting device.

<CIT> appears to disclose, "A system for aiming a projectile weapon includes a telescopic sight for use with a second sighting device, such as a reflex sight or other non-magnifying sight. The telescopic sight has an eye point spaced apart rearwardly from its eyepiece and positioned at a vertical plane containing a line of initial trajectory of the weapon to which the aiming system is mounted so that a line parallel to the line of initial trajectory does not intersect the eyepiece. The location of the eye point facilitates concurrent use of a second sighting device at a normal mounting height and viewable past the eyepiece, thereby allowing the viewer to change views between the telescopic sight and the second sighting device with little eye movement and essentially no head movement.

<CIT> appears to disclose, "A boresight collimating device using a novel way of achieving multiple source illumination of the pin hole/reticule using one moving part, a rotating elliptical mirror, while maintaining precision alignment of the device is disclosed".

<CIT> appears to disclose, "A test target for thermal and similar rifle sights including a target, comating lens in a housing with a mandrel type boresighting attachment".

According to an aspect of the present invention, there is provided a zeroing assembly for a gun-sight comprising: a zeroing target, a dual band lens; and a switching mechanism configured to reversibly move the dual band lens from a first position to a second position along its optical axis, thereby switching the zeroing assembly from a first sighting configuration wherein light in a first band from said zeroing target is focused on a gun sight to a second sighting configuration wherein light in a second band from said zeroing target is focused on said gun sight.

According to some embodiments of the invention, the first configuration focuses visible light coming from the zeroing target through the gun-sight and the second configuration focuses infrared light coming from the zeroing target through the gun-sight.

According to some embodiments of the invention, the zeroing target includes a reticle.

According to some embodiments of the invention, the reticle is made of a material that is opaque to visible light and a good conductor.

According to some embodiments of the invention, the reticle is made of metal.

According to some embodiments of the invention, the reticle includes at least one of a grid and coordinates engraved thereon.

According to some embodiments of the invention, the lens is composed of a material that is transparent both to visible light and to infrared light.

According to some embodiments of the invention, the lens is composed of Zinc Selenide.

According to some embodiments of the invention, the first sighting configuration is an optical sighting configuration.

According to some embodiments of the invention, the zeroing assembly further includes a visible light illumination source located between the zeroing target and the dual band focusing assembly.

According to some embodiments of the invention, the illumination source is controlled by a controller.

According to some embodiments of the invention, the second sighting configuration is a thermal sighting configuration.

According to some embodiments of the invention, the zeroing assembly further includes at least one thermistor.

According to some embodiments of the invention, the zeroing assembly further includes a thermal cooler.

According to some embodiments of the invention, the thermal cooler includes a thermoelectric cooler (TEC).

According to some embodiments of the invention, the thermal cooler cools a portion of the target.

According to some embodiments of the invention, a thermal cooler cools the reticle.

According to some embodiments of the invention, the zeroing assembly further includes a controller, wherein the controller is configured to activate or deactivate at least one thermal cooler based on a signal from at least one thermistor.

According to an aspect of some embodiments of the invention, there is provided a method for changing a band of an optical system for dual band bore sighting, the method including: providing a focusing assembly in a first configuration for use in a first band, the focusing assembly in the first configuration focusing light in a first band from a target onto a gun sight; and; reversibly switching the focusing assembly from the first configuration to a second configuration wherein the focusing assembly focuses light in a second band from the target onto the gun sight; wherein the optical system includes a dual band lens and wherein the reversible switching includes moving the dual band lens from a first position in a to a second position along an optical axis of the optical system.

According to some embodiments of the invention, the first position and the second position are predetermined.

According to some embodiments of the invention, the method where the optical system further includes a switching mechanism, and the switching includes reversibly toggling the switching system between two predetermined states.

According to some embodiments of the invention, the first configuration is an optical sighting configuration.

According to some embodiments of the invention, the second configuration is a thermal sighting configuration.

According to some embodiments of the invention, in the first configuration a first illuminations source in the first band is designated and further including a controller designating a second illumination source in the second band.

According to some embodiments of the invention, the controller is configured to synchronize the switching to designating of an illumination source.

According to some embodiments of the invention, the system includes a first illumination source in the first band and a second illumination source in the second band and further including the controller designating the second illumination source in response to the switching.

According to some embodiments of the invention, the controller is configured to activate or at least one thermal cooler in response to the switching.

According to some embodiments of the invention, when the system is in the second configuration, the controller is configured to activate a thermal cooler in response to a signal from at least one thermistor.

According to some embodiments of the invention, for optical sighting a visible source is designated, and a thermal cooler is deactivated.

According to some embodiments of the invention, for thermal sighting, a visible illumination source is deactivated, and a thermal cooler is activated.

The present invention in some embodiments, thereof relates to a sight dry zeroing assembly (e.g., a bore sighting assembly) and, more particularly, but not exclusively, to a gun-sight dry zeroing assembly which is suitable for dry zeroing of gun-sights in multiple light bands. For example, a visible light sight and low light gun-sights. For example, the an infrared and/or thermal sight and a visible light sight.

A gun-sight assembly may be used for many devices including weapons such as small arms, an infantry weapon, a rifle, an assault rifle etc. For the sake of the following disclosure unless specifically stated otherwise, the term "gun-sight" may refer to a sight for any weapon and/or of another device.

According to the present invention the gun-sight assembly includes a dual band focusing assembly. The dual band focusing assembly includes one or more lenses. The dual band focusing assembly includes two or more configurations. The dual band focusing assembly includes a switching mechanism to facilitate reversibly switching the system between two or more configurations. Optionally, the dual band focusing assembly may include an optical gun-sight configuration. Optionally, the dual band focusing assembly may include a thermal gun-sight configuration. For example, a toggle mechanism may facilitate switching between a first configuration, such as an optical gun-sight configuration, and a second configuration, such as a thermal gun-sight configuration, and vice versa.

According to the invention, the system will include a dual band lens. For example, the dual band lens may be transparent (e.g., greater that <NUM>% transmission and/or greater that <NUM>% transmission and/or greater than <NUM>% transmission in both the visible spectrum (for example, from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM>) and the Infrared (IR) spectrum (from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM> and/or from <NUM> to <NUM>). According to the invention, the lens may be changed between a first predetermined position which focuses visible light from the target to the gunsight and a second position that focusses infrared light.

In some embodiments, the system may include a dual band target (e.g., a background, an illumination source and/or a reticle). For example, the background and/or reticle may have markings that are discernable under reflected visible illumination and/or are configured to be heated or cooled to become visible in the infrared band. For example, the background and/or reticle may be made of metal (and/or another material highly conductive to heat and/or have features engraved therein.

In some embodiments, a system may include multiple illumination systems. For example, there may be a visible light source, e.g., to illuminated a background and/or a reticle in the visible spectrum. For example, there may be an infrared illumination system. For example, the infrared illumination system may include a heater and/or a cooling system (e.g., a Thermal cooling device (a TAC) which may include a Thermal Electric cooler (a TEC)).

In some embodiments the various systems may be integrated and/or synchronized. For example, when working in the visible spectrum, the focusing system may be put into a visible spectrum configuration and/or a visible light illumination system may be activated and/or designated. For example, when working in the infrared spectrum, the focusing system may be put into an infrared configuration and/or an infrared illumination system may be activated and/or designated.

In some embodiments, a zeroing target may include a reticle, a grid, etc. that may be configured for viewing in both the thermal and visible spectrums. In some embodiments, the reticle may be positioned in front of a thermal cooler. Optionally, the cooler may be controlled by a controller, e.g., an electronic circuit board (CPU). In some embodiments, the zeroing target may include two or more temperature sensors. Optionally, the temperature sensors may be positioned on one or more areas of the zeroing target and/or may measure and/or update the temperature values. In some embodiments, the CPU in the electronic board may facilitate preserving a sufficient temperature difference between the reticle and the background in order that the zeroing target will be visible through the thermal gun-sight, e.g., by use of one or more thermal coolers (TAC).

In some embodiments, the lens may be made from, but is not limited to, ZiSe (Zinc Selenide). In some embodiments, the zeroing target may be illuminated by a visible light source. Optionally, the light source may be positioned behind the reticle. Alternatively, and/or additionally, the light chamber may be positioned in front of the reticle. Optionally, the light chamber may include, but is not limited to, an LED. The light chamber optionally generates the appropriate light color/s for the various types of gun-sight. In some embodiments, the reticle may be made of stainless steel. Optionally, a grid and/or coordinates may be engraved thereon.

<FIG> is a schematic view of a system, in accordance with an embodiment of the current invention. For example, gun-sight system <NUM> may include a user interface <NUM>. For example, the user interface may include a toggle to switch the system between preset modes (for example, an IR mode and a visible light mode). Optionally the system includes a power source <NUM> connected to a controller <NUM>. In some embodiments, in a visible light mode, the controller <NUM> may set a focusing assembly <NUM> into a visible focusing mode (e.g., wherein visible light from a reticle <NUM> is focused on a sight) and/or designate a visible light source <NUM> that illuminates the reticle <NUM> with visible light when system is activated. In some embodiments, in an IR mode, the controller <NUM> may set a focusing assembly <NUM> into an IR focusing mode (e.g., wherein IR light from a reticle <NUM> is focused on a sight) and/or designate a heat sink (e.g., thermal cooler <NUM>, <NUM>) that cools the reticle <NUM> and/or a reticle when the system is activated so that the reticle will be recognizable against the background in by an IR detector. Alternatively or additionally, the reticle <NUM> and reticle may be heated in the IR mode.

Optionally, the controller <NUM> may be connected to a detector (not shown), which may optionally be cooled or uncooled. The controller <NUM> may be connected to one or more thermal coolers (TAC) <NUM>, <NUM> and one or more thermistors <NUM>, <NUM>. The controller <NUM> may activate and/or deactivate the one or more thermal coolers <NUM>, <NUM> in response to signals from the one or more thermistors <NUM>, <NUM>. The one or more thermistors <NUM>, <NUM> and/or thermal coolers <NUM>, <NUM> may optionally be connected to a reticle <NUM> which may be connected to a focusing assembly <NUM>, which may include one or more lenses.

According to some embodiments, the focusing assembly may be composed of a multi-band material, e.g., Zinc Selenide, etc. Optionally, the focusing assembly may include one or more lenses which may be transparent to the thermal radiation with a wavelength between about <NUM> to about <NUM>.

<FIG> and <FIG> are schematic illustrations of a systems <NUM> and <NUM> in accordance with an embodiment of the current invention. For example, system <NUM> may include a focusing assembly <NUM> focusing visible and infrared (thermal) wavelengths from one or more targets <NUM>. For example, the target <NUM> may include one or more reticles <NUM>. For example, the target <NUM> may include one or more illumination sources. For example, an infrared illumination source may include one or more thermal cooling units (TAC), e.g., having a cold side <NUM> and/or on a hot side <NUM>. The thermal cooling units may optionally be connected to one or more thermistors (not shown). In some embodiments, a relatively warm reticle may be seen in the infrared with respect to a cool background. For example, the background may be cooled and/or the reticle may be at ambient temperature. For example, the cold side <NUM> of the TAC may supply a cold background to a relatively warm reticle which is visible in the infrared. Alternatively or additionally, the reticle may be heated. Alterantively or additionally, the reticle may be cooler than the background. For example, the reticle may be cooled and/or the background heated. Optionally, the thermal cooling units may be connected to a controller <NUM>. Optionally, system <NUM> may include a visible illumination source <NUM>, e.g., an LED for visible illumination, for example, between the focusing assembly <NUM> and/or a background <NUM>. In some embodiments, the visible illumination source <NUM> may be located and/or directed between the focusing assembly <NUM> and the reticle <NUM>, e.g., as in system <NUM> of <FIG>. Alternatively or additionally, the visible illumination source <NUM> may be located and/or directed between the reticle <NUM> and a background <NUM>, e.g., as in system <NUM> of <FIG>. For example, the cool side <NUM> of the TAC may be colored to reflect visible light (e.g., white). In some embodiments, the visible illumination source <NUM> may be connected to and/or controlled by a controller <NUM>.

According to some embodiments, a single zeroing target may be viewable in multiple bands. Alternatively, and/or additionally, the zeroing target may have switchable operation, e.g., when using for optical sighting the LED may be activated and/or the cooling system may be deactivated. For example, a toggle may designate which illumination source responds to an activation command (e.g., the visible lights source is designated to light when a person activates illumination when the system is in a visible mode and/or the heat source/sink is designated to activate in response to a user activating illumination when the system is in an IR mode. Alternatively, and/or additionally, when using the thermal sighting, the LED may be deactivated and/or the cooling system may be activated. Alternatively, and/or additionally, the system may include multiple zeroing targets for different wave bands.

According to some embodiments, the illumination source may be configured to provide a light box behind the reticle e.g., by creating an illuminate light chamber and/or a different temperature background (cold or hot) and/or a different color background (darker and/or lighter). Optionally, the illumination source may be selected with the appropriate light color temperature.

<FIG> and <FIG> are schematic illustrations of a dual band focusing assembly, in accordance with the current invention. For example, a focusing assembly <NUM> may reversibly switch between an optical sighting configuration (e.g., <FIG>) and a thermal sighting configuration (e.g., <FIG>), and vice versa. Focusing assembly <NUM> may include a switching mechanism <NUM>, which may reversibly move the lens from an optical sighting configuration position 302a to a thermal sighting configuration position 302b, and vice versa.

In some embodiments, a user may connect the calibration system to a weapon. For example, aligning the target (e.g., the zeroing target) with the barrel of a gun and/or gun-sight. Optionally, the user may set the system to the desired settings for the selected band. For example, the focal length and/or zeroing target may be selected according to the required bandwidth of the sight. Optionally, there may be a toggle mechanism (e.g., a switchover mechanism) to facilitate switching the system between two or more preset settings and/or configurations (e.g., a first configuration for thermal sighting and a second configuration for optical sighting). Optionally, the user may sight the zeroing target and/or read the position of the crosshair on the zeroing target and/or adjust and/or zero the sight according to the reading.

In some embodiments, the focal length of a lens may vary according to various frequencies (e.g., the focal length may differ between the IR and visible spectrums). Optionally, a switch-over mechanism may be used to set the focal length. For example, by moving the lens (e.g., a dual band lens) closer or further from the target along the optical axis <NUM> of the system. Optionally, the system may include a simple mechanism to switch over the system between fixed states for each frequency band. For example, a switch may move the lens between two configurations, a first configuration where the focal length is suitable for optical sighting, and a second configuration where the focal length is suitable for thermal sighting. For example, the switch may be mechanical and/or electronic and/or electro-mechanical (e.g., with a servo motor). Optionally, to switch between configurations a user may toggle the switch without further adjustment. Optionally, switching between configurations may shift the focusing mechanism. Optionally, switching between configurations may switch the state of the zeroing target. Optionally, switching between configurations may activate and/or deactivate one or more illumination sources and/or one or more cooling units. Alternately or additionally, the position of the target may be changed in different configurations such light from the target is focused onto the sight in the different bands in the different modes.

In some embodiments, the dual band target may be at a different temperature from the background (e.g., for thermal sighting) and/or may be illuminated in the visible spectrum (e.g., for optical sighting). In some embodiments, focal length of the focusing assembly may be set by a two-way switching mechanism (e.g., toggle) which may move the lens between two or more configurations.

<FIG> is a flow chart illustrating calibrating a gun-sight, in accordance with an embodiment of the current invention. For example, in method <NUM>, the gun-sight zeroing system (e.g., dual band target) is positioned <NUM> aligned to the weapon barrel and/or sight. The focal length of the focusing assembly for the selected sight type (e.g., optical, thermal, etc.) is set <NUM>. According to the invention, a multi-band lens may be positioned in one position for one band and/or a second position for the other band. Optionally, an appropriate illumination system is designated (e.g., to be activated when the illumination is desired) and/or activated. For example, a visible light source may be designated in the visible light mode and/or a heat source/sink may be designated in the IR mode. Optionally, the use scenario of different illumination systems may differ. For example, a visible light source (e.g., and LED) may only be activated momentary at the time of a measurement. For example, a heat source/sink may be activated prior to measurements and/or may be run in a controlled mode (e.g., when the system is in the IR mode a temperature may be maintained (optionally in a stand-by mode) even when a measurement is not being made). The device is optionally mounted on the weapon and the current position of the target in the crosshairs relative to the zeroing target in the device is read <NUM>. Correct the alignment of the weapon barrel and/or sight according the reading from the zeroing target <NUM>.

<FIG> is a flow chart of a method of gun-sight dry zeroing, in accordance with an embodiment of the current invention. For example, in method <NUM>, the focusing assembly is set for the selected sighting type (e.g., optical, thermal, etc.) <NUM>. Activate illumination and/or cooling for selected sighting type <NUM>. Optionally, the lighting appropriate illumination system may be activated in a stand-by mode and/or designated for activation when illumination is desired. After setting the bore sighting system for the appropriate sight type, the system is activated. Optionally, with the system activated in the appropriate mode, target coordinates are read through sighting and focusing assembly <NUM> and/or used to calibrated the sight.

<FIG> is a block diagram of a dry gun-sight zeroing system, in accordance with an embodiment of the current invention. For example, in system <NUM>, a dual band focusing assembly <NUM> is connected to a switching mechanism <NUM> and a zeroing target <NUM> and/or an illumination system. For example, when a user toggles the system to a particular mode (e.g., IR and/or visible light) the various subsystems are activated and/or set and/or designated to the appropriate settings. The user then activates the system in the selected mode and/or makes measurements with the appropriate sight.

<FIG> is a flow chart of a method of gun-sight dry zeroing in accordance with an embodiment of the current invention. For example, in method <NUM> position <NUM> a gun-sight zeroing system aligned to the barrel or the sight, zero <NUM> the weapon in a range. Mount <NUM> the system to the weapon and read the current position of the crosshair relative to the zeroing target of the system. Store <NUM> the coordinates of the target. Dismount <NUM> the system from the weapon and insert the system to the barrel. Read <NUM> the current alignment and correct to match the stored coordinates.

In some embodiments, the gun-sight zeroing system may be inserted into the barrel using a rod. In some embodiments, the zeroing target may use IR radiation and/or visible light, etc. In some embodiments, the focal length of the lens in the focusing assembly may be adjusted, for example by moving the lens closer and/or further from the target.

<FIG> is a block diagram of a dry gun-sight zeroing system in accordance with an embodiment of the current invention. For example, in system <NUM>, the focusing assembly <NUM> may include one or more multiband lenses (not shown) and a switching mechanism <NUM>. Optionally, the switching mechanism <NUM> may be configured to facilitate reversibly switching between two or more configurations, e.g., an optical sighting configuration and a thermal sighting configuration. The focusing assembly <NUM> may be associated with a zeroing target <NUM>. Optionally, the zeroing target <NUM> may be connected to one or more thermistors <NUM>, <NUM> and a cooling/heating system <NUM>. Optionally, the cooling/heating system <NUM> may be any system which may increase the visibility of a target when using a thermal sighting configuration, e.g., heat source or heat sink, etc. The one or more thermistors <NUM>, <NUM> and the cooling/heating system <NUM> may be connected to a controller <NUM>. The controller <NUM> may activate and/or deactivate the cooling/heating system <NUM> based on one or more signals from one or more thermistors <NUM>, <NUM>. Optionally, the controller <NUM> may be connected to an illumination source <NUM>, e.g., visible light source. Optionally, the illumination source <NUM> may illuminate the zeroing target <NUM> and/or one or more elements of the focusing assembly <NUM> and/or an area therebetween e.g., to act as a light chamber. The controller <NUM> may activate and/or deactivate the illumination source <NUM>, e.g., when moving from one configuration to another configuration. The controller <NUM> may be connected to a power source <NUM>.

Claim 1:
A zeroing assembly for a gun-sight comprising:
a zeroing target (<NUM>);
characterized by:
a dual band lens (<NUM>); and
a switching mechanism (<NUM>) configured to reversibly move the dual band lens (<NUM>) from a first position (302a) to a second position (302b) along its optical axis (<NUM>), thereby switching the zeroing assembly from a first sighting configuration wherein light in a first band from said zeroing target (<NUM>) is focused on a gun sight to a second sighting configuration wherein light in a second band from said zeroing target (<NUM>) is focused on said gun sight.