US 20020129535 A1
A scope for use on a long-range firearm comprises a pulse train of light that moves across the field of view of the scope. A shooter may synchronize the pulse train of light to the speed with which a mirage image moves across the field of view to estimate a wind speed at a target location.
1. A passive wind reading scope, comprising:
a scope comprising a field of view in which to view a target;
indicia translating across said field of view; and
a display associated with said scope providing information derived in part from a time taken by said indicia to translate across said field of view, said information for use by shooter to compensate for wind crossing said field of view.
2. The passive wind reading scope of
3. The passive wind reading scope of
4. The passive wind reading scope of
5. The passive wind reading scope of
6. The passive wind reading scope of
7. A passive wind reading scope comprising:
a scope comprising a field of view, said field of view displaying indicia that translates thereacross and controlled by said controller;
a display communicatively connected to said controller and providing information related to a wind speed between the scope and a target; and
a user input device communicatively connected to said controller, said user input device instructing said controller to control translation of said indicia;
wherein a mirage may be viewed through said scope and a shooter may use said user input device to match a speed with which said indicia moves across said field of view with a speed with which said mirage moves across said field of view, thereby generating with the controller an estimate of wind speed that said controller uses when generating said information.
8. The passive wind reading scope of
9. The passive wind reading scope of
10. The passive wind reading scope of
11. A rifle comprising:
a pinion assembly; and
a passive wind reading scope comprising:
a scope mounted on said pinion assembly, said scope comprising a field of view with a plurality of LEDs positioned within said field of view, said LEDs sequentially emitting light to form a pulse train of light that translates across said field of view, said scope comprising an output display within said field of view for outputting information related to a wind speed and wind direction;
a controller positioned in said scope and communicatively connected to said plurality of LEDs and said output display;
a user input device communicatively connected to said controller for controlling a speed with which said pulse train translates across said field of view through said controller;
wherein a mirage may be viewed through said scope and a shooter may use said user input device to match the speed with which said pulse train moves across said field of view with a speed with which said mirage moves across said field of view, thereby generating an estimate of wind speed for use by said controller in generating said information.
12. The rifle of
13. The rifle of
14. The rifle of
15. The rifle of
16. A method of using a firearm, comprising:
associating a passive wind reading scope with a firearm;
viewing a target in a field of view in the scope;
matching a speed with which indicia crosses the field of view to a speed with which a heat induced mirage crosses the field of view; and
displaying information related to a wind speed based on time elapsed for said indicia to cross the field of view.
17. The method of
18. The method of
19. The method of
20. The method of
21. A passive wind reading scope, comprising:
a scope adapted for attachment to a rifle, said scope comprising a field of view in which to view a target;
indicia translating across said field of view; and
a display associated with said scope providing information derived in part from a time taken by said indicia to translate across said field of view, said information for use by shooter to compensate for wind crossing said field of view.
22. The passive wind reading scope of
23. The passive wind reading scope of
24. The passive wind reading scope of
25. The passive wind reading scope of
26. The passive wind reading scope of
27. The passive wind reading scope of
28. The passive wind reading scope of
29. The passive wind reading scope of
30. The passive wind reading scope of
31. A passive wind reading scope, comprising:
a scope adapted for attachment to a rifle, said scope comprising a field of view in which to view a target; and
a clinometer integrated into said scope for determining a slope of a rifle on which the scope may be positioned.
 1. Field of the Invention
 The present invention relates to aiming scopes for use on firearms, and particularly rifles.
 2. Description of the Related Art
 Firearms have evolved substantially since the first harquebus into precision rifled machines capable of shooting a projectile distances well in excess of a thousand yards. Uses for such firearms are myriad. In times of war, snipers may use such weapons to eliminate key figures in the enemy's ranks. Police, hostage rescue teams, and anti-terrorism forces may also use such weapons to eliminate key enemies without risking their personnel or hostages. Sportsmen and hunters may shoot these weapons as an alternative to other shooting forms. Common amongst all of these types of long range shooting is the use of a scope through which the shooter may view the target.
 The simplest scopes are fixed power scopes. Such scopes provide a fixed magnification (e.g., 3×, 10×, 20×) with which the shooter may be able to see a target at a distance. The military has used range compensating sniper scopes that incorporate Horizontal and Vertical stadia lines on a reticle that assist aiming because they represent fixed vertical and horizontal distances between the stadia lines at all aiming ranges. These features allow snipers to aim simply by rotating one or more cams (integral with the rear barrel of the scope) until the horizontal stadia lines bracket the now in focus target from belt-buckle to head.
 One problem associated with such long distance shooting is compensating for environmental factors and the ballistic coefficient of the projectile that otherwise may alter the trajectory of the projectile away from the intended target. A shooter taking a typical long-range shot initially determines the straight-line distance to the target. This distance is converted for the slope between the shooter and the target. Then the shooter compensates for temperature, relative humidity, and barometric pressure. Finally, the shooter adjusts for a crosswind that may be present at the target area.
 There are also at least two common aiming aids frequently incorporated into the scopes through which the shooter is assisted in compensating for the environmental conditions. The first is a permutation on the aforementioned stadia lines known as “mil dots.” A compensation or “hold off” is calculated, and the shooter positions the target within the field of view of the scope at the appropriate mil dot, as determined by the hold off. The second aiming aid comprises a set of cams integrated into the scope that change the position of a cross hair within the reticle. These cams frequently are expressed in terms of minute of angle (MOA). A hold off is still calculated, but this time the result is returned in MOA. The shooter turns the appropriate cams by the indicated hold off, and the cross hair of the reticle is now no longer on the target. Recentering the cross hair on the target effectively aims the gun at the desired hold off and the shot may be taken.
 Temperature, relative humidity, and barometric pressure may be sensed at the shooter's location. Such passive detection helps eliminate the risk that the target will sense the presence of the shooter. For example, many tanks these days have IR detectors on them to determine if they are being ranged. Upon receipt of an alert, the tank may take the appropriate defensive actions. While most targets are not as sophisticated as such tanks, the risk may still exist that active sensing may alert the target. Experienced shooters relatively easily estimate the distance and slope to the target. Alternatively, predetermined intelligence in the form of maps, satellite imagery, aircraft photography and the like may be used to calculate a range to target. Where active sensing is not an undesirable feature, laser range finders, such as those sold by Schwartz Electro-optics of 3440 Orange Blossom Trail, Orlando, Fla. 32804 may be used.
 At times, shooters may use “spotters” to help call a shot. The spotter may be positioned proximate to, or remote from, the shooter and provide valuable information to the shooter about wind speed, atmospheric conditions, and the like. The spotter communicates these conditions to the shooter and may make aiming recommendations.
 The problem lies in estimating the wind. In this case, heretofore, the shooter is forced to make a guess or use an active sensor. The first technique may not be particularly reliable, and the second may alert the target. While spotters may alleviate some of these problems, spotters are not always available, nor do they always have all the information needed to help the shooter properly.
 The present invention relates to a scope that may be coupled to a firearm. The scope is designed to aid the shooter in determining crosswind speed at the target so that the shooter may compensate for this crosswind prior to pulling the trigger.
 The scope of the present invention does this by allowing the shooter to look through the scope at the target and match the speed with which a pulse train of lights crosses the field of view to the speed with which the mirage crosses the field of view. The pulse train of lights may be formed by light emitting diodes or the like. Alternatively, other equivalent indicia may translate across the field of view. When the speed of the pulse train of lights matches the speed with which the mirage moves, a controller outputs on a display a wind speed that the shooter may use in his calculations of the shot. As another alternative, the controller may output a recommended shot adjustment for the shooter to make prior to pulling the trigger.
 A calibration routine is also provided. The scope maybe positioned at a fixed location on a calibration range. The calibration range is equipped with several moving targets at predetermined distances from the scope. The scope is sighted on a given target at a given distance. Thus, left to right distance visible within the field of view may be determined based on known distance markers viewable near the target. The target moves across the field of view at a predetermined speed. The calibration matches the speed of the pulse train of lights to the speed of the target and determines how long it takes for the pulse train to cross the field of view. This time is stored along with the predetermined speed of the target as well as the distance to the target. This process is repeated for numerous speeds and ranges and the values stored in a look up table or the like for future use.
 Thus, after calibration, when a shooter matches the pulse train to the speed with which the mirage moves, the shooter is able to obtain an accurate estimation of the crosswind speed at the target—without using an active sensor—by the controller matching the time it takes the mirage to cross the field of view at a particular range to a time and range in the look up table.
FIG. 1 illustrates a perspective view of a firearm with one embodiment of a scope according to the present invention mounted thereon;
FIG. 2 illustrates a schematic drawing of the components of the scope of one embodiment of the present invention;
FIG. 3 illustrates an alternate embodiment of certain components removed from the firearm;
FIG. 4 illustrates a cross-sectional view of one embodiment of a scope adapted for use with the present invention;
FIG. 5 illustrates an exemplary view when looking through the scope of the present invention;
FIG. 6 illustrates a flow chart exemplifying use of the scope of the present invention;
FIG. 7 illustrates a flow chart exemplifying calibration of the scope of the present invention; and
 FIGS. 8-13 illustrate alternate embodiments of the mechanism by which indicia may travel across the field of view
 A sniper rifle such as the M21, M25, Barrett M-82A1, Barrett Model 98, or other equivalent models may be used with the scope of the present invention. Some of these may need to be modified in certain embodiments. A rifle, denoted in FIG. 1, generally by the numeral 10, may include a stock 12, a barrel 14, a magazine or clip 16 containing ammunition (not shown), a pinion assembly 18 and a scope 20 mounted on the pinion assembly 18.
 Scope 20 may be a range adjusting sniper scope or a fixed power scope with auxiliary components. Collectively, the scope 20 and these auxiliary components are herein referred to as “passive wind reading scope 50.” Passive wind reading scope 50 is designed to assist the shooter using the rifle 10 by providing information about the environmental conditions. These conditions may be factored into the positioning and aiming of the rifle 10 so that a shot will hit the intended target.
 One embodiment of the passive wind reading scope 50 is illustrated schematically in FIG. 2. Passive wind reading scope 50 may comprise a controller 52, a thermometer 54, a barometric pressure sensor 56, a relative humidity sensor 58, a user input device 60, and a clinometer 62. Thermometer 54, barometric pressure sensor 56, and relative humidity sensor 58 all sample the environment and report the respective sensed conditions to the controller 52. Clinometer 62 may sense the level of the rifle 10 to determine the slope to the target. Controller 52 may be a microprocessor such as an INTEL PENTIUM, HITACHI SH1, MOTOROLA 68000, INTEL MCS296 device or the like. Controller 52 also controls display 22 within scope 20 as will be explained in greater detail below.
 In one embodiment, the controller 52, thermometer 54, barometric pressure sensor 56, and relative humidity sensor 58 may be positioned in the stock 12 of the rifle 10. This positioning may require the stock 12 to be modified. However, changing stocks and other components of rifle 10 is well understood. User input device 60 may be a rocker switch or a plurality of buttons as needed or desired and can be positioned proximate the trigger guard of the rifle 10 or at other places on the rifle 10 such as the stock 12 or the like as needed or desired.
 In an alternate embodiment, illustrated in FIG. 3, a box 70 may be provided that communicates with the scope 20 through a wire 84, an RF link, or other type of communication link. In particular, box 70 may comprise a display 72, a rocker switch 74, a power button 76, a plurality of sensor apertures 78, 80, 82, a keypad 90 and scroll buttons 92.
 Display 72 may output a direction character 86 and speed 88 such as left thirteen (illustrated) or right five. This is indicative of the calculated speed of the wind and the direction it is blowing relative to the aiming path of the rifle 10.
 Rocker switch 74, through controller 52, may speed up or slow down the speed with which a pulse train of lights crosses the field of view of scope 20 as is explained in greater detail below. Rocker switch 74, in this embodiment, is user input device 60.
 Power button 76 may be a conventional push button and actuates power in the box 70 and may trigger a battery (not shown) or the like as needed or desired.
 Sensor apertures 78, 80, 82 may allow thermometer 54, barometric pressure sensor 56, and relative humidity sensor 58 (all positioned within box 70) to sense atmospheric conditions for reporting to the controller 52 (not shown, but positioned within box 70). Alternatively, these sensors 54, 56, 58 may share a single aperture or may even be a combined sensor as needed or desired. As yet another alternative, these sensors 54, 56, 58 may be positioned on the exterior of box 70. Information derived from the sensors 54, 56, 58, and clinometer 62 may be displayed on display 72 as needed or desired. For example, display 72 could cycle through the output in a predetermined fashion. It is also contemplated that instead of rocker switch 74, user input device 60 could be a pair of buttons (not shown) that act in much the same manner as a rocker switch, with each button acting to change the speed of the pulse train in a desired direction.
 Keypad 90 and scroll buttons 92 may be used by the shooter to input information to the controller 52 that is otherwise unavailable to the controller 52. For example, the shooter may input the range to target via keypad 90. Scroll buttons 92 may be used to cycle through a menu of information that the shooter may desire to enter. Exemplary items of information aside from range include ballistic coefficient; environmental conditions if sensors 54, 56, 58 are not present; slope to target if clinometer 62 is not present; and the like. Other options to enter this information are also possible. For example, the shooter may turn a dial (not illustrated) positioned on the side of scope 20 to the desired range and controller 52 may sense the position of this dial to detect the range.
 In still another embodiment (not illustrated), the controller 52 and sensors 54, 56, 58 may be integrated into the scope 20 or positioned on the scope housing 28 (FIG. 4). This may enable better packaging and selling opportunities, as well as eliminate wires passing from the controller 52 to the scope 20.
 Turning now to scope 20 proper, a cross-sectional view is illustrated in FIG. 4. Scope 20 may comprise a housing 28, a plurality of lenses 30, the display 22 having LEDs 34 disposed thereon, and a connector 36. Housing 28 may be a housing such as that sold by BUSHMASTER under the tradename SPACEMASTER EYEPIECE 20X. Scope 20 may be a range adjusting scope or a fixed power scope as needed or desired.
 Lenses 30 are conventional lenses such as are commonly used in scopes. Display 22 may be a pane of glass, polymeric material, or other transparent material that does not materially affect the optical effects of the lenses 30. Alternatively, if the display 22 does affect the optical effects of the lenses 30, this impact should be well documented so that lenses 30 may compensate for this impact. LEDs 34 may equivalently be other light emitting structures, liquid crystal structures, or the like as needed or desired. In one embodiment there are between 12-16 LEDs 34, although both lower and higher numbers of LEDs 34 are contemplated. Practically, at least four LEDs 34 are needed and as many as twenty or more may conceivably be positioned on or in display 22. Connector 36 may be a fifteen position male D-dub connector and connect to wire 84 as needed or desired for communication with the controller 52.
 Scope 20 may include a set of cross hairs viewable when peering through the scope 20. These cross hairs may be bracketed by stadia lines (shown), mil dots, or be repositionable by a set of cams positioned on the scope. Such features are well understood. It is further possible that the scope 20 may include a range dial that communicates with the controller 52. The shooter selects the range to the target on the dial, and the controller 52 uses this information where appropriate.
 The shooter using the scope 20 may see something comparable to what is illustrated in FIG. 5 wherein the field of view 40 of the scope 20 is illustrated. Note that for clarity only the stadia lines and not the crosshairs, mil dots, and other such indicia are illustrated, but it is to be understood that such may be present. In the embodiment illustrated, display 22 includes wind direction indicators 24, an output display 26, and a clinometer display 62′. Additionally, there may be unit of measure indicators 42, 44 that indicate which unit of measure the shooter is using (mils 42 or minute of angle (MOA) 44). The LEDs 34 will sequentially light up, forming a pulse train that moves across the field of view, and repeating when the pulse reaches the last LED 34 on either side of the field of view 40. This pulse train may be slowed, sped up, or reversed by the controller 52 based on input from the user input device 60.
 A mirage 45 may be visible through the scope 20. “Mirage” refers to the phenomenon where heat waves in the air are visible. If there is wind, the mirage 45 will drift with the wind, generally at the speed of the wind. Through the use of the user input device 60 (such as rocker switch 74), the shooter may match the speed of the pulse train to the speed with which the mirage 45 moves. Thus, for example, if the pulse train is initially moving from left to right, taking four seconds to cross the display 22, holding the rocker switch 74 down on one side may speed up the pulse train so that it crosses the field of view in two seconds, reflecting a faster moving mirage 45. Alternatively, for example, if the wind is actually blowing right to left, holding down the other side of rocker switch 74 will slow the pulse train down and eventually reverse the direction of the pulse train gradually picking up speed until it matches the speed and direction with which the mirage 45 moves. Wind direction indicators 24 will indicate which direction the pulse train is moving at that moment, reflecting the direction that the shooter is “telling” the passive wind reading scope 50 the wind is blowing.
 Output display 26 may be a multipurpose display. In one embodiment, the output display 26 will display the wind speed based on the speed of the pulse train (in effect acting like display 72). For example, once the user input device 60 has not been manipulated for a predetermined period of time (e.g., two seconds), the controller 52 would reference the range setting (as determined by input through the keypad 90 or other means), and establish a left to right dimension associated with the field of view at the target. For example, at a range of 200 meters, the left to right field of view is eight meters. This dimension, divided by the time it takes the pulse train to cross the field of view 40 equals a crosswind speed. This may be done mathematically every time, or may be referenced in a look up table or the like. The more LEDs 34 (or equivalents) that are present, the more resolution the shooter has to match the speed of the pulse train to the speed of the mirage 45. Thus, four LEDs 34 would give a very rough estimate of the wind speed, but twelve to twenty would provide a much more accurate estimate.
 Output display 26 may also serve to output information relating to environmental conditions as reported by sensors 54, 56, 58. Additionally, the output display 26 may tell the shooter exactly what adjustment to make to the shot to compensate for all the factors. In this embodiment, the controller 52 takes into consideration the range to target, the slope, the ballistic coefficient of the projectile, the environmental conditions (temperature, relative humidity, barometric pressure), and the crosswind speed, compares these factors to a look up table or performs the math and tells the shooter to hold off a particular amount in a particular direction. E.g. three mils left or six MOA right. The shooter may then take this into account as he makes the shot. It is also possible that instead of using the output display 26, the appropriate LED 34 may illuminate indicating the hold off for the shooter, although this is not necessarily preferred.
 Wind direction indicators 24, the output display 26, clinometer display 62′, and unit of measure indicators 42, 44 may be positioned against a dark background 46 so as to provide greater contrast if needed or desired.
 Several alternate embodiments of the indicia translating across the display 22 are provided below with reference to FIGS. 8-13.
 An exemplary method of using the passive wind reading scope 50 of the present invention is illustrated in FIG. 6. The shooter takes a position with a calibrated passive wind reading scope 50 and rifle 10. Rifle 10 is then set up conventionally and aimed in the general direction of the target. The shooter then finds the target through the scope 20, and particularly in the scope 20's field of view 40 (block 100). The shooter focuses on the target (block 102). The shooter may enter the range to target information through the keypad 90, by turning a dial on the scope, or other appropriate means. From this input, controller 52 may sense the range to the target (block 104). Controller 52 may sense through input from the clinometer 62, through entry via keypad 90, or other means, the slope to the target (block 106). Concurrently with these steps, before, or after (as needed or desired) sensors 54, 56, 58 may sense atmospheric conditions (block 108) and report them to the controller 52. Alternatively, the shooter may enter this data through the keypad 90. The shooter then turns his attention to the mirage 45 viewable through the scope 20 (block 110). The shooter then compares the movement of the mirage 45 to the pulse train of lights created by the LEDs 34 (block 112). The shooter uses the user input device 60 (such as rocker switch 74) to match the direction of the pulse train to the perceived movement of the mirage 45 (block 114). The shooter matches the speed with which the pulse train crosses the field of view 40 to the speed with which the mirage 45 crosses the field of view 45 (block 116). This speed matching is accomplished through manipulation of the user input device 60 as previously noted. Controller 52 evaluates the speed of the pulse train across the field and view and particularly the time elapsed for the pulse train to cross the field of view (block 118). This may be done a number of ways such as timing the time elapsed between the firing of the first and last LEDs 34, the time elapsed between successive firings of the first LED 34, or other equivalent means. Controller 52 references the time elapsed against the range (block 120) and particularly the dimension associated with the field of view 40 at that range. From these two values, the controller 52 may determine the speed of the wind at the target (block 122). This may be done by performing the math or through a look up table as previously noted. Controller 52 then displays a wind speed and direction on the output display 26 or 72 (block 124). In one embodiment, the controller 52 then outputs a recommended vertical and horizontal offset. If this output is in mils, the shooter positions the appropriate mil dot on the target and makes the shot. If the output is in MOA, the shooter makes the appropriate cam adjustments to the scope to reposition the crosshairs within the reticle and recenters the crosshairs on the target and makes the shot. In another embodiment, the output display 26 or 76 may be modified to display all the various environmental factors and the shooter may do the math himself to determine the appropriate adjustments prior to making the shot. Numerous tables exist, such as those produced by Tioga Engineering Company, Inc., (PO Box 913, Wellsboro, Pa. 16901) that the shooter may reference to determine the appropriate adjustments.
 Reliance on the passive wind reading scope 50 to perform accurately requires calibration of the passive wind reading scope 50. An exemplary calibration methodology is illustrated in FIG. 7. Initially, the calibration range is established (block 200). This comprises establishing a scope position area and a plurality of targets at known range increments. These targets may be movable across a known distance at a number of known speeds. The calibrator selects a first target at a first range (block 202) and enters an appropriate range setting. The shooter may initially position the target on the left hand side of the field of view 40 in the scope (block 204). The target is released and moves at a first predetermined speed across the field of view (block 206). The shooter matches the speed and direction of the pulse train to the speed and direction of the target (block 208). The target may have to repeat the process several times until the matching is accomplished. In one embodiment, the target is not a moving target, but rather a series of light emitting (or equivalent) sources that sequentially emit light, simulating a moving light, very similar to the LEDs 34 used in the scope 20. Regardless of the nature of the target, when the pulse train in the scope 20 and the target are synchronized, the controller 52 calculates the time elapsed for the pulse train to cross the field of view 40 (block 210). This time is stored in a look up table along with the known speed of the target at the predetermined range (block 212). This process is repeated for different speeds at the first range (block 214). Again, this process is repeated for different ranges (block 216). Not every range and speed need be calibrated, but a sufficient number should be done so that intermediate results may be interpolated from the values that are calibrated.
 Once a full set of data points have been recorded in memory (not shown explicitly) by controller 52, the passive wind reading scope 50 is considered calibrated and the process ends (block 218). Passive wind reading scope 50 is now ready for use by the shooter. Note that other calibration techniques may also be possible.
 While the present invention has been described as a pulse train of lights created by a series of sequentially firing LEDs 34, other translating indicia are also contemplated. FIGS. 8-13 detail several of these alternate embodiments. In FIG. 8, the indicia 300 may be formed by a mechanical rotating assembly 302 with one or more light or laser emitters 304 mounted on a spindle 306 driven by gears 308, 310. The rotational speed of the emitter 304, as adjusted by the shooter would indicate the wind speed. Again, the controller 52 would take this value and calculate a desired hold off for the shooter. Drive shaft 312 may include a hollow shaft 314 for wires to pass through to power the emitters 304. A rear plate 316 may optionally be included to prevent light from being emitted through the scope 20 towards the target.
 Another alternate arrangement is the use of a light emitting structure mounted in a slot or groove and continuously rotating in a manner similar to a chain driven bicycle. This is illustrated in FIGS. 9-11. A drive gear 350 maybe positioned in the scope 20 with two pulleys 352, 354 helping position a “chain” 356 therearound. This drive mechanism may be tilted with a shield 358 positioned therebehind. The tilt effectively casts light against shield 358. Chain 356 maybe one of a number of embodiments, two of which are presented in FIGS. 10 and 11. In the embodiment of FIG. 10, a rubber belt 360 may have a plurality of emitters 362 mounted thereon. In the embodiment of FIG. 11, chain 356 may comprise a plurality of links 370, each with an emitter 372 positioned thereon. Each chain 356 may have positive and negative conductive strips on the underside to provide power to the emitters 362, 372. Power could be provided through the pulleys 352, 354 as needed or desired. Pulleys 352, 354 may be three piece components with a conductive positive side, a ceramic disc center, and a conductive negative side sandwiching the ceramic disc. Again, the shooter matches the speed with which the light emitting structure crosses the field of view to the speed of the mirage and the controller 52 calculates a desired hold off.
 Another alternate arrangement is the use of an animated object of any sort moving across a miniaturized viewing screen 400 as illustrated in FIG. 12. This screen 400 may be positioned, for example, in the lower third of the field of view 40. The speed with which the animation moves across the screen may be controlled by the shooter. From this speed, the controller 52 may calculate a wind speed and a desired hold off.
 Another alternate embodiment is the use of a liquid crystal display with a continuous series of “waves” or other desired representation moving across a gray screen. This screen may occupy, for example, the lower portion of the field of view 40. The speed with which the waves cross the field of view 40 may be adjusted by the shooter and from the speed, the controller 52 may determine a wind speed and desired hold off. In appearance, this would be substantially similar to the viewing screen 400 of FIG. 12.
 Another alternate embodiment is the use of small beads 402 or objects pressed to or fixed to a wire 404 or line that is passed around two rollers 406, 408, as illustrated in FIG. 13. First roller 406 may be driven in a fashion similar to the spindle 306 of FIG. 8. The object moves across a neutral colored field of view 40. Again, the shooter matches the speed with which the object crosses the field of view to the speed of the mirage, and controller 52 calculates the wind speed and desired hold off based on the rotational speed of roller 406.
 Still another alternate embodiment is the user of small rods of metal, or other objects laying flat in two rows, one row hinged on the left end and the other row hinged on the right end. These rows may be raised and lowered by a rotating assembly comparable to the bicycle chain described above. The rotating assembly “bumps” the rods from underneath like a camshaft and pushrod assembly, causing the rods to point up in a sequential manner to simulate a wave action across the field of view 40. One row could be used for left to right wind and the other row used for right to left wind. The movement of the rotating assembly may be tracked, and from that tracking, the controller 52 may calculate a wind speed and desired hold off.
 The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.