Reticle for stadiametric rangefinding
View Patent ↗A reticle for stadiametric rangefinding has a horizontal crosshair and a vertical crosshair that are attached to an optical element. The optical element defines an optical axis and a field of view. The crosshairs intersect perpendicularly at a location that is offset from the optical axis. There may be a plurality of rangefinding indicia shaped to indicate the size of an object at a specific range. The rangefinding indicia may be arranged in a position other than vertical.
1. A rangefinding reticle for an optical device having optical element that defines an optical axis and a field of view, the reticle comprising:
a horizontal crosshair attached to the optical element;
a vertical crosshair attached to the optical element;
the crosshairs intersect perpendicularly at a location; and
the location being offset from the optical axis.
2. The reticle of claim 1 wherein each of the crosshairs is offset from the optical axis by a distance equal to at least 5% of the field of view's diameter.
3. The reticle of claim 1 wherein a portion of the field of view that contains the optical axis and is bounded by the crosshairs has a surface area equal to at least one-third of the field of view's surface area.
4. The reticle of claim 1 further comprising a plurality of rangefinding indicia shaped to indicate the size of an object at a specific range, the rangefinding indicia being arranged in a position other than vertical.
5. The reticle of claim 4 wherein the rangefinding indicia are positioned side-by-side in a horizontal arrangement.
6. The reticle of claim 5 wherein the rangefinding indicia have bottoms that are vertically aligned parallel to the horizontal crosshair.
7. The reticle of claim 4 wherein the rangefinding indicia are separated from the optical axis by the horizontal crosshair.
8. The reticle of claim 1 wherein the crosshairs each comprise a thinner line portion and a thicker bar portion, the bar portions being separated from the line portions by a gap.
9. The reticle of claim 8 wherein the line portions of the crosshairs each comprise major stadia marks, a distance between adjacent major stadia marks defining a unit of angular measurement.
10. The reticle of claim 9 wherein the gaps separate the bar portions from their corresponding line portions by a distance corresponding to one unit of angular measurement.
11. The reticle of claim 1 wherein the location is offset from center of a circular field of view.
12. A rangefinding reticle for an optical device having an optical element that defines an optical axis and a field of view, the reticle comprising:
a primary measuring reference point attached to the optical element; and
the reference point being offset from the optical axis.
13. The reticle of claim 12 wherein the reference point is defined by a location where a horizontal crosshair attached to the optical element and a vertical crosshair attached to the optical element intersect perpendicularly.
14. The reticle of claim 13 wherein the crosshairs each comprise major stadia marks, a distance between adjacent media stadia marks defining a unit of angular measurement.
15. The reticle of claim 12 wherein the reference point is offset from center of a circular field of view.
16. The reticle of claim 14 wherein each of the crosshairs is offset from the optical axis by a distance equal to at least 5% of the field of view's diameter.
17. The reticle of claim 14 , wherein each of the crosshairs is offset from the optical axis by a distance equal to no more than 10% of the field of view's diameter.