Well as we all know it is very critical calculating all the conditions needed to achieve the 1000+ hits so I figured I would post detailed instructions on slant range determination.
Math Wizard Method
1. Vertical Distance (atan) (cos) x range to target = slant range to target
2. Determine your range to target (Mil, Laser, GPS, etc)
3. Determine your vertical distance above or below your target
4. Divide the vertical distance by range to target
5. Press "ATAN" of "Tan-1" key on your calculator
6. Press "COS" key on your calculator
7. Multiply the result of above process against range to target
8. Result is slant range
Simple Method
1. Use a protractor or other method to get a direct reading in degrees, then use the COSINE function to convert that angle to a correction factor (I have listed the correction factors in 5deg increments below)
2. Multiply this correction factor against true range
3. True range x COS of angle to target = slant range
4. Example 1600(true range) x 25deg(.90631 correction factor) = 1450.09 meters slant range BUT be sure to calculate meteorological calculations from true range. The slant range is what is indexed on sight system.
Slope Angle Degree/Correction Factor
5 / .99619
10 / .98481
15 / .96593
20 / .93969
25 / .90631
30 / .86603
35 / .81915
40 / .76604
45 / .70711
50 / .64279
55 / .57358
60 / .50000
65 / .42262
70 / .34202
75 / .25882
80 / .17365
85 / .08716
Math Wizard Method
1. Vertical Distance (atan) (cos) x range to target = slant range to target
2. Determine your range to target (Mil, Laser, GPS, etc)
3. Determine your vertical distance above or below your target
4. Divide the vertical distance by range to target
5. Press "ATAN" of "Tan-1" key on your calculator
6. Press "COS" key on your calculator
7. Multiply the result of above process against range to target
8. Result is slant range
Simple Method
1. Use a protractor or other method to get a direct reading in degrees, then use the COSINE function to convert that angle to a correction factor (I have listed the correction factors in 5deg increments below)
2. Multiply this correction factor against true range
3. True range x COS of angle to target = slant range
4. Example 1600(true range) x 25deg(.90631 correction factor) = 1450.09 meters slant range BUT be sure to calculate meteorological calculations from true range. The slant range is what is indexed on sight system.
Slope Angle Degree/Correction Factor
5 / .99619
10 / .98481
15 / .96593
20 / .93969
25 / .90631
30 / .86603
35 / .81915
40 / .76604
45 / .70711
50 / .64279
55 / .57358
60 / .50000
65 / .42262
70 / .34202
75 / .25882
80 / .17365
85 / .08716
