Here is a chart my dad and I made for several hours to get a decent calculation on speed. Remember, the farther you are from the target, the harder it will be to get an accurate speed. Hope you enjoy it
! Please post a reply on how it worked for you or any questions! The end result is speed in knots. Please note that this chart is most accurate when observing from an AOB of 90 degrees. When calculating you may have to estimate to the half-degree, this is just a solid reference.
To use:
1) Find range of target
2) Start clock and measure change in degrees in 10 seconds
3) Use the chart to find target speed
Happy Hunting!
