Ballistic Coefficient (Time) Terms
- Used in estimating the atmospheric conditions. This value is not
used unless the "Standard Conditions at Altitude" checkbox or the "Pressure is Corrected"
checkbox is checked.
- Timer Separation
- The distance over which the time is measured. For a setup of
a chronograph and timer, the distance is measured from the center of the chronograph
(start of time) to the second timer detector which turns off the timer.
- Drag Function
- A drag function (or G function) provides the forces on a standard
bullet for which the drag function was derived. A bullet's ballistic
coefficient then relates the drag on any bullet to that of the standard
- Near Velocity
- The velocity of the bullet at the beginning of the measured distance.
- The barometric pressure. It may be corrected or uncorrected
depending on the state of the "Pressure is Corrected" checkbox.
- Pressure is Corrected
- Check this box if the pressure entered is a corrected station
pressure. If it is an absolute pressure, leave this unchecked.
- Relative Humidity
- Relative humidity (percent)
- Standard Conditions at Altitude
- When checked, the temperature, pressure and humidity for standard
atmospheric conditions at the entered altitude (always 0% at standard
conditions) are entered in the calculation. The standard used is the ICAO
- The measured or estimated air temperature.
- The measured time of flight of the bullet over the entered distance. This
value needs to be entered to an accuracy of a microsecond.
- Ballistic Coefficient
- The calculated ballistic coefficient for the selected drag function.
- Atmospheric Density
- The calculated density of the air.
- Far Velocity
- The calculated velocity at the end of the measured distance.
- Speed of Sound
- The calculated speed of sound.
Note: If a ballistic coefficient cannot be found with the input values, the text "***" will
be displayed for the ballistic coefficient and far velocity.