A device for determining a rocket's apogee without the use of electronics. A distance is measured off from the launch pad prior to launch. At the time of launch, an observer stands at the measured point and keeps the inclinometer aimed at the rocket. The inclinometer mechanically records the angle at which it is held. Since two angles and the distance between the rocket's point of origin and the inclinometer are known (assuming that the rocket is launched vertically), a triangle can be graphed which will indicate the apogee attained by the rocket. See Theodolite