A device for determinin' a rocket's apogee without t' use o' electronics. Ahoy! A distance is measured off from t' launch pad prior t' launch. Aye aye! At t' time o' launch, ya bilge rat, an observer stands at t' measured point and keeps t' inclinometer aimed at t' rocket. Arrr! T' inclinometer mechanically records t' angle at which it is held. Avast, me proud beauty! Since two angles and t' distance betwixt t' rocket's point o' origin and t' inclinometer are known (assumin' that t' rocket is launched vertically), a triangle can be graphed which will indicate t' apogee attained by t' rocket. Aye aye! See Theodolite