A telescoping boom, comprising: a base section having a base end and a telescoping end; a first telescoping section disposed within the base section, the first telescoping section having a first pin receiver configured to receive a pin, and including a bottom having a first angular orientation; a second telescoping section disposed within the first telescoping section, the second telescoping section having a second pin receiver configured to receive the pin and including a bottom having a second angular orientation different to the first angular orientation; a linear actuator disposed within the base section, the linear actuator having a stationary portion and an actuated portion configured to extend and retract longitudinally relative to the base section; a rotary element coupled to the actuated portion, the rotary element having an axis of rotation parallel to a longitudinal axis of the base section and a pin perpendicular to the axis of rotation, the rotary element having a first configuration in which the pin engages the first telescoping section and a second configuration angularly offset from the first configuration in which the pin does not engage the first telescoping section; and a rotary actuator coupled to the base section and the rotary element, the rotary actuator configured to rotate the rotary element and the pin relative to the base section, the rotary actuator having a rotational encoder adapted to indicate which of the first and the second telescoping section (18, 20) the pin is engaged with by measuring the angular orientation at which the pin encounters the bottom of the first or the second pin receiver. a base section having a base end and a telescoping end; a first telescoping section disposed within the base section, the first telescoping section having a first pin receiver configured to receive a pin, and including a bottom having a first angular orientation; a second telescoping section disposed within the first telescoping section, the second telescoping section having a second pin receiver configured to receive the pin and including a bottom having a second angular orientation different to the first angular orientation; a linear actuator disposed within the base section, the linear actuator having a stationary portion and an actuated portion configured to extend and retract longitudinally relative to the base section; a rotary element coupled to the actuated portion, the rotary element having an axis of rotation parallel to a longitudinal axis of the base section and a pin perpendicular to the axis of rotation, the rotary element having a first configuration in which the pin engages the first telescoping section and a second configuration angularly offset from the first configuration in which the pin does not engage the first telescoping section; and a rotary actuator coupled to the base section and the rotary element, the rotary actuator configured to rotate the rotary element and the pin relative to the base section, the rotary actuator having a rotational encoder adapted to indicate which of the first and the second telescoping section (18, 20) the pin is engaged with by measuring the angular orientation at which the pin encounters the bottom of the first or the second pin receiver.