The invention relates to a portable observation device having an observation path for optical targeting of a target object, and comprising an optoelectronic rangefinder for measuring the distance in the direction of the targeting. The rangefinder includes a transmission unit for emitting a temporal sequence of pulses of optical radiation, a reception unit for receiving a portion of the optical radiation cast back by the target object and for determining signal information and an electronic evaluation unit, which a distance to the target object can be determined on the basis of a signal travel time between emission and reception of the optical radiation. When a trigger is actuated manually, the distance is determined including the signal information from a specified minimum number of pulses, which define a minimum length of a time window of the distance measurement.