1. A handheld observation device comprising a digital magnetic compass for measuring a magnetic field direction of a magnetic field present, a gravitation sensor for measuring a gravitational field direction of the gravitational field present, and a control and evaluation unit configured for determining an externally referenced orientation of the observation device depending on a measured magnetic field direction and a measured gravitational field direction and with application of an algorithmic disturbance suppression, for which compensation parameters—relating to a compensation of local magnetic field disturbance influences—are stored, further comprising: a video tracking system for recording an image sequence and for deriving—carried out on the basis of the image sequence—orientation changes of the observation device, and in that the control and evaluation unit is configured in such a way that the determination of the externally referenced orientation is furthermore influenced by orientation changes derived by the video tracking system, in particular by virtue of the fact that the stored compensation parameters are based, inter alia, on orientation changes derived by the video tracking system.