The invention relates to a condensing drum dryer (1) having a drum (2) for articles (4) to be dried, a drum (2) for the drum (2) ), process air channel (24), process air fan (27), heating / cooling system (14, 16, 18, 19, 25, 30) for process air (11), temperature sensor (21) and a control device (20). The temperature sensor (21) is an infrared telescope (21) and is arranged to simultaneously measure at least two monitored components (5, 14, 16, 18, 19, 24, 25, 27, 28, 30) thermal radiation. The invention also relates to a method for operating such a condensation tumble dryer (1).