Device for measuring temperature without contact

A system for contactless temperature measurement of an object with the system having an infrared optical system with a finite focal length and an infrared detector, wherein an image of the detector is imaged by the optical system along an optical axis onto a measurement spot on the object in such a way that the image of the detector reduces from the optical system to a sharp point measurement spot and then enlarges, and with a sighting arrangement which identifies the outer limit of the measurement spot at all distances from the optical system, said system comprising:

• a light source for outputting a primary light beam along an optical axis;
• a beamsplitter for splitting said primary light beam into first and second component beams;
• first and second sighting elements disposed away from the optical axis and disposed to respectively intersect said first and second component beams;
• with said first sighting element for deflecting the first component beam obliquely toward the optical axis in a first plane including the optical axis and deflecting the first component in a first direction perpendicular to first plane and away from the optical axis;
• with said second sighting element for deflecting the first component beam obliquely toward the optical axis in a second plane including the optical axis and in a second direction perpendicular to said second plane away from the optical axis so that said first and second components intersect the limits of the measurement spot at all distances from the optical system.