My question is about using an IR thermometer for measuring the temprature of a blackbody that emitts a spectrum that peaks somewhere in the visible region. I think since these kind of thermometers measures the amount of infrared radiation emitted by the object, they can only determine the temprature of objects of moderate temprature that radiate in the mid-infrared region or colder ones that radiate in the far-infrared. So, does this mean we can't use them to determine the temprature of a blackbody that is about the same temprature as a star? And what happens if we use them to measure such hot objects? Do we need a spectrometer for measuring the temprature of a blackbody which is extremely hot? (I've read this in an old thread, not sure if it is true) I appreciate any clarification.