An infrared telescope is a scientific instrument that observes celestial objects in the infrared region of the electromagnetic spectrum. It is also known as a thermal telescope, far-infrared telescope, or heat telescope. The word "infrared" signifies the specific wavelength of light detected by the telescope, which falls between the visible and microwave bands. The different names for the infrared telescope refer to the various wavelengths of light they detect, from short wavelengths to long. These synonyms are useful for distinguishing between the different types of infrared telescopes used for astronomical observations, including those specialized for planetary science, star formation, and cosmology research.