Answer the following question given this paragraph: 

Many extremely interesting objects can’t be seen with the unaided eye. Astronomers use telescopes to see objects at wavelengths all across the electromagnetic spectrum. Some very hot stars emit light primarily at ultraviolet wavelengths. There are extremely hot objects that emit X-rays and even gamma rays. Some very cool stars shine mostly in the infrared light wavelengths. Radio waves come from the faintest, most distant objects.


Q: What devices do astronomers use to see objects at wavelengths all across the electromagnetic spectrum?


A:
telescopes