Depends what you mean by "telescope" and "see".
Light is just a form of electromagnetic photons. To be visible, the photon has to be within a very narrow interval of wavelengths. If it is outside this range, it is still a photon of electromagnetic energy, but it is not visible to the human eye.
For example, the old version of film that we use to put in cameras and telescopes was sensible to ultraviolet light (invisible to the human eye because the wavelength is too short) in addition to visible light. In fact, if we did not want it on our images, we had to add a filter to block it out.
Modern CCD cameras, used in telescopes, are also sensible to infrared light (still photons, but this time, the wavelength is too long to be visible to the eye).
Astronomers will say that the camera (or the telescope using that camera) "sees" the infrared light.
Radio telescopes are simply telescopes that can see photons that have wavelengths so long, that we call them radio waves. They are still photons of electromagnetic energy. The only difference with photon of visible light is the wavelength.
Radio telescopes can see the Cosmic Microwave Background radiation (CMB radiation) and that is "light" that was emitted at the time when the universe became transparent.
Therefore, it is the furthest that we can ever see (because the universe was not transparent for photons, before that moment).
13.7 billion light-years.
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The CMB contains photons of all wavelengths, but the peak wavelength is in a region of the spectrum that we call microwave radio waves. Because of the expansion of space, this is the wavelength of the photons as we observe them today. When they were emitted, the peak photons (the ones we detect today as microwaves) were emitted as bright orange, almost yellow visible light.
Thus, when we see the CMB radiation, we are seeing "light" that now has the form of radio waves.
Light is just a form of electromagnetic photons. To be visible, the photon has to be within a very narrow interval of wavelengths. If it is outside this range, it is still a photon of electromagnetic energy, but it is not visible to the human eye.
For example, the old version of film that we use to put in cameras and telescopes was sensible to ultraviolet light (invisible to the human eye because the wavelength is too short) in addition to visible light. In fact, if we did not want it on our images, we had to add a filter to block it out.
Modern CCD cameras, used in telescopes, are also sensible to infrared light (still photons, but this time, the wavelength is too long to be visible to the eye).
Astronomers will say that the camera (or the telescope using that camera) "sees" the infrared light.
Radio telescopes are simply telescopes that can see photons that have wavelengths so long, that we call them radio waves. They are still photons of electromagnetic energy. The only difference with photon of visible light is the wavelength.
Radio telescopes can see the Cosmic Microwave Background radiation (CMB radiation) and that is "light" that was emitted at the time when the universe became transparent.
Therefore, it is the furthest that we can ever see (because the universe was not transparent for photons, before that moment).
13.7 billion light-years.
---
The CMB contains photons of all wavelengths, but the peak wavelength is in a region of the spectrum that we call microwave radio waves. Because of the expansion of space, this is the wavelength of the photons as we observe them today. When they were emitted, the peak photons (the ones we detect today as microwaves) were emitted as bright orange, almost yellow visible light.
Thus, when we see the CMB radiation, we are seeing "light" that now has the form of radio waves.