It's a fairly simple question (at least in my layman's mind). Can a radio telescope that has no mirrors or lenses to capture visible light (to human eyes) still produce imagery like an optical telescope such as the Hubble? I'm talking just ROYGBIV light (no infrared or UV).
Can a radio telescope that has no mirrors or lenses to capture visible light (to human eyes) still produce imagery like an optical telescope such as the Hubble?
Of course, either via false color or pseudocolor. A false color radio image maps various frequencies (typically three) in a multispectral radio image to visible colors. A pseudocolor radio image maps various intensities in a single spectrum gray scale radio image to visible colors. The same techniques are also used for gamma, X-ray, UV, IR, and microwave imagery. We can't see in those frequencies, so something needs to be done to the captured imagery to make them visible to us.
If the question is asking whether a radio telescope can be used to capture visible light, the answer is no. I'll start with the receiver. It's designed to capture long wavelength radiation. Photons in the visible spectrum will have minimal, if any, impact on a radio telescope receiver.
An even bigger problem with some radio telescopes is depicted below.
The above is the Haystack Radio Telescope at the Haystack Observatory in Westford, Massachusetts. The radome protects the telescope against weather, but also hides the antenna from optical light. A couple of other radio telescopes at the Haystack Observatory show yet another problem:
The fixed zenith telescope antenna in the foreground and the fully movable telescope antenna in the background are made of a wire mesh, making them see-thru in the visible portion of the spectrum. This wire mesh construction is quite common for long wavelength radio antennae because it allows the wind to blow through it. Shorter wavelength radio antennae are more likely to be solid, but those are oftentimes painted.
A wire mesh with wires separated by centimeters is very smooth to a meter long radio wave, as solid surface smooth at the millimeter level to a centimeter long radio wave. A surface with millimeter-scale roughness would make for an extremely lousy optical mirror. There is no reason to make a radio telescope antenna smooth to the visible portion of the spectrum, and there are many millions of reasons (i.e., many millions of dollars) not to do so.
Here are images produced with radio waves in RGB, but they are frequency-inaccurate. YES, Radio telescopes can produce imagery... NO, radios are not in the visible range, otherwise a talky walky areal would glow like a lamp when it transmits information. No, Radio antenna don't capture photons electrically and it is their voltage change which is measured, they can only get hot and malfunction from light.
The question is mystifying... You must read about electromagnetic spectrum energy!!! it's simple!! it is the source of all collected astronomy data and studies. It's like subtraction and division in maths, electromagnetic spectrum is fundamental. If you mix up photons and radio waves, it's like you are mixing subtractions and divisions.
The colors here are red to green based on real radio wave length according to the researcher, however i think it's a compilation of multiple images of different radio periods. source is 70-230mhz = 1.2meters to 4meters
The answer is either "no, of course not," or "yes, in a pathological sense." A radio "telescope" captures photons which are capable of forcing electromagnetic responses in metal -- which is to say, the induced voltage caused by an E-M field. The statistical odds of a visible-range photon causing an induced signal of detectable level in a metal antenna are ridiculuously small.