Is it possible to 3D print a mirror to create a high quality telescope?

Question

Is it possible to 3D print a mirror with todays available materials?If so, would there be a reduction in image quality?

Answer 1

The short answer is no, unless your machine can guarantee tolerances at the nanometer level. A basic Newtonian reflector, irrespective of the size, requires that it's primary mirror be parabolic in curvature to within 1/4 wavelength of light to achieve the theoretical resolution for its aperture; this is known as the Reyleigh criterion. 1/4 wavelength of yellow-green light is on the 1/10 micron scale (1 micron is 1 millionth of a meter or 10^-6 meters), so your printer would have to be accurate and reliable to within 1/10 of that or 10^-7 meters.

And how do you even print using glass or a hard, low-expansion surface?