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The European Southern Observatory (ESO) has been able to capture telescopic images at visible wavelengths from the ground that are sharper than those from the NASA/ESA Hubble Space Telescope. The ground-based Very Large Telescope (VLT) has used an adaptive optics mode called laser tomography to capture images of distant objects in the solar system. The laser tomagraphy compensates for atmospheric turbulence resulting in more detail than anything prior. It works by stimulating sodium ions in the upper atmosphere using two pairs of lasers to calculate the turbulence and adjusting a deformable secondary mirror thousands of times per second in response.
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Laser Tomography Adaptive Optics Enable Sharper Telescopic Imaging
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(Score: 1, Interesting) by Anonymous Coward on Friday July 27 2018, @08:06PM
Generally, no. If you have sufficiently high signal-to-noise (i.e., a bright scene) and you can thus use sufficiently short exposure times that freeze the atmospheric turbulence, then there are algorithms you can do to correct it (if your aperture is small enough, you don't have to correct for it because the image will be in focus, but laterally shifted on your camera; if your aperture is large enough, you can correct for it but you need additional instrumentation to measure it (e.g., a Shack-Hartmann sensor)).
This issue you have is these telescopes need to use long exposure times were the atmosphere randomly moves the image around on your camera that averages out to a Gaussian smear. You need the deformable mirror to hold an in-focus image on the same pixels during the exposure. Besides, if you are going through the process of adding several of these lasers and detectors to measure the wavefronts of the light coming down to the ground, the deformable mirror actually isn't the driving cost. These mirrors are generally not very large.