Finally, what of Alberti's window in this "postperspectival age"? Let me briefly allude to the recent technology of "digital image processing" that has almost entirely replaced conventional photography in astronomical observatories, expecially for the recording the most distant galaxies and quasars. This ability is the result of a remarkable postage-stamp-sized silicon chip known as teh CCD, or "charged-coupled device," which can be attached to a telescope to make it into a camera, and which acts like a photographic plate. Rather than being coated with light-sensitive emulsion, its surface is composed of millions of tin electronic "pixels" arranged in a rectangular grid.
Have we here the ultimate heir to Alberti's window? Just as the Renaissance artist transferred his earthly subject, square by square as seen through the gridded veil, onto his smaller-scaled picture surface, so the CCD collects cosmic light through the telescope, pixel by pixel, and then converts each photon impulse into a digitized electronic signal and sends it to a television monitor. Celestial bodies are perceived and revealed against the deep-sky background by the luminosity fluctuations and changes in brightness recorded by the individual pixel across the CCD grid. These digitized encodings can then be translated into computerized colors. Since the actual hues of the celestial subject remain invisible, however the image processor (as the CCD artist is now professionally called), even though equipped with spectrum sensors and chromatic filters, must still make decisions based on aesthetic preference just as do modern artists - or one might even say like medieval artists trying to comprehend the ineffable colors of the heavenly empryean.
The Mirror, the Window and the Telescope, How Renaissance Linear Perspective Changed Our Vision of the Universe, by Samuel Y. Edgerton (pp 171-172)