Both telescopes and microscopes have been with us for several hundred years now. The latter optical device has evolved by an enormous amount, and I have at home a stereo zoom microscope with a 7X zoom ratio. By contrast, I also have a telescope with which Isaac Newton would have felt right at home. The evolution of telescope designs has been very slow indeed.
Except for the rapid invention of window shades and Venetian blinds, shortly after Galileo started to popularize the first telescope, there have been very few developments related to this optical instrument. This is partly because astronomers tend to be very conservative types. They try to minimize the number of optical surfaces so as to avoid light loss, and are hesitant to build very expensive large telescopes, except in proven, traditional designs.
by David Shafer