"The early timeline of telescopes shows that many advances were made even before we advanced into what we think of as modern times. Since the 1800's, so many advancements were made in the field of producing telescopes that documenting each and every one would be able to fill up pages and pages of text."
"It was at this point in the telescope timeline that Sir Isaac Newton began to change telescope lenses so that there would be no chromatic aberration. He also found a way to add mirrors to improve images without having to make the telescope longer. This appealed to people as Newton's telescope was small but had the same power as the larger ones."

1609 - Galileo first invented the telescope. Though it was crude, it still did the trick and allowed him to look into space for the very first time other than with the naked eye. Galileo's telescope was a reflecting one causing light to bounce off a mirror when looked at through a lens.

Mid-1600's - Johannes Keplar came up with the idea of a refracting telescope that would widen the field of view as well as improve the quality of the image. He did this by changing the shape and the placement of the lenses, but doing this caused little circles of color that would surround bright objects - chromatic aberration.

Late 1600's - As the century began to draw to a close, telescope makers were realizing that with a bigger lens, you could see much more. With a bigger lens, the telescope had to be bigger to accommodate it. Eventually, telescopes were being built that we as long as a hundred feet!

Mid-1800's - The first photographic telescope is introduced. John William Draper found a way to focus the Moon's image on a light-sensitive photographic plate. He used a clockwork device to keep the light in place even as the Earth rotated and the moon moved through the sky. After an exposure of 20 minutes, he had taken the first ever photograph of the moon! After the introduction of the photographic telescope came about, we were able to see the skies up close and personal. And what a great accomplishment!

Source: Monocular Telescope