A reflecting telescope forms an image using a single curved mirror, or a combination of curved mirrors, to reflect light. Isaac Newton invented it in the seventeenth century as an alternative to the refracting telescope, which at the time suffered from severe chromatic aberration. Reflecting designs introduce their own kinds of optical aberration, but they allow for much larger objective diameters, which is why almost all major research telescopes in astronomy today are reflectors. Many variant designs exist, some adding extra optical elements to improve image quality or to place the image somewhere mechanically convenient, and because they rely on mirrors the design is sometimes called a catoptric telescope. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
Facts
YearSourced to the subject's own accountIsaac Newton own working telescope, built in 1668, five years after James Gregory published an unbuilt reflecting telescope design in 1663. SignificanceSourced to the subject's own accountThe reflecting telescope avoided the chromatic aberration of lens-based refracting telescopes by forming its image with a mirror, a principle behind nearly every large research telescope built since. 1 Connections
Associated With
Borosilicate glass, whose low thermal expansion keeps a figure stable, was used for large reflecting-telescope mirror blanks such as the Pyrex mirror of the 200-inch Hale telescope.
Sources
1. Reflecting telescope (Wikipedia)
WikipediaHistory section, para 2
Isaac Newton in 1668 built his own reflecting telescope, which is considered the first reflecting telescope, as previous designs were never put into practice or ended in failure when attempted.
History section, para 1, advantages of mirrors
The potential advantages of using parabolic mirrors, primarily reduction of spherical aberration with no chromatic aberration, led to many proposed designs for reflecting telescopes.
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