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A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic ...
The Newtonian telescope, also called the Newtonian reflector or just a Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton, using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting ...
The telescope had a flat diagonal secondary mirror bouncing the light at a 90° angle to a Plano-convex eyepiece with a probable focal length of 4.5mm yielding his observed 35 times magnification. Newton said the telescope was 6.25 inches long; this matches the length of the instrument pictured in his monograph "Opticks".
The word was created from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing'. By 1626 knowledge of the telescope had spread to China when German Jesuit and astronomer Johann Adam Schall von Bell published Yuan jing shuo, (遠鏡說, Explanation of the Telescope) in Chinese and Latin. [43]
The first of these was the Hamiltonian telescope patented by W. F. Hamilton in 1814. The Schupmann medial telescope designed by German optician Ludwig Schupmann near the end of the 19th century placed the catadioptric mirror beyond the focus of the refractor primary and added a third correcting/focusing lens to the system.
A reflecting telescope by James Short; this English telescope maker produced almost 1400 Gregorian reflectors in the mid-1700s. Mobile versions were used to observe the Transit of Venus . List of largest optical telescopes in the 18th century includes various refractors and reflectors that were active some time between about 1699 to 1801.
The Ritchey–Chrétien telescope was invented in the early 1910s by American astronomer George Willis Ritchey and French astronomer Henri Chrétien. Ritchey constructed the first successful RCT, which had an aperture diameter of 60 cm (24 in) in 1927 (Ritchey 24-inch reflector).
In 1900, Grubb invented the reflector or "reflex" sight, [5] [6] a non-magnifying optical sight that uses a collimator to allow the viewer looking through the sight to see an illuminated image of a reticle or other pattern in front of them that stays in alignment with the device the sight is attached to (parallax free).