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Primary lens: The objective of a refracting telescope. Primary mirror: The objective of a reflecting telescope. Corrector plate: A full aperture negative lens placed before a primary mirror designed to correct the optical aberrations of the mirror. Schmidt corrector plate: An aspheric-shaped corrector plate used in the Schmidt telescope.
Celestron was the first large scale commercial manufacturer of the Schmidt-Cassegrain telescope, introducing its "C8" 8" diameter 2032 mm focal length, ƒ10 telescope in 1970. [7] The primary innovation Celestron/Tom Johnson devised was a method to produce Schmidt corrector plates using a vacuum to pull the glass blanks into a pre-shaped curve ...
Tour guide points out the double Finderscope on the 24.5 inch Cassegrain Telescope at the Goldendale Observatory State Park. A finderscope is an accessory sighting device used in astronomy and stargazing, typically a small auxiliary refracting telescope/monocular mounted parallelly on a larger astronomical telescope along the same line of sight.
A 6-inch (15 cm) Newtonian reflector built by a school student on display at Stellafane Although the types of telescopes that amateurs build vary widely, including Refractors, Schmidt–Cassegrains and Maksutovs, the most popular telescope design is the Newtonian reflector, [3] described by Russell W. Porter as "The Poor Man's Telescope".
When Edmund Scientific introduced the telescope in 1976 they called it "The Edmund Wide-Field Telescope" with a Part Number "2001" [5] Edmund had a public contest which ran until November 15, 1976, to come up with a name. [6] The winning name was "Astroscan 2001". The "2001" part of the name was dropped over time.
For an equatorial GoTo telescope mount, the user must align the mount by hand with either the north celestial pole or the south celestial pole. Assuming the user is accurate in the alignment, the mount points the telescope to a bright star, asking the user to center it in the eyepiece.
The telescope tubes of compact binoculars can often be folded closely to each other to radically reduce the binocular's volume when not in use, for easy carriage and storage. Many tourist attractions have installed pedestal-mounted, coin-operated binocular tower viewers to allow visitors to obtain a closer view of the attraction.
Typical accessories for telescopic sights are: Lens hood is a tubular extension mounted on the objective and/or ocular ends to shade light and reduce/eliminate glare . The lens hood mounted on the eyepiece , often called an eyecup , is often made from corrugated silicone rubber for resting against the user's eye socket, and can also help avoid ...