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This is a list of United States Army fire control, and sighting material by supply catalog designation, or Standard Nomenclature List (SNL) group "F".The United States Army Ordnance Corps Supply Catalog used an alpha-numeric nomenclature system from about the mid-1920s to about 1958.
The A. C. Gilbert Company was an American toy company, once one of the largest in the world. Gilbert originated the Erector Set, which is a construction toy similar to Meccano in the rest of the world, and made chemistry sets, microscope kits, and a line of inexpensive reflector telescopes.
The model can then be used in a telescope control system to correct the pointing and tracking. Such errors are typically caused by mechanical or structural defects . For example, TPoint can analyze and compensate for systematic errors such as polar misalignment , mechanical and optical non-orthogonality, lack of roundness in telescope mounting ...
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.
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".
A telescope on an alt-azimuth GoTo mount. Note the keypad, resting on the platform between the tripod's legs, that is the telescope's hand control. Batteries are stored in the circular compartment just above the tripod. In this picture, the compartment is just above the hand control.
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.
People demonstrating a Schmidt–Cassegrain telescope at a sidewalk gathering. The Schmidt–Cassegrain design is very popular with consumer telescope manufacturers because it combines easy-to-manufacture spherical optical surfaces to create an instrument with the long focal length of a refracting telescope with the lower cost per aperture of a reflecting telescope.