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A copyscope is type of refracting telescope that can be made by hand rather than bought in which the objective lens comes from an old photocopy machine, hence the origin of the name. [1] The lenses usually come from defective or old photocopiers, allowing for the objective to be obtained for free or at a low cost.
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".
Openclipart, also called Open Clip Art Library, is an online media repository of free-content vector clip art.The project hosts over 160,000 free graphics and has billed itself as "the largest community of artists making the best free original clipart for you to use for absolutely any reason".
Some telescopes are classified by the task they perform; for example Solar telescopes are all designs that look at the Sun, Dobsonian telescopes are designed to be low cost and portable, Aerial telescopes overcame the optical shortcomings of 17th-century objective lenses, [1] etc.
If the right lens is inserted, so that the chosen distance roughly equals the distance of the drawing surface, both images can be viewed in good focus simultaneously. [ citation needed ] If white paper is used with the camera lucida , the superimposition of the paper with the scene tends to wash out the scene, making it difficult to view.
Have streak-free glasses for years to come with this mega-popular mega-kit. Includes one bottle of gentle, effective cleaner and a microfiber cloth — all made in the U.S.A.
A Schmidt corrector plate is an aspheric lens which corrects the spherical aberration introduced by the spherical primary mirror of the Schmidt or Schmidt–Cassegrain telescope designs. It was invented by Bernhard Schmidt in 1931, [ 6 ] although it may have been independently invented by Finnish astronomer Yrjö Väisälä in 1924 (sometimes ...