Newton's Reflecting Telescope Essays
Refracting Telescope - WriteWork
Celestron PowerSeeker 114EQ 45 - 225X Reflector Telescope opens up the wonders of the universe to the aspiring astronomer. Amateur astronomy is a great hobby you can enjoy year-round, and Celestron's PowerSeeker Telescopes are the ideal choice for affordable stargazing enjoyment! PowerSeeker Scopes are quick and easy to set up, even for the novice... no tools required! Their sturdy Equatorial mounts are perfect for tracking objects across the night sky, meaning these Telescopes shine for moon- and planet-watching.
therefore he constructed a reflecting telescope
In a Newtonian reflecting telescope, light rays from distant objects, which are essentially parallel (because they come from so far away), strike the concave main mirror at the same angle. The rays are then reflected back up through the telescope tube toward the focal point. However, before they reach the focal point, they strike a secondary, flat mirror that is tilted at a 45-degree angle. The secondary mirror diverts the light out through a hole in the side of the tube. The eyepiece lens then focuses the light. This produces a magnified image. Also, the image appears much brighter than it does to the naked eye because the mirror gathers and concentrates the light.
History of the telescope - Wikipedia
Among the catadioptrics, the Maksutov Cassegrain has justifiably earned a solid reputation as an excellent high resolution telescope. The Maksutov design combines a spherical mirror with a longer native focal length (slower f/3 relative aperture) than a typical Schmidt Cassegrain (f/2) with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly spherically symmetrical. The negative lens is usually full diameter and placed at the entrance pupil of the telescope (commonly called a corrector plate or meniscus corrector shell). The design corrects the problems of off-axis aberrations such as coma found in reflecting telescopes while also correcting for chromatic aberration. It was patented in 1941 by Russian optician Dmitri Dmitrievich Maksutov after a five year spell of careful ray tracing and prototype building, which culminated in the first working model produced in the autumn of the same year. He based his design on the idea behind the Bernard Schmidt’s camera, which used the spherical errors of a negative lens to correct the opposite errors inherent of a spherical primary mirror. Because the design utilises all-spherical elements, it greatly aids in mass fabrication.
This reflecting telescope which had a 60-centimetre ..
Despite these innovations it is arguably the range produced by Orion (USA) and SkyWatcher that has made most heads turn in the Maksutov camp in recent years. Following fast on the heels of the better established small companies, Synta churned out an exciting suite of Gregory Maks in the 90mm – 180mm range which could be purchased as complete packages including a mount or as optical tube assemblies. Over the last six months or so, I have been carefully evaluating an Orion re-branded version of Synta’s 180mm model – the telescope that has really opened my eyes to the tremendous versatility of the Maksutov design as a visual instrument.