Recounts the quests of certain knights as they struggled to achieve specific virtues, including stories that involve dragons, witches, and enchanted mirrors, in a work that was dedicated to Elizabeth I. Author: Spenser, Edmund Series Title: Penguin Classics Publication Date: 1988/07/01 Binding Type: Paperback Language: English Depth: 2.00 Width: 5.25 Height: 7.75
This is a reproduction of a book published before 1923. This book may have occasional imperfectionssuch as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed worksworldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.++++The below data was compiled from various identification fields in the bibliographic record of this title. This data is provided as an additional tool in helping to ensure edition identification: ++++ Photomicrography Edmund Johnson Spitta Scientific Press, 1899 Science; Microscopes Microscopy; Photomicrography; Science / Microscopes Microscopy; Science / Optics Author: Spitta, Edmund Johnson Binding Type: Paperback Number of Pages: 204 Publication Date: 2011/09/07 Language: English Dimensions: 9.69 x 7.44 x 0.43 inches
High Quality Content by WIKIPEDIA articles In an optical instrument, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. Objectives can be single lenses or mirrors, or combinations of several optical elements. They are used in microscopes, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses. Author: Surhone, Lambert M./ Timpledon, Miriam T./ Marseken, Susan F. Binding Type: Paperback Number of Pages: 128 Publication Date: 2010/07/08 Language: English Dimensions: 5.98 x 9.01 x 0.30 inches
Optics gives a comprehensive and balanced account of traditional optics as well as some of the recent developments in this field while meeting the requirements of a course on optics meant for undergraduate students of science and engineering.
Celestron's innovative new EdgeHD telescopes are aplanatic Schmidt Cassegrain models designed to produce aberration-free images across a wide visual and photographic field of view. Celestron EdgeHD optics produce a focal plane more than three-times flatter than a standard Schmidt Cassegrain telescope...
Inspect Your Own Eye -- Check Contact Lenses -- Our precision radius mirror with front surface coating allows you to inspect your own eye by simply holding the mirror approximately two inches in front of your eye...
Pan: the smallest membrane deformable mirror
How to Buy a Telescope
Buying a first telescope for you or for someone else as a gift can be a bit tricky if you don’t know a lot about telescopes. This article will guide you through making the right choice based on price, performance, and what your astronomical goals are.
A telescope is a scientific optical instrument. It has lenses or mirrors in it that have to be carefully made to exacting specifications if it is to perform adequately as an astronomical instrument. This can cause problems when it comes to buying a lower priced and subsequently lower quality telescope because these telescopes can underperform or even not perform at all. In order to be guaranteed you will get high performing optics that give you good value for your money you should stick with one of the better known manufacturers of telescopes. I recommend you buy from Orion, Celestron, Meade, or Edmund Scientifics. There are many makers of telescopes that make outstanding telescopes but I have first hand knowledge of these and can vouch for their quality.
Most of these makers of telescopes sell them but you don’t need to buy directly from them. You can find telescopes from these makers on sale at many online sites or retail outlets. So you can stick with your favorite big retailer.
If you are buying a first telescope for a high school student or child your best choice is to buy a 60mm refractor telescope. This kind of telescope is sturdy, easy to use, easy to set, up and gives great performance in the hundred-dollar price range. This type of telescope is also very useful for terrestrial observations, which makes it versatile. I would vary from this rule of thumb if you are getting a telescope for someone that spends a lot of time hiking and camping and they are looking for something easily toted along. A 60mm refractor can be a bit impractical for camping and hiking because of its size. In this case I recommend you get either an astroscan from edmund scientifics or the backpack observatory from the Meade Corporation. Both these telescopes are a bit more expensive but much more compact and easy to tote around.
If you are buying a telescope for someone that knows a bit about astronomy or maybe already has a telescope you might consider sitting down with him or her and discussing needs and wants. Telescopes vary widely in price, style, type and ability and an amateur astronomer probably has some definite wants and goals. But as a rule of thumb for a person that already is interested in astronomy they probably are looking for a reflector or catadioptric telescope because these types of telescopes give significantly more light gathering power than the refractor when you weigh the price. A five-inch refractor telescope will cost you anywhere between three and four thousand dollars! Yet you can get a reflector or catadioptric with a massive eight or ten inch mirror for a few hundred dollars. This massive increase in size gives the amateur astronomer a significant improvement in what he or she can see in the night sky.
If you are looking to purchase something in a moderate price range (500-1,000 dollars) you should consider getting a catadioptric telescope in the Schmidt Cassegrain style. This type of telescope gives you superior performance, maximum light gathering power, and quality of instrument that will last you a lifetime. This kind of telescope now often comes with a motorized computer with a database of thousands of celestial object that allows you to find things at the touch of a button. It is also a folded optics telescope so it is compact and reasonably easy to tote around. They are suitcase sized and many of the leading manufacturers often make the suitcase to go with it.
In summary if you are buying for a child, teen, or first time telescope owner you should get a 60mm refractor because it is easy to use, easy to set up, durable and entry level priced around one hundred dollars. If you are buying a telescope for someone that is seriously interested in astronomy you should consider a reflector in the six-inch to ten-inch range. This will give you maximum light gathering power for your dollar in the range of three hundred to five hundred. If you are looking to buy something of heirloom quality that will give you a lifetime of superb quality you should consider an eight-inch catadioptric Schmidt-Cassegrain telescope which will cost between five-hundred and a thousand dollars.
About the Author
The author has been an amateur astronomer for many decades. Learn more about telescopes and astronomy by visiting his website at: The Joy of Telescopes and Astronomy
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