Astroscan
The Astroscan was a wide-field 4⅛" clear-inch (105mm) diameter reflecting telescope, originally produced by the Edmund Scientific Corporation, that was for sale from 1976 to 2013. Design The Astroscan had a Newtonian reflector layout with a 4⅛" clear-inch (105mm) diameter f/4.2 aluminized and overcoated borosilicate glass parabolic primary mirror with a focal length of 17½ inches (445mm). The telescope's secondary mirror was mounted on a flat optical window at the front of the tube. Edmund designer Norman Sperling and optical engineer Mike Simmons came up with the basic design and Peter Bressler Design Associates did the detailed work on this simple introductory telescope. Rather than using a more traditional equatorial or altazimuth mount the Astroscan features a spherical housing around the primary reflector which sat in a cast aluminum cradle. The design was durable and allowed for simple operation by novice amateur astronomers; it won an Industrial Design Award in 1976. ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Edmund Scientific Corporation
Edmund Scientific Corporation, based in Barrington, New Jersey, was founded in 1942 as a retailer of surplus optical parts like lenses. It later branched out into complete systems like telescopes and microscopes, and in the 1960s, a wide variety of science toys and kits. Through the 1970s and 80s they were best known for their mail order sales and associated catalogs, although they also maintained a retail presence at their factory store. In 1984, the company split into Edmund Scientific and Edmund Industrial Optics, the latter taking over their optical manufacturing. Later known simply as Edmund Optics, the commercial side of the company continued to expand and now has a multinational presence. In 2001, the two companies were purchased by Boreal Science, which was in turn purchased by VWR International. Many of the science toys and kits are currently offered by the online retailer Scientifics Direct. Among the company's best-known products were the Astroscan reflector telesc ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Infinite-axis Telescope
An infinite-axis telescope is a telescope that can move freely in all directions. Such telescopes can be mechanically simple hand-guided versions with the mounting serving only to carry the weight of the telescope although there are equatorial versions. Types An example of this type of telescope was the late 17th century "Air" or "Aerial telescope", which was a very long focal length refracting telescope that did not use a tube. In these telescopes a hand held eyepiece and an objective lens, objective mounted on a ball joint were connected by a string; the observer kept the string tight and moved the eyepiece to aim the telescope. Another example of an infinite-axis telescope is a ball-in-cup mounted telescope, also called a spherical-mounted telescope. The first Newtonian telescope was mounted in this way; the ball was held in place by wrought iron springs. Another type uses a bowling balls as a mount axis. There are modern commercial and Amateur telescope making, amateur moun ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Norman Sperling
__NOTOC__ Norman Sperling (born March 19, 1947) is an author, editor, publisher, teacher, and telescope designer living in San Mateo, California. Sperling received a BA from Michigan State University after graduating from Montgomery Blair High School in Silver Spring, Maryland. He followed that with an MA in History of Science from the University of California, Berkeley. He has taught astronomy and related courses at Sonoma State University, California State University, Hayward, UC Berkeley, and San Francisco State University. Publisher and author Sperling founded astronomical supplier and publisher Everything in the Universe in 1977. He has been assistant editor for Sky & Telescope magazine and was science editor for AltaVista. , Sperling is the editor and publisher of the Journal of Irreproducible Results, a science humor magazine. He authored ''What Your Astronomy Textbook Won't Tell You'' and ''Any Parent's Recipe for Great Baseball'' He edited and published John Dobs ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Acrylonitrile Butadiene Styrene
Acrylonitrile butadiene styrene (ABS) (chemical formula (C8H8)''x''·(C4H6)''y''·(C3H3N)''z'' is a common thermoplastic polymer. Its glass transition temperature is approximately . ABS is amorphous and therefore has no true melting point. ABS is a terpolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. The proportions can vary from 15% to 35% acrylonitrile, 5% to 30% butadiene and 40% to 60% styrene. The result is a long chain of polybutadiene crisscrossed with shorter chains of poly(styrene-co-acrylonitrile). The nitrile groups from neighboring chains, being polar, attract each other and bind the chains together, making ABS stronger than pure polystyrene. The acrylonitrile also contributes chemical resistance, fatigue resistance, hardness, and rigidity, while increasing the heat deflection temperature. The styrene gives the plastic a shiny, impervious surface, as well as hardness, rigidity, and improved processing ease. The polybutadiene ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Kickstarter
Kickstarter is an American public benefit corporation based in Brooklyn, New York, that maintains a global crowdfunding platform focused on creativity. The company's stated mission is to "help bring creative projects to life". As of July 2021, Kickstarter has received $6.6 billion in pledges from 21 million backers to fund 222,000 projects, such as films, music, stage shows, comics, journalism, video games, board games, technology, publishing, and food-related projects. People who back Kickstarter projects are offered tangible rewards or experiences in exchange for their pledges. This model traces its roots to subscription model of arts patronage, where artists would go directly to their audiences to fund their work. History Kickstarter launched on April 28, 2009, by Perry Chen, Yancey Strickler, and Charles Adler. '' The New York Times'' called Kickstarter "the people's NEA". '' Time'' named it one of the "Best Inventions of 2010" and "Best Websites of 2011". Kickstarter r ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Altazimuth Mount
An altazimuth mount or alt-azimuth mount is a simple two- axis mount for supporting and rotating an instrument about two perpendicular axes – one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth (compass bearing) of the pointing direction of the instrument. Rotation about the horizontal axis varies the altitude angle (angle of elevation) of the pointing direction. These mounts are used, for example, with telescopes, cameras, radio antennas, heliostat mirrors, solar panels, and guns and similar weapons. Several names are given to this kind of mount, including altitude-azimuth, azimuth-elevation and various abbreviations thereof. A gun turret is essentially an alt-azimuth mount for a gun, and a standard camera tripod is an alt-azimuth mount as well. Astronomical telescope altazimuth mounts When used as an astronomical telescope mount, the biggest advantage of an alt-azimuth mount is the simplicity of its mechanical design. The primary ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Science Kit And Boreal Laboratories
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek ma ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Field Of View
The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans and animals In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. Adelman & B.H. Smith (Eds): ''Encyclopedia of Neuroscience''; 3rd edition, on CD-ROM. El ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Degree (angle)
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane angle in which one full rotation is 360 degrees. It is not an SI unit—the SI unit of angular measure is the radian—but it is mentioned in the SI brochure as an accepted unit. Because a full rotation equals 2 radians, one degree is equivalent to radians. History The original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. Ancient astronomers noticed that the sun, which follows through the ecliptic path over the course of the year, seems to advance in its path by approximately one degree each day. Some ancient calendars, such as the Persian calendar and the Babylonian calendar, used 360 days for a year. The use of a calendar with 360 days may be related to the use of sexagesimal numbers. Anothe ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Eyepiece
An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks through the device. The objective lens or mirror collects light and brings it to focus creating an image. The eyepiece is placed near the focal point of the objective to magnify this image. The amount of magnification depends on the focal length of the eyepiece. An eyepiece consists of several "lens elements" in a housing, with a "barrel" on one end. The barrel is shaped to fit in a special opening of the instrument to which it is attached. The image can be focused by moving the eyepiece nearer and further from the objective. Most instruments have a focusing mechanism to allow movement of the shaft in which the eyepiece is mounted, without needing to manipulate the eyepiece directly. The eyepieces of binoculars are usually permanently mounted in the binocular ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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John Wiley And Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |