Edmund Anscombe — Infobox Architect name=Edmund Anscombe nationality= English/New Zealander birth date= birth date|1874|2|8|mf=y birth place=Lindfield, West Sussex, England death date=death date and age|1948|10|9|1874|2|8|mf=y death place=Wellington, New Zealand… …   Wikipedia

End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

In 1942 amateur photographer Norman W. Edmund found it hard to find lenses he needed for his hobby. This led him to advertise lenses for sale in photography magazines. It was so successful he founded "'Edmund Salvage Corporation.'" It soon changed its name to Edmund Scientific and made its name with ads in publications like "Scientific American" as a supplier of chipped lenses, war-surplus optics, and low cost scientific gadgetry. Its advertisements caught the attention of hobbyists, amateur astronomers, high school students, and cash-strapped researchers. War surplusEdmund Scientific was part of the post-World War II "war surplus" phenomenon, when the U.S. government sold off large quantities of materials. "Army and Navy Stores" were a national phenomenon and originally sold military-surplus clothing. Surplus electronics found an outlet in dozens of shops, in New York City's "Radio Row" and elsewhere. A few issued catalogs and developed national mail-order businesses. Edmund was, however, the only widely-known supplier of surplus optics.The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

The image recorded by a photographic film or image sensor is always a real image and is usually inverted. When measuring the height of an inverted image using the cartesian sign convention (where the x-axis is the optical axis) the value for hi will be negative, and as a result M will also be negative. However, the traditional sign convention used in photography is "real is positive, virtual is negative".[1] Therefore, in photography: Object height and distance are always real and positive. When the focal length is positive the image's height, distance and magnification are real and positive. Only if the focal length is negative, the image's height, distance and magnification are virtual and negative. Therefore, the photographic magnification formulae are traditionally presented as[2]

Astroscan — The Astroscan is a wide field Newtonian reflector telescope produced by the Edmund Scientific Company. It was designed by Norman Sperling and Mike Simmons to be used as an introductory telescope. [Cite web | title = About Norm Sperling |… …   Wikipedia

For a good quality telescope operating in good atmospheric conditions, the maximum usable magnification is limited by diffraction. In practice it is considered to be 2× the aperture in millimetres or 50× the aperture in inches; so, a 60 mm diameter telescope has a maximum usable magnification of 120×.[citation needed]

where ε 0 {\textstyle \varepsilon _{0}} is the angle subtended by the object at the front focal point of the objective and ε {\textstyle \varepsilon } is the angle subtended by the image at the rear focal point of the eyepiece.

The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

War surplusEdmund Scientific was part of the post-World War II "war surplus" phenomenon, when the U.S. government sold off large quantities of materials. "Army and Navy Stores" were a national phenomenon and originally sold military-surplus clothing. Surplus electronics found an outlet in dozens of shops, in New York City's "Radio Row" and elsewhere. A few issued catalogs and developed national mail-order businesses. Edmund was, however, the only widely-known supplier of surplus optics.The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Mark Trueblood — is an American engineer and astronomer. He is noted for early pioneering work in the development of robotic telescopes, especially as the author of several articles and two books on the subject, including Microcomputer Control of Telescopes and… …   Wikipedia

The telescope is focused correctly for viewing objects at the distance for which the angular magnification is to be determined and then the object glass is used as an object the image of which is known as the exit pupil. The diameter of this may be measured using an instrument known as a Ramsden dynameter which consists of a Ramsden eyepiece with micrometer hairs in the back focal plane. This is mounted in front of the telescope eyepiece and used to evaluate the diameter of the exit pupil. This will be much smaller than the object glass diameter, which gives the linear magnification (actually a reduction), the angular magnification can be determined from

With d i {\textstyle d_{\mathrm {i} }} being the distance from the lens to the image, h i {\textstyle h_{\mathrm {i} }} the height of the image and h o {\textstyle h_{\mathrm {o} }} the height of the object, the magnification can also be written as:

Working distance (WD): object to lens distance where the image is at its sharpest focus. Depth of Field (DoF): maximum range where the object appears to be in ...

The maximum angular magnification (compared to the naked eye) of a magnifying glass depends on how the glass and the object are held, relative to the eye. If the lens is held at a distance from the object such that its front focal point is on the object being viewed, the relaxed eye (focused to infinity) can view the image with angular magnification

thenBy. Creates a comparator comparing values after the primary comparator defined them equal. It uses the function to transform value to a Comparable instance ...

With any telescope, microscope or lens, a maximum magnification exists beyond which the image looks bigger but shows no more detail. It occurs when the finest detail the instrument can resolve is magnified to match the finest detail the eye can see. Magnification beyond this maximum is sometimes called "empty magnification".

For example, the mean angular size of the Moon's disk as viewed from Earth's surface is about 0.52°. Thus, through binoculars with 10× magnification, the Moon appears to subtend an angle of about 5.2°.

If instead the lens is held very close to the eye and the object is placed closer to the lens than its focal point so that the observer focuses on the near point, a larger angular magnification can be obtained, approaching

Early historyIn 1942 amateur photographer Norman W. Edmund found it hard to find lenses he needed for his hobby. This led him to advertise lenses for sale in photography magazines. It was so successful he founded "'Edmund Salvage Corporation.'" It soon changed its name to Edmund Scientific and made its name with ads in publications like "Scientific American" as a supplier of chipped lenses, war-surplus optics, and low cost scientific gadgetry. Its advertisements caught the attention of hobbyists, amateur astronomers, high school students, and cash-strapped researchers. War surplusEdmund Scientific was part of the post-World War II "war surplus" phenomenon, when the U.S. government sold off large quantities of materials. "Army and Navy Stores" were a national phenomenon and originally sold military-surplus clothing. Surplus electronics found an outlet in dozens of shops, in New York City's "Radio Row" and elsewhere. A few issued catalogs and developed national mail-order businesses. Edmund was, however, the only widely-known supplier of surplus optics.The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

The image magnification along the optical axis direction M L {\displaystyle M_{L}} , called longitudinal magnification, can also be defined. The Newtonian lens equation is stated as f 2 = x 0 x i {\displaystyle f^{2}=x_{0}x_{i}} , where x 0 = d 0 − f {\textstyle x_{0}=d_{0}-f} and x i = d i − f {\textstyle x_{i}=d_{i}-f} as on-axis distances of an object and the image with respect to respective focal points, respectively. M L {\displaystyle M_{L}} is defined as

where M o {\textstyle M_{\mathrm {o} }} is the magnification of the objective and M e {\textstyle M_{\mathrm {e} }} the magnification of the eyepiece. The magnification of the objective depends on its focal length f o {\textstyle f_{\mathrm {o} }} and on the distance d {\textstyle d} between objective back focal plane and the focal plane of the eyepiece (called the tube length):

Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

In the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Measuring the actual angular magnification of a telescope is difficult, but it is possible to use the reciprocal relationship between the linear magnification and the angular magnification, since the linear magnification is constant for all objects.

Optical magnification is the ratio between the apparent size of an object (or its size in an image) and its true size, and thus it is a dimensionless number. Optical magnification is sometimes referred to as "power" (for example "10× power"), although this can lead to confusion with optical power.

With an optical microscope having a high numerical aperture and using oil immersion, the best possible resolution is 200 nm corresponding to a magnification of around 1200×. Without oil immersion, the maximum usable magnification is around 800×. For details, see limitations of optical microscopes.

*Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Typically, magnification is related to scaling up visuals or images to be able to see more detail, increasing resolution, using microscope, printing techniques, or digital processing. In all cases, the magnification of the image does not change the perspective of the image.

The longitudinal magnification is always negative, means that, the object and the image move toward the same direction along the optical axis. The longitudinal magnification varies much faster than the transverse magnification, so the 3-dimensional image is distorted.

Small, cheap telescopes and microscopes are sometimes supplied with the eyepieces that give magnification far higher than is usable.

M = d i d o = h i h o = f d o − f = d i − f f {\displaystyle {\begin{aligned}M&={d_{\mathrm {i} } \over d_{\mathrm {o} }}={h_{\mathrm {i} } \over h_{\mathrm {o} }}\\&={f \over d_{\mathrm {o} }-f}={d_{\mathrm {i} }-f \over f}\end{aligned}}}

where f {\textstyle f} is the focal length, d o {\textstyle d_{\mathrm {o} }} is the distance from the lens to the object, and x 0 = d 0 − f {\textstyle x_{0}=d_{0}-f} as the distance of the object with respect to the front focal point. A sign convention is used such that d 0 {\textstyle d_{0}} and d i {\displaystyle d_{i}} (the image distance from the lens) are positive for real object and image, respectively, and negative for virtual object and images, respectively. f {\textstyle f} of a converging lens is positive while for a diverging lens it is negative.

References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

For real images, M {\textstyle M} is negative and the image is inverted. For virtual images, M {\textstyle M} is positive and the image is upright.

* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Magnification figures on pictures displayed in print or online can be misleading. Editors of journals and magazines routinely resize images to fit the page, making any magnification number provided in the figure legend incorrect. Images displayed on a computer screen change size based on the size of the screen. A scale bar (or micron bar) is a bar of stated length superimposed on a picture. When the picture is resized the bar will be resized in proportion. If a picture has a scale bar, the actual magnification can easily be calculated. Where the scale (magnification) of an image is important or relevant, including a scale bar is preferable to stating magnification.

Ópticas rosario

A different interpretation of the working of the latter case is that the magnifying glass changes the diopter of the eye (making it myopic) so that the object can be placed closer to the eye resulting in a larger angular magnification.

United Kingdom — a kingdom in NW Europe, consisting of Great Britain and Northern Ireland: formerly comprising Great Britain and Ireland 1801 1922. 58,610,182; 94,242 sq. mi. (244,100 sq. km). Cap.: London. Abbr.: U.K. Official name, United Kingdom of Great… …   Universalium

in which f o {\textstyle f_{\mathrm {o} }} is the focal length of the objective lens in a refractor or of the primary mirror in a reflector, and f e {\textstyle f_{\mathrm {e} }} is the focal length of the eyepiece.

HMW110 and TMW110 transmitters can be ordered either with a cable gland with screw terminal wiring, or with an M12 connector (4-pin male).

As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

M = − d i d o = h i h o {\displaystyle M=-{d_{\mathrm {i} } \over d_{\mathrm {o} }}={h_{\mathrm {i} } \over h_{\mathrm {o} }}}

Óptica Gallo

*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

The magnification of the eyepiece depends upon its focal length f e {\textstyle f_{\mathrm {e} }} and is calculated by the same equation as that of a magnifying glass (above).

List of Duke University people — This list of Duke University people includes alumni, faculty, presidents, and major philanthropists of Duke University, which includes three undergraduate and ten graduate schools. The undergraduate schools include Trinity College of Arts and… …   Wikipedia

Europtica

Edmund — may refer to:People or characters with Edmund as the full name: *Edmund I of England *Edmund II of England *St. Edmund of East Anglia *St. Edmund Rich, also known as Edmund of Abingdon *Edmund I of Scotland *Edmund of Sicily *Eadmund of Durham… …   Wikipedia

Opticadh conference

2005516 — However, the beam splitters are not identical; they should be placed according to their labels, with the laser beam hitting the mirrored side ...

In 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

For optical instruments with an eyepiece, the linear dimension of the image seen in the eyepiece (virtual image at infinite distance) cannot be given, thus size means the angle subtended by the object at the focal point (angular size). Strictly speaking, one should take the tangent of that angle (in practice, this makes a difference only if the angle is larger than a few degrees). Thus, angular magnification is given by:

Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Top 10 entry-level jobs in engineering · 1. Electrical engineer · 2. Mechanical engineer · 3. Process engineer · 4. Design engineer · 5. Software engineer · 6. Civil ...

M A = 1 M = D O b j e c t i v e D R a m s d e n . {\displaystyle M_{\mathrm {A} }={1 \over M}={D_{\mathrm {Objective} } \over {D_{\mathrm {Ramsden} }}}\,.}

For real images, such as images projected on a screen, size means a linear dimension (measured, for example, in millimeters or inches).

Edmund Scientific was part of the post-World War II "war surplus" phenomenon, when the U.S. government sold off large quantities of materials. "Army and Navy Stores" were a national phenomenon and originally sold military-surplus clothing. Surplus electronics found an outlet in dozens of shops, in New York City's "Radio Row" and elsewhere. A few issued catalogs and developed national mail-order businesses. Edmund was, however, the only widely-known supplier of surplus optics.The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Edmund Scientific Corporation was a company based in Barrington, New Jersey that specialized in supplying surplus optics and other items via its mail order catalog and Factory Store. During four decades from the 1940s to the 1970s Edmund Scientific was virtually unique in its offerings to scientific hobbyists. Early historyIn 1942 amateur photographer Norman W. Edmund found it hard to find lenses he needed for his hobby. This led him to advertise lenses for sale in photography magazines. It was so successful he founded "'Edmund Salvage Corporation.'" It soon changed its name to Edmund Scientific and made its name with ads in publications like "Scientific American" as a supplier of chipped lenses, war-surplus optics, and low cost scientific gadgetry. Its advertisements caught the attention of hobbyists, amateur astronomers, high school students, and cash-strapped researchers. War surplusEdmund Scientific was part of the post-World War II "war surplus" phenomenon, when the U.S. government sold off large quantities of materials. "Army and Navy Stores" were a national phenomenon and originally sold military-surplus clothing. Surplus electronics found an outlet in dozens of shops, in New York City's "Radio Row" and elsewhere. A few issued catalogs and developed national mail-order businesses. Edmund was, however, the only widely-known supplier of surplus optics.The core of Edmund’s offerings was surplus lenses. These were single-element lenses, shipped in 2.5x4.25-inch (63x108 mm) coin envelopes, with the "approximate" diameter and focal length stenciled on them. Reflecting their salvage and surplus origins, available diameters and focal lengths did not fall into regular progressions. Edmund published crudely printed, stapled "books" describing experiments that could be performed with their lenses, and plans for building telescopes and other optical equipment. Edmund also sold lens "kits." The ten-lens kit cost less than $10 and included a booklet of plans for instruments that could supposedly be built with them.Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Unlike Heathkits, which were absolutely complete kits requiring only soldering and assembly, Edmund's "kits" consisted of only the lenses. A great deal of skill and effort would have been needed to fashion the telescopes, microscopes, or opaque projectors described. With single-element lenses, quality of the resulting optics was not high. Edmund even sold high-quality, thick, black cardboard tubes that many of the projects called for.Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Barrington, New Jersey — Infobox Settlement official name = Barrington, New Jersey settlement type = Borough nickname = motto = imagesize = image caption = image imagesize = image caption = image mapsize = 250x200px map caption = Barrington highlighted in Camden County.… …   Wikipedia

Buy 10" Inch 245mm 35.5mm Core Speaker Cone Paper Basin Woofer Drum Paper 2-Ring Cloth Edge Trumper Bass Repair Parts #1 at Aliexpress for .

Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a size ratio called optical magnification. When this number is less than one, it refers to a reduction in size, sometimes called de-magnification.

Fixed Focal Length Lenses, commonly referred to as C-Mount Lenses, are used in many robotics or inspection applications. Fixed Focal Length Lenses are imaging ...

Lens Technology (Shenzhen) Co., Ltd. Products:3D Lenticular Picture, 3D Plastic Box, 3D Customized Gifts, 3D Lenticular Printing, 3D Lenticular Sheet.

M A = tan ⁡ ε tan ⁡ ε 0 ≈ ε ε 0 {\displaystyle M_{A}={\frac {\tan \varepsilon }{\tan \varepsilon _{0}}}\approx {\frac {\varepsilon }{\varepsilon _{0}}}}

2021322 — OpenCV Template Matching ( cv2.matchTemplate ) · It's simple to implement, requiring only 2-3 lines of code · Template matching is ...

Basics of Image Processing and Computer Vision · Digital Image Presentation · Techniques for image preprocessing and image manipulation · Geometric image ...

*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

Note that both astronomical telescopes as well as simple microscopes produce an inverted image, thus the equation for the magnification of a telescope or microscope is often given with a minus sign.[citation needed]

External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

By convention, for magnifying glasses and optical microscopes, where the size of the object is a linear dimension and the apparent size is an angle, the magnification is the ratio between the apparent (angular) size as seen in the eyepiece and the angular size of the object when placed at the conventional closest distance of distinct vision: 25 cm from the eye.

Eyepiece — For the device for looking through a camera, see viewfinder. A collection of different types of eyepieces. 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… …   Wikipedia

Here, f {\textstyle f} is the focal length of the lens in centimeters. The constant 25 cm is an estimate of the "near point" distance of the eye—the closest distance at which the healthy naked eye can focus. In this case the angular magnification is independent from the distance kept between the eye and the magnifying glass.

Edmund's heyday, Edmund was able to capitalize on a growing national interest in science and astronomy. They expanded their business into a full line of telescopes and telescope kits as well as equipment, parts, and supplies for other scientific fields such as physics, optics, chemistry, electronics, and meteorology. They continued to grow as a supplier to teachers and schools with demonstration devices and kits that covered most fields of science. Edmund's catalog became a source for optical and mechanical parts useful in the field of amateur telescope making. A compilation of Edmunds' earlier pamphlets published as the book "All About Telescopes" offered many designs for telescopes of all sizes and configurations, which directed the builder to the relative Edmund catalog part numbers needed for each design. The "Factory Store" in Barrington, New Jersey also had a number of bins and shelves full of surplus and hard to find items which never made it into the catalogs.Edmunds catered to the 60's generation by expanding and highlighting their line of projectors, color wheels, black lights, filters, and other optical devices that could be used by rock bands and in psychedelic light shows. Other items that catered to the counterculture were eventually added to the catalog covering the fields of Biofeedback, ESP, Kirlian photography, Pyramid power, and alternative energy. In 1971, in the Whole Earth Catalog of items "relevant to independent education," Stewart Brand noted: "Edmund is the best source we know of for low-cost scientific gadgetry (including math and optics gear). [In this category,] many of the items we found independently... turned up in the Edmund catalog, so we were obliged to recommend that in this area we've been precluded." That is, the Edmund catalog was virtually a Whole Earth Catalog for items related to scientific fields.End of an eraIn the 1970s, as the viability of Edmund's business model waned, Norman Edmund's son Robert Edmund refashioned the business into two new ones, Edmund Scientifics and Edmund Optics. Edmund Scientifics marketed to consumers and specialized in science-themed toys, vaguely high-tech household gadgets, and "science gifts." Edmund Optics did not have a public showroom like Edmund Scientifics, although the two organizations shared the same building. The large back room of Edmund Scientifics still sold military surplus from WWII and other wars well into the 1980s and possibly the early 1990s. Some of the items in the surplus room were from German and other non-American militaries. None of these items were in the mail-order catalogs.In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)

In line with their focus on optics, Edmund Scientifics's entrance vestibule housed a pale-blue working WWII submarine periscope. Children were often drawn to this periscope. Drawing on the periscope's popularity, sometime in the 1970s a hall of mirrors, complete with black lights, was installed towards the rear of the building.As of 2007, Edmund Optics continues to offer brand-new stock optics, as well as offering custom and specialized optics to corporations and higher education institutions.Edmund Scientific todayIn 2000 Edmund Scientific was purchased by Science Kit and Boreal Laboratories, a western New York based science supply company. Science Kit and Boreal Laboratories is part of a group of companies that provide science supplies to elementary, middle, and high schools as well as colleges and universities. This group falls under the unofficial umbrella "VWR Education" and are owned by VWR International, a multi-national conglomerate with offices in India, China, Europe, Canada and the United States. They are no longer affliated with Edmund Optics Inc.As of 2007, online sales now make up the bulk of Edmund Scientific's revenues. The company still sells telescopes, microscopes, surplus optics, magnets and fresnel lenses, but the emphasis is on science-themed toys, novelty items, gifts, and gadgets. Edmund Scientific in movies *Wah Chang, the artist who designed and built several props in the 1960s for , used moiré patterns found in the Edmund Scientific Educator's and Designer's Moiré Kit for the texture used in the Starfleet communicator props.Fact|date=December 2007*Edmund Scientifics has provided items used in television shows such as House, MythBusters, 24, Modern Marvels, motion pictures such as Star Trek, and the new version of Escape to Witch Mountain.References*"The Last Whole Earth Catalog," (1971), ed. Stewart Brand et al.*Preface to "Edmund Scientific Catalog 751" Copyright 1974, Edmund Scientific Co.External links* [http://www.edmundoptics.com Edmund Optics] Website of the professional optics company* [http://www.scientificsonline.com Edmund Scientific] Website of the science supplies and gifts company* [http://www.anchoroptics.com Anchor Optics] Low-cost provider of optics and optical equipment (a division of Edmund Optics)