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Monday, August 17, 2020 | History

2 edition of Computation of achromatic objectives. found in the catalog.

Computation of achromatic objectives.

Robert Eugene Stephens

Computation of achromatic objectives.

by Robert Eugene Stephens

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  • 8 Currently reading

Published by U.S. Govt. Print. Off.] in [Washington .
Written in English

    Subjects:
  • Achromatism.

  • Classifications
    LC ClassificationsQC100 .U555 no. 549
    The Physical Object
    Paginationii, 7 p.
    ID Numbers
    Open LibraryOL6170154M
    LC Control Number54060793
    OCLC/WorldCa5282405

    Abstract. The overall aim in producing this book is to extend recent writing on African cities, 1 with a focus on physical urban development issues, and in so doing, to critique key concepts used in contemporary analysis (and subsequent policy and practice). As noted in the acknowledgments, the book draws from four decades of a wide range of urban experience as well as specific recent. The concept of ‘management by objectives' became popular in the United States in the s when highly respected business expert Peter Drucker () wrote his influential book The Practice of Management (). The definition of management by objectives (MBO) is "a technique in which all levels of management are encouraged to specify and agree quantitative and/or qualitative objectives.

    Achromatic Lenses are ideal for a range of applications, including fluorescence microscopy, image relay, inspection, or spectroscopy. An Achromatic Lens, which is often designed by either cementing two elements together or mounting the two elements in a housing, creates smaller spot sizes than comparable singlet lenses. Advances in extreme-ultraviolet (EUV) and X-ray optics are providing powerful new capabilities in high-resolution imaging and trace-element analysis of microscopic specimens1, and the potential.

    An achromatic color scheme can have a calming effect for those who live in them. Much like in other rooms, white and gray can make a room seem bigger. Black furniture, like bed frames and chests. Expectedly, the difference diminishes with the magnitude of aberration. Very approximately, the ratio of encircled energy for secondary spectrum vs. spherical aberration changes in proportion to (F+7)/(F+6), F being, as before, the focal ratio. The distribution profile is not the same, however, with the long focus achromats apparently having more encircled energy not only within the first dark.


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Computation of achromatic objectives by Robert Eugene Stephens Download PDF EPUB FB2

An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical atic lenses are corrected to bring two wavelengths (typically red and blue) into focus on the same plane.

The most common type of achromat is the achromatic doublet, which is composed of two individual lenses made from glasses with different amounts of dispersion.

Additional Physical Format: Online version: Stephens, Robert E. Computation of achromatic objectives. Washington ; For sale by the Supt. of Docs., U.S. Govt. Print. Computation of Achromatic Objectives.

Robert E. Stephens. Procedures for the computation of the curves for achromatic doublet objectives by the algebraic method are presented in considerable detail, using the design of two such objectives as examples. The reasons for choosing particular pairs of glass types and the changes in.

The standard TF setup is depicted in Fig. 8 and consists of a grating which is imaged onto the sample via a 2f–2f telescope consisting of an achromatic lens and the microscope objective.

Since this is a perfect imaging system, the pattern illuminating the grating is simply demagnified and relayed onto the objective. Opteka Achromatic 10x Diopter Close-Up Macro Lens for Sony E-Mount a7r, a7s, a7, a, a, a, a, a, NEX-7, 6, 5T, 5N, 5R Digital Cameras (Fits mm, 49mm and 58mm Threaded Lenses) out of 5 stars An achromatic objective corrects for color and has a flat field across the central 65% of the image.

It’s usually a pair of lenses. Semi-plan (semi-planar, sometimes called micro-plan) objectives have an 80% flat field.

They can either be two lens element achromats or three or more element apochromats. However, the design of an achromatic doublet lens lends itself to the sort of calculation we are doing in this chapter.

A combination of two lenses in contact, a converging lens made of crown glass and a weaker diverging lens made of flint glass, can be designed so that the combination is a converging lens that is almost achromatic.

Achromatic objectives are also corrected for spherical aberration in the color green ( nanometers; see Table 1).

Achromatic objectives' limited correction can result in images with a magenta halo if focus is chosen in the green region of the spectrum. The lack of correction for flatness of field (or field curvature) presents a further problem. Flint-forward achromatic doublets Possible versions of the flint-forward doublets are shown on Figures 2 and 3.

The formulas for calculation of the radii for the each version are collected in Table I.1, in Appendix I. The versions with only a numeric label are the initial variants. The achromatic doublet corrects chromatic aberrations, but the corrections can be calculated with thin lenses.

Colour-corrective achromatic doublets for objectives, most notably the objective lens for a telescope are most common and easiest to explain.

The objective form is also used elsewhere, even if it is not a telescope. This objective is better suited for color viewing or recording than achromatic objectives. Apochromatic objective–This is the most expensive objective.

It is chromatically adjusted for four colors (deep blue, blue, green and red) and spherically corrected for deep blue, blue and sometimes green. This is the best choice for color viewing. Microscope objectives are corrected for field curvature and color aberration.

The difference between an Achromat and a Plan Achromat microscope objective lens is the degree of the flatness of field. Because an achromat microscope objective does not have a correction for the curvature of the lens, the very outer edges of the circular image you. Custom Achromatic Lenses From S.O.

Achromatic lenses have many applications. Customers with specialized needs may need to order custom achromatic lenses to get the results they require. At Shanghai Optics, we design and manufacture high-quality precision achromatic. Computation of the Seidel Aberrations 12 Lenses in Which Stop Position Is a Degree of Freedom The H' - L Plot Simple Landscape Lenses A Periscopic Lens Achromatic Landscape Lenses Achromatic Double Lenses 13 Symmetrical Double Anastigmats with Fixed Stop The Designs of a Dagor Lens Achromatic Telescope Objectives (Thin Lens Theory) Achromatic Telescope Objectives (Design Forms) The Diffractive Surface in Lens Design The Cooke Triplet Anastigmat A Generalized (Nonautomatic, Old-Fashioned) Design Technique viii Contents.

The front lens was a cemented doublet, the rear component an air-spaced doublet. This was probably the first lens ever to be designed by computation, in this case by logarithmic tables.

The limitation of the doublet objective is that astigmatism cannot be corrected in a single component, and this severely limits the field angle that it can cover.

This was a simple plano-convex or bi-convex lens, or sometimes a combination of lenses. With the development of the modern achromatic objective inby Joseph Jackson Lister, the need for better condensers became increasingly apparent. Bythe use of the achromatic condenser was introduced in France, by Felix Dujardin, and Chevalier.

The objective of this paper is to compare some of the well-known texture-based approaches: autocorrelation function, GLCM, and Gabor filters, used in a segmentation of digitized historical. A 50×, NA objective with the theoretical resolution of nm was used to magnify the sample.

The illumination light in the experiments was a white light source and filtered by a /30 nm bandpass filter (FF01–/30–25, Semrock). The focal length of the two achromatic lenses was. The Edmund Optics® Autocollimator is comprised of an achromatic objective, a light source, reticle, beamsplitter and an eyepiece with a reticle calibrated in small angle increments.

The reticle pattern, a cross-hair, is projected onto a reflective surface. The returning reflected beam is diverted, via the beamsplitter, to the calibrated eyepiece.

Color Terminology GlossaryIntroduction to the color terminology glossary filled with definitions to a wide range of words related to matic: free of color, without color, colorless. Achromatic is used to describe the absence of any hue. Examples of achromatic schemes -- black and white, black and gray, gray and white.APOCHROMAT OBJECTIVES: Apochromat objective lenses are made up of several fluorite lenses in combination with glass lenses, achieving correction for chromatic aberrations at three wavelengths in the red, green and blue, and for spherical aberration throughout the visible spectrum to a greater extent than with achromat lenses.

Figure 2: X-ray optical constants and their consequences for EUV and soft X-ray achromatic Fresnel objectives. At top (a, b) are shown the oscillator strengths .