User manual MINOX ED-GLAS BROCHURE

[. . . ] I N N O VAT I O N S IN BINOCULAR ENGINEERING (II) W H A T 'S THE BENEFIT OF ED-GLASS IN A TELESCOPE lars, therefore features at least 2 lenses of different glass types. By designing the correct radius of the lens elements and selecting the right types of glass materials, the optics engineer can position at least two of the colored partial images at the same place and match their size. The remaining residual aberration for the other colors is usually so slight that the image already appears free from chromatic error. [. . . ] The use of special glass containing fluoride in the new MINOX binoculars with high magnification and MINOX spotting scopes, has successfully passed on this proven technology ? The experience gathered over decades in the production of top quality optical systems has brought forth MINOX products with a performance reaching the limits of technical feasibility. The profound knowledge in the production of top-class lenses led to stringent quality standards which apply to MINOX binoculars and telescopes as well. Continuous innovation at MINOX means a clear advantage for the observer in image sharpness and brightness. With ED glass (also called FL for fluoride glass and APO for apochromatically corrected) MINOX is setting new standards in nature observation. What are the advantages of ED glass in telescopes?White light is split into its component colors when it passes through a prism or a lens. The reason for this, as with other transparent materials, is the change in the refractive index for the different colors, known as the dispersion of the glass in question. The amount of dispersion in the different types of optical glass depends on the glass composition, i. e. dispersion is a material constant of the glass used. This color dispersion of incident light means that the image of an object imaged by a simple lens is split into many colored partial images which are not only positioned at different locations behind the lens, but also differ in size. If you pick up such an image on a screen or look at it with a magnifying glass, which is what the eyepiece represents, instead of sharp details and contours you will see, depending on the focusing, a more or less sharp core in one color, e. g. blue-green, which is surrounded by a more or less blurred corona in a different color, e. g. Altogether the image is unsharp due to this chromatic aberration which, in principle, cannot be eliminated by a single lens. As the specific dispersion of the various types of optical glass materials are ­ fortunately ­ different, by combining at least 2 lenses of different glass types it is possible to correct their chromatic aberration. [. . . ] This glass provides a plastic image exceptionally rich in detail and with high color rendition throughout the visual field. The observer is able to see a true-to-life image, even under critical light conditions. MINOX GmbH · Walter-Zapp-Str. 4 · D - 35578 Wetzlar · Tel. : +49 (0) 6441 / 917-0 · Fax: +49 (0) 6441 / 917-612 · www. minox. com Minox information order number: 99 199 [. . . ]