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  2. Reflecting telescope - Wikipedia

    en.wikipedia.org/wiki/Reflecting_telescope

    A convex secondary mirror is placed just to the side of the light entering the telescope, and positioned afocally so as to send parallel light on to the tertiary. The concave tertiary mirror is positioned exactly twice as far to the side of the entering beam as was the convex secondary, and its own radius of curvature distant from the secondary.

  3. Secondary mirror - Wikipedia

    en.wikipedia.org/wiki/Secondary_mirror

    The secondary mirror assembly of the Keck Telescope and its relationship to the primary mirror. A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary.

  4. Reflecting instrument - Wikipedia

    en.wikipedia.org/wiki/Reflecting_instrument

    The telescope (AB in the adjacent image), has an eyepiece at one end and a mirror (D) partway along its length with one objective lens at the far end (B). The mirror only obstructs half the field (either left or right) and permits the objective to be seen on the other. Reflected in the mirror is the image from the second objective lens (C).

  5. Catadioptric system - Wikipedia

    en.wikipedia.org/wiki/Catadioptric_system

    A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses and curved mirrors . Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses.

  6. Newtonian telescope - Wikipedia

    en.wikipedia.org/wiki/Newtonian_telescope

    Newtonian telescope design. A Newtonian telescope is composed of a primary mirror or objective, usually parabolic in shape, and a smaller flat secondary mirror.The primary mirror makes it possible to collect light from the pointed region of the sky, while the secondary mirror redirects the light out of the optical axis at a right angle so it can be viewed with an eyepiece.

  7. Lieberkühn reflector - Wikipedia

    en.wikipedia.org/wiki/Lieberkühn_reflector

    A Lieberkühn mirror from Emil Busch AG (now Rathenower Optische Werke) circa 1930, digital collection of the Deutsches Museum. [1]A Lieberkühn reflector [2] (also known as Lieberkühn mirror [3] or simply Lieberkühn [2] [4]) is an illumination device for incident light illumination (epi-illumination) in light microscopes.

  8. Optical telescope - Wikipedia

    en.wikipedia.org/wiki/Optical_telescope

    The telescope is more a discovery of optical craftsmen than an invention of a scientist. [1] [2] The lens and the properties of refracting and reflecting light had been known since antiquity, and theory on how they worked was developed by ancient Greek philosophers, preserved and expanded on in the medieval Islamic world, and had reached a significantly advanced state by the time of the ...

  9. Liquid-mirror telescope - Wikipedia

    en.wikipedia.org/wiki/Liquid-mirror_telescope

    Since the mirror is liquid, it responds to this torque by changing its aim direction. The point in the sky at which the mirror is aimed is not exactly overhead, but is displaced slightly to the north or south. The amount of the displacement depends on the latitude, the rotation speeds, and the parameters of the telescope's design.