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  2. Parallax - Wikipedia

    en.wikipedia.org/wiki/Parallax

    Parallax also affects optical instruments such as rifle scopes, binoculars, microscopes, and twin-lens reflex cameras that view objects from slightly different angles. Many animals, along with humans, have two eyes with overlapping visual fields that use parallax to gain depth perception ; this process is known as stereopsis .

  3. Exit pupil - Wikipedia

    en.wikipedia.org/wiki/Exit_pupil

    In optics, the exit pupil is a virtual aperture in an optical system. Only rays which pass through this virtual aperture can exit the system. The exit pupil is the image of the aperture stop in the optics that follow it. In a telescope or compound microscope, this image is the image of the objective element (s) as produced by the eyepiece.

  4. Field of view - Wikipedia

    en.wikipedia.org/wiki/Field_of_view

    Angular field of view is typically specified in degrees, while linear field of view is a ratio of lengths. For example, binoculars with a 5.8 degree (angular) field of view might be advertised as having a (linear) field of view of 102 mm per meter. As long as the FOV is less than about 10 degrees or so, the following approximation formulas ...

  5. Eye relief - Wikipedia

    en.wikipedia.org/wiki/Eye_relief

    Eye relief. The eye relief of an optical instrument (such as a telescope, a microscope, or binoculars) is the distance from the last surface of an eyepiece within which the user's eye can obtain the full viewing angle. If a viewer's eye is outside this distance, a reduced field of view will be obtained. The calculation of eye relief is complex ...

  6. Minute and second of arc - Wikipedia

    en.wikipedia.org/wiki/Minute_and_second_of_arc

    A minute of arc is π 10 800 of a radian . A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol ″, [2] is 1 60 of an arcminute, 1 3600 of a degree, [1] 1 1 296 000 of a turn, and π 648 000 (about 1 206 264.8) of a radian. These units originated in Babylonian astronomy as sexagesimal (base 60) subdivisions of the degree ...

  7. Finderscope - Wikipedia

    en.wikipedia.org/wiki/Finderscope

    A finderscope is an accessory sighting device used in astronomy and stargazing, typically a small auxiliary refracting telescope / monocular mounted parallelly on a larger astronomical telescope along the same line of sight. The finderscope usually has a much smaller magnification than the main telescope, thus providing a larger field of view ...

  8. List of telescope parts and construction - Wikipedia

    en.wikipedia.org/wiki/List_of_telescope_parts...

    Optics. Mirrors and lenses are the critical light-bending components of a telescope. Objective: The first lens or curved mirror that collects and focuses the incoming light. Primary lens: The objective of a refracting telescope. Primary mirror: The objective of a reflecting telescope. Corrector plate: A full aperture negative lens placed before ...

  9. Schmidt–Cassegrain telescope - Wikipedia

    en.wikipedia.org/wiki/Schmidt–Cassegrain_telescope

    The telescope is noted for its large field of view, up 60 times a full moon. Derivative designs. While there are many variations of the Schmidt–Cassegrain telescope design (both mirrors spherical, both mirrors aspherical, or one of each), they can be divided into two principal types: compact and non-compact. In the compact form, the corrector ...