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  2. Foucault knife-edge test - Wikipedia

    en.wikipedia.org/wiki/Foucault_knife-edge_test

    Some telescope makers use a variant of the Foucault test called a Ronchi test that replaces the knife edge with a grating (similar to a very coarse diffraction grating) comprising fine parallel wires, an etching on a glass plate, a photograph negative or computer printed transparency. Ronchi test patterns are matched to those of standard ...

  3. Ritchey–Chrétien telescope - Wikipedia

    en.wikipedia.org/wiki/Ritchey–Chrétien_telescope

    The RCT has a wider field of view free of optical errors compared to a more traditional reflecting telescope configuration. Since the mid 20th century, a majority of large professional research telescopes have been Ritchey–Chrétien configurations; some well-known examples are the Hubble Space Telescope , the Keck telescopes and the ESO Very ...

  4. List of telescope parts and construction - Wikipedia

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

    Telecompressor or focal reducer: Optical element to decrease the telescope's focal length and magnification (usually by a fixed percentage) and widen the field of view, providing opposite effects of a Barlow lens. Star Diagonal: Used to change the angle of the light coming out of a telescope, for easier viewing.

  5. Wolter telescope - Wikipedia

    en.wikipedia.org/wiki/Wolter_telescope

    Wolter's key innovation was that by using two mirrors it is possible to create a telescope with a usably wide field of view. In contrast, a grazing incidence telescope with just one parabolic mirror could focus X-rays, but only very close to the centre of the field of view. The rest of the image would suffer from extreme coma.

  6. Fine Guidance Sensor (HST) - Wikipedia

    en.wikipedia.org/wiki/Fine_Guidance_Sensor_(HST)

    From the center to outer edge of the FGS field of view is 14.1 arcminutes [1] This is a diagram of the field of view of each Hubble Space Telescope instrument, including the three FGS instruments (FGS field of view(s) highlighted in yellow) A Fine Guidance Sensor being refurbished between servicing missions SM3A and SM4 A fine guidance sensors in space on STS Servicing Mission 2 in 1997

  7. Nasmyth telescope - Wikipedia

    en.wikipedia.org/wiki/Nasmyth_telescope

    The twin 10-meter telescopes at W. M. Keck Observatory in Hawaii, the 8.2-meter Subaru Telescope sited next to them, the four 8.2-meter Unit Telescopes of ESO's Very Large Telescope and their predecessor the 3.6-meter New Technology Telescope are notable examples that support an array of specialized instruments on their Nasmyth platforms, with a similar design being used for the future Thirty ...

  8. Groundbreaking telescope reveals first piece of new cosmic map

    www.aol.com/groundbreaking-telescope-reveals...

    Zooming in on a portion of the Euclid telescope's map 600 times reveals the galaxies within the cluster Abell 3381, located 470 million light-years away from Earth. ... view the cosmos. A prime ...

  9. Catadioptric system - Wikipedia

    en.wikipedia.org/wiki/Catadioptric_system

    Examples of sub-aperture corrector catadioptric telescopes include the Argunov–Cassegrain telescope, the Klevtsov–Cassegrain telescope and sub-aperture corrector Maksutovs, which use as a "secondary mirror" an optical group consisting of lens elements and sometimes mirrors designed to correct aberration, as well as Jones-Bird Newtonian ...