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  2. International Fujita scale - Wikipedia

    en.wikipedia.org/wiki/International_Fujita_scale

    The International Fujita scale (abbreviated as IF-Scale) is a scale that rates the intensity of tornadoes and other wind events based on the severity of the damage they cause. [1] It is used by the European Severe Storms Laboratory (ESSL) and various other organizations including Deutscher Wetterdienst (DWD) and State Meteorological Agency ...

  3. Enhanced Fujita scale - Wikipedia

    en.wikipedia.org/wiki/Enhanced_Fujita_scale

    The Enhanced Fujita scale (abbreviated as EF-Scale) is a scale that rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States and France. [1] The EF scale is also unofficially used in other countries, including China and Brazil.

  4. Tycho-2 Catalogue - Wikipedia

    en.wikipedia.org/wiki/Tycho-2_Catalogue

    To enable rapid access of specific stars in the catalogue, WCSTools software numbers each star using its Guide Star region number (0001 to 9537) and a five-digit star number within each region, separated by a decimal point. sty2 lists Tycho-2 stars by number or sky region. imty2 lists the Tycho-2 stars within an IRAF or FITS image using the world coordinate system defined in its header.

  5. European Southern Observatory - Wikipedia

    en.wikipedia.org/wiki/European_Southern_Observatory

    The European Organisation for Astronomical Research in the Southern Hemisphere, [2] commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based astronomy. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and ...

  6. Digitized Sky Survey - Wikipedia

    en.wikipedia.org/wiki/Digitized_Sky_Survey

    The term Digitized Sky Survey originally referred to the publication in 1994 of a digital version of an all-sky photographic atlas used to produce the first version of the Guide Star Catalog. [1] [2] For the northern sky, the National Geographic Society – Palomar Observatory Sky Survey E-band (red, named after the Eastman Kodak IIIa-E ...

  7. Tornado intensity - Wikipedia

    en.wikipedia.org/wiki/Tornado_intensity

    EF3 (T6–T7) damage is a serious risk to life and limb and the point at which a tornado statistically becomes significantly more destructive and deadly. Few parts of affected buildings are left standing; well-built structures lose all outer and some inner walls. Unanchored homes are swept away, and homes with poor anchoring may collapse entirely.

  8. Extremely large telescope - Wikipedia

    en.wikipedia.org/wiki/Extremely_large_telescope

    Comparison of nominal sizes of apertures of the above extremely large telescopes and some notable optical telescopes. An extremely large telescope (ELT) is an astronomical observatory featuring an optical telescope with an aperture for its primary mirror from 20 metres up to 100 metres across, [1] [2] when discussing reflecting telescopes of optical wavelengths including ultraviolet (UV ...

  9. Very Large Telescope - Wikipedia

    en.wikipedia.org/wiki/Very_Large_Telescope

    Because of the many mirrors involved in the optical train, about 95% of the light is lost before reaching the instruments at a wavelength of 1 μm, 90% at 2 μm and 75% at 10 μm. [63] This refers to reflection off 32 surfaces including the Coudé train, the star separator, the main delay line, beam compressor and feeding optics. Additionally ...