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As an example, a telescope having an f /6 objective and imaging at 0.55 micrometers has a spatial cutoff frequency of 303 cycles/millimeter. High-resolution black-and-white film is capable of resolving details on the film as small as 3 micrometers or smaller, thus its cutoff frequency is about 150 cycles/millimeter.
Comparison of nominal sizes of apertures of the Overwhelmingly Large Telescope and some notable optical telescopes. The Overwhelmingly Large Telescope (OWL) was a conceptual design by the European Southern Observatory (ESO) organisation for an extremely large telescope, which was intended to have a single aperture of 100 metres in diameter.
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 ...
Sparrow's resolution limit is nearly equivalent to the theoretical diffraction limit of resolution, the wavelength of light divided by the aperture diameter, and about 20% smaller than the Rayleigh limit. For example, in a 200 mm (eight-inch) telescope, Rayleigh's resolution limit is 0.69 arc seconds, Sparrow's resolution limit is 0.54 arc seconds.
In order to perform aperture synthesis imaging, a large number of telescopes are required laid out in a 2-dimensional arrangement with a dimensional precision better than a fraction (0.25x) of the required image resolution. The angular resolution R of an interferometer array can usually be approximated by =
The Houghton telescope or Lurie–Houghton telescope is a design that uses a wide compound positive-negative lens over the entire front aperture to correct spherical aberration of the main mirror. If desired, the two corrector elements can be made with the same type of glass, since the Houghton corrector's chromatic aberration is minimal.
Dawes' limit is a formula to express the maximum resolving power of a microscope or telescope. [1] It is so named after its discoverer, William Rutter Dawes, [2] although it is also credited to Lord Rayleigh. The formula takes different forms depending on the units.
This is a list of large optical telescopes. For telescopes larger than 3 meters in aperture see List of largest optical reflecting telescopes. This list combines large or expensive reflecting telescopes from any era, as what constitutes famous reflector has changed over time.