A report on Light and Telescope

A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.

The 100-inch (2.54 m) Hooker reflecting telescope at Mount Wilson Observatory near Los Angeles, USA, used by Edwin Hubble to measure galaxy redshifts and discover the general expansion of the universe.

The electromagnetic spectrum, with the visible portion highlighted

The 60-inch Hale (debuted in 1908) considered to be the first modern large research reflecting telescope.

Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily

The primary mirror assembly of James Webb Space Telescope under construction. This is a segmented mirror and its coated with Gold to reflect (orange-red) visible light, through near-infrared to the mid-infrared

$Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.$

Modern telescopes typically use CCDs instead of film for recording images. This is the sensor array in the Kepler spacecraft.

Hong Kong illuminated by colourful artificial lighting.

A 1.2-meter (47 in) reflecting telescope

The Very Large Array at Socorro, New Mexico, United States.

$Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.$

Einstein Observatory was a space-based focusing optical X-ray telescope from 1978.

The Compton Gamma Ray Observatory is released into orbit by the Space Shutte in 1991, and it would operate until the year 2000

The reflectors of HEGRA detect flashes of light in the atmosphere, thus detecting high energy particles

A diagram of the electromagnetic spectrum with the Earth's atmospheric transmittance (or opacity) and the types of telescopes used to image parts of the spectrum.

Six views of the Crab nebula supernova remnant, viewed at different wavelengths of light by various telescopes

The Five-hundred-meter Aperture Spherical radio Telescope in Guizhou, China, is the world's largest filled-aperture radio telescope

Using a telescope, Rømer observed the motions of Jupiter and one of its moons, Io.

- Light

Optical telescopes, using visible light

- Telescope

3 related topics with Alpha

Electromagnetic spectrum

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Range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.

A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths

Plot of Earth's atmospheric opacity to various wavelengths of electromagnetic radiation. This is the surface-to-space opacity, the atmosphere is transparent to longwave radio transmissions within the troposphere but opaque to space due to the ionosphere.

Plot of atmospheric opacity for terrestrial to terrestrial transmission showing the molecules responsible for some of the resonances

The amount of penetration of UV relative to altitude in Earth's ozone

This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end.

Light was intensively studied from the beginning of the 17th century leading to the invention of important instruments like the telescope and microscope.

Wavelength

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Spatial period of a periodic wave—the distance over which the wave's shape repeats.

Sinusoidal standing waves in a box that constrains the end points to be nodes will have an integer number of half wavelengths fitting in the box.

A standing wave (black) depicted as the sum of two propagating waves traveling in opposite directions (red and blue)

Wavelength is decreased in a medium with slower propagation.

$Refraction: upon entering a medium where its speed is lower, the wave changes direction.$

Separation of colors by a prism (click for animation)

Various local wavelengths on a crest-to-crest basis in an ocean wave approaching shore

A sinusoidal wave travelling in a nonuniform medium, with loss

A wave on a line of atoms can be interpreted according to a variety of wavelengths.

Wavelength of a periodic but non-sinusoidal waveform.

Pattern of light intensity on a screen for light passing through two slits. The labels on the right refer to the difference of the path lengths from the two slits, which are idealized here as point sources.

$Diffraction pattern of a double slit has a single-slit envelope.$

Relationship between wavelength, angular wavelength, and other wave properties.

Examples of waves are sound waves, light, water waves and periodic electrical signals in a conductor.

Diffraction is the fundamental limitation on the resolving power of optical instruments, such as telescopes (including radiotelescopes) and microscopes.

$A 200 mm refracting telescope at the Poznań Observatory$

Refracting telescope

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$A 200 mm refracting telescope at the Poznań Observatory$

Optical diagram of Galilean telescope
y – Distant object; y′ – Real image from objective; y″ – Magnified virtual image from eyepiece;
D – Entrance pupil diameter; d – Virtual exit pupil diameter; L1 – Objective lens; L2 – Eyepiece lens e – Virtual exit pupil – Telescope equals

$Engraved illustration of a 150 ft focal length Keplerian astronomical refracting telescope built by Johannes Hevelius.$

Alvan Clark polishes the big Yerkes achromatic objective lens, over 1 meter across, in 1896.

$This 12 inch refractor is mounted in dome and a mount the rotates with the turn of the Earth$

$The Greenwich 28-inch refractor is a popular tourist attraction in 21st century London$

The Apochromatic lens usually comprises three elements that bring light of three different frequencies to a common focus

$The 102 cm refractor, at Yerkes Observatory, the largest achromatic refractor ever put into astronomical use (photo taken on 6 May 1921, as Einstein was visiting)$

The "Große Refraktor" a double telescope with a 80cm (31.5") and 50 cm (19.5") lenses, was used to discover calcium as an interstellar medium in 1904.

Astronaut trains with camera with large lens

Touristic telescope pointed to Matterhorn in Switzerland

$The Yerkes Great refractor mounted at the 1893 World's Fair in Chicago; the tallest, longest, and biggest aperture refactor up to that time.$

$The 68 cm refractor at the Vienna University Observatory$

A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope).

The objective in a refracting telescope refracts or bends light.