wavefront modifier Comparison Table

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wavefront modifier comparison table

Subject has dispersion has focal ratio has reflective coat has definition has wavefront modification has focal length has index of refraction

aspheric An optical surface with departures in shape from a perfect sphere in order to cancel optical imperfections or aberrations. shape

atmospheric dispersion corrector An optical device usually comprising two thin prisms which can rotate to compensate for the elongation of a star image caused by the wavelength dependence of the refractive index of air. wavelength

focal reducer An optical component or system for changing the image scale of a telescope to achieve a better match between the seeing disk and the pixel size. See optical matching. shape

lens shape

mirror shape

Nicol prism A device made from a split crystal of Iceland spar with which plane-polarized light can be detected. polarization

objective The primary mirror of a reflecting telescope (or the primary lens of a refractor). shape

optical fibre Glass and transparent plastics can be made into a very thin wire or fiber. Typical dimensions are 10-50 µm. If a ray enters one end of a fiber at the appropriate angle, it will undergo total internal reflection and travel down the fiber without much loss through the sides. shape

optical matching The use of lenses or other optical devices to match the size of the image of the seeing disk, as it appears in the focal plane of the telescope, to the physical size of the CCD pixels. If the telescope yields 10 arcseconds per millimeter and the seeing is 1 arcsecond then the image is 0.1 mm in size. But a typical CCD pixel is 0.022 mm, five times smaller. shape

Pockels cell An electro-optic crystal used as a reversible waveplate by applying alternately high positive and negative voltage. polarization

spectrograph dispersing element The part of a spectrograph which disperses the light into component colors wavelength

Next optical device: coating Up: optical device Previous optical device: focus

Subject	has dispersion	has focal ratio	has reflective coat	has definition	has wavefront modification	has focal length	has index of refraction
aspheric				An optical surface with departures in shape from a perfect sphere in order to cancel optical imperfections or aberrations.	shape
atmospheric dispersion corrector				An optical device usually comprising two thin prisms which can rotate to compensate for the elongation of a star image caused by the wavelength dependence of the refractive index of air.	wavelength
focal reducer				An optical component or system for changing the image scale of a telescope to achieve a better match between the seeing disk and the pixel size. See optical matching.	shape
lens					shape
mirror					shape
Nicol prism				A device made from a split crystal of Iceland spar with which plane-polarized light can be detected.	polarization
objective				The primary mirror of a reflecting telescope (or the primary lens of a refractor).	shape
optical fibre				Glass and transparent plastics can be made into a very thin wire or fiber. Typical dimensions are 10-50 µm. If a ray enters one end of a fiber at the appropriate angle, it will undergo total internal reflection and travel down the fiber without much loss through the sides.	shape
optical matching				The use of lenses or other optical devices to match the size of the image of the seeing disk, as it appears in the focal plane of the telescope, to the physical size of the CCD pixels. If the telescope yields 10 arcseconds per millimeter and the seeing is 1 arcsecond then the image is 0.1 mm in size. But a typical CCD pixel is 0.022 mm, five times smaller.	shape
Pockels cell				An electro-optic crystal used as a reversible waveplate by applying alternately high positive and negative voltage.	polarization
spectrograph dispersing element				The part of a spectrograph which disperses the light into component colors	wavelength