Schmidt–Cassegrainn.

Brit.

/ˌʃmɪtˈkasɪˌɡreɪn/, U.S.

/ˌʃmɪtˈkæsɪˌɡreɪn/

Origin: From proper names. Etymons: proper names Schmidt, Cassegrain.

Etymology: < the names of Bernhard Voldemar Schmidt (see Schmidt n.) and Laurent Cassegrain (see Cassegrainian adj.).

Astronomy.

I. Simple uses.

1. An astronomical telescope or camera employing a concave primary mirror, a convex secondary mirror, and a Schmidt corrector plate, so as to eliminate spherical aberrations and achieve a long focal length within a relatively compact housing (see also sense 2).

ΘΚΠ

the world > the universe > cosmology > science of observation > astronomical instruments > observational instruments > [noun] > telescope

sector1711

astronomical telescope1723

sweeper1786

comet seeker1819

photo-telescope1893

Schmidt–Cassegrain1943

space telescope1953

photopolarimeter1971

1943 Proc. Physical Soc. 55 436 Next come what might be termed monocentric Schmidt-Cassegrains, with three coincident plates of zero total length.

2004 M. Mobberley New Amateur Astronomer ii. 22 One thing Schmidt–Cassegrains can't deliver is a wide field of view.

II. Compounds

2. attributive. Designating an astronomical telescope or camera employing a concave primary mirror, a convex secondary mirror, and a Schmidt corrector plate, so as to eliminate spherical aberrations and achieve a long focal length within a relatively compact housing (as Schmidt–Cassegrain telescope, Schmidt–Cassegrain camera, etc.). Also: of or characteristic of such a telescope or camera.Schmidt–Cassegrain telescopes combine the characteristics of Schmidt cameras and Cassegrain telescopes. They are typically constructed so that light passes through the Schmidt corrector plate and is then reflected by the primary mirror to the secondary, which produces an image at a focal point in front of or behind the primary mirror.In most Schmidt–Cassegrain telescopes the focal point is behind the primary mirror, which has a central hole to allow light from the secondary mirror to pass.

ΚΠ

1944 Monthly Notices Royal Astron. Soc. 104 51 In the present paper we use it [sc. the plate-diagram method] to make a general survey of the Schmidt–Cassegrain systems.

1950 Nature 6 May 703/2 (caption) The Schmidt–Cassegrain telescope mounted in the Mills Observatory, Dundee.

1970 Notes from Observatories 90 252 The diffracted beam is received by a semi-solid quartz Schmidt–Cassegrain camera.

2003 Jrnl. Geophysical Res. 108 2/2 The Mie receiver uses a 35cm telescope of Schmidt-Cassegrain configuration.

2015 J. Ashley Astrophotography on the Go iv. 75 Schmidt Cassegrain telescopes typically have a focal ratio of f/10.

This entry has been updated (OED Third Edition, June 2019; most recently modified version published online March 2022).

单词	schmidt–cassegrain
释义	Schmidt–Cassegrainn. Brit. /ˌʃmɪtˈkasɪˌɡreɪn/, U.S. /ˌʃmɪtˈkæsɪˌɡreɪn/ Origin: From proper names. Etymons: proper names Schmidt, Cassegrain. Etymology: < the names of Bernhard Voldemar Schmidt (see Schmidt n.) and Laurent Cassegrain (see Cassegrainian adj.). Astronomy. I. Simple uses. 1. An astronomical telescope or camera employing a concave primary mirror, a convex secondary mirror, and a Schmidt corrector plate, so as to eliminate spherical aberrations and achieve a long focal length within a relatively compact housing (see also sense 2). ΘΚΠ the world > the universe > cosmology > science of observation > astronomical instruments > observational instruments > [noun] > telescope sector1711 astronomical telescope1723 sweeper1786 comet seeker1819 photo-telescope1893 Schmidt–Cassegrain1943 space telescope1953 photopolarimeter1971 1943 Proc. Physical Soc. 55 436 Next come what might be termed monocentric Schmidt-Cassegrains, with three coincident plates of zero total length. 2004 M. Mobberley New Amateur Astronomer ii. 22 One thing Schmidt–Cassegrains can't deliver is a wide field of view. II. Compounds 2. attributive. Designating an astronomical telescope or camera employing a concave primary mirror, a convex secondary mirror, and a Schmidt corrector plate, so as to eliminate spherical aberrations and achieve a long focal length within a relatively compact housing (as Schmidt–Cassegrain telescope, Schmidt–Cassegrain camera, etc.). Also: of or characteristic of such a telescope or camera.Schmidt–Cassegrain telescopes combine the characteristics of Schmidt cameras and Cassegrain telescopes. They are typically constructed so that light passes through the Schmidt corrector plate and is then reflected by the primary mirror to the secondary, which produces an image at a focal point in front of or behind the primary mirror.In most Schmidt–Cassegrain telescopes the focal point is behind the primary mirror, which has a central hole to allow light from the secondary mirror to pass. ΚΠ 1944 Monthly Notices Royal Astron. Soc. 104 51 In the present paper we use it [sc. the plate-diagram method] to make a general survey of the Schmidt–Cassegrain systems. 1950 Nature 6 May 703/2 (caption) The Schmidt–Cassegrain telescope mounted in the Mills Observatory, Dundee. 1970 Notes from Observatories 90 252 The diffracted beam is received by a semi-solid quartz Schmidt–Cassegrain camera. 2003 Jrnl. Geophysical Res. 108 2/2 The Mie receiver uses a 35cm telescope of Schmidt-Cassegrain configuration. 2015 J. Ashley Astrophotography on the Go iv. 75 Schmidt Cassegrain telescopes typically have a focal ratio of f/10. This entry has been updated (OED Third Edition, June 2019; most recently modified version published online March 2022). < n.1943
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