Stellar Interferometer

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stellar interferometer

[′stel·ər ‚in·tər·fə′räm·əd·ər]
An optical interferometer for measuring angular diameters of stars; it is attached to a telescope and measures interference rings at the telescope's focus.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Interferometer, Stellar


an astronomical optical instrument for the measurement of extremely small angular separations (tenths or hundredths of a second of arc) by using the phenomenon of interference of light. It is principally used to measure the angular separation between the components of close binary stars (components that are close in brightness) and the angular diameters of stars.

A distinction is made between simple and periscopic stellar interferometers. The first is an ordinary telescope with an opaque screen placed on the objective; the screen has two openings that are identical in form, for example, parallel slits. In this case interference fringes are observed on a star’s image; their appearance changes as the distance between the openings in the screen is changed and, in the case of binary stars, as a result of the mutual orientations of the line joining the components of the binary star and the openings in the screen. The simple stellar interferometer permits the resolving power of a telescope to be approximately doubled.

In the periscopic stellar interferometer, proposed by A. A. Michelson (USA), an optical system of two pairs of plane mirrors is mounted in front of the telescope’s objective, permitting two widely separated light rays from the source being measured to be directed into the telescope’s objective. This system increases the resolving power of the telescope in proportion to the distance between the outer mirrors. The angular diameters of several stars were measured for the first time in 1920–21 with the help of a periscopic stellar interferometer.


Martynov, D. la. Kurs prakticheskoi astrofiziki, 2nd ed. Moscow, 1967.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Scientists at the Institute for Research in Optical Communications and Microwaves, Limoges, France, just this year demonstrated how a single PBG fiber could replace four different optical fibers in an astronomical interferometer. Light at wavelengths from 670 nm to 1.5 [micro]m was simultaneously sent through a pair of single fibers, but because the transmission relies on the PBG and not index-guided propagation, the intensity was not affected by stretching one transmission leg, and the output of the two fibers was recombined with high-contrast fringes for all four wavelengths.
For this reason astronomical interferometers are often designed, not simply as linear arrays, but in two dimensions, as diamonds, hexagons, circles or crosses.

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