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A search for close separation (≲ 1″) quasar images

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The article was published on 1992-01-01. It has received 0 citations till now. The article focuses on the topics: Position angle & Quasar.

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Journal ArticleDOI

The importance of atmospheric differential refraction in spectrophotometry.

TL;DR: In this paper, the relation between object position and optimal slit or aperture orientation is derived, and practical tables and graphs are presented for use at the telescope, where the relative line and continuum intensities in spectrophotometric work may be erroneous if this phenomenon is neglected.
Journal ArticleDOI

The Statistics of gravitational lenses: The Distributions of image angular separations and lens redshifts

TL;DR: In this article, an analytical calculation is presented which determines the probability that the light from a distant quasar can be lensed by objects in a different redshift range, and a number of recommendations are offered with respect to VLA and Space Telescope observations of quasars lensed.
Journal ArticleDOI

Automatic Analysis of Crowded Fields

TL;DR: There are many important 2D data reduction problems in Astronomy that are not amenable to conventional automatic analysis as mentioned in this paper, typically these problem areas arise in fields where the number density of images is high and where the local sky background may vary rapidly.
Journal ArticleDOI

An optical catalog of quasi-stellar objects

TL;DR: In this article, a catalog of all known quasi-stellar objects with measured emission redshifts, and BL Lac objects, complete to September 1986, is presented, comprising 3681 objects, comprising 3594 QSOs and 87 BL Lac Objects.
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