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Related papers: Two-mirror Schwarzschild aplanats. Basic relations

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It is shown that in polar geometry and normal incidence the 2x2 matrix technique - as discussed in detail in a preceeding paper [Phys. Rev. B 65, 144448 (2002)] - accounts correctly for multiple reflections and optical interferences, and…

Materials Science · Physics 2009-11-07 A. Vernes , L. Szunyogh , P. Weinberger

Two people who pioneered the study of mapping class group-equivariant deformation retractions of Teichm\"uller space of closed compact surfaces are Schmutz Schaller and Thurston. This paper studies how the two different approaches are dual…

Geometric Topology · Mathematics 2025-08-07 Ingrid Irmer

We first define what we mean by gravitational lensing equations in a general space-time. A set of exact relations are then derived that can be used as the gravitational lens equations in all physical situations. The caveat is that into…

General Relativity and Quantum Cosmology · Physics 2008-12-18 Simonetta Frittelli , Ezra T. Newman

We propose a form of a lens corrector at the prime focus of a hyperboloidal mirror that provides a flat field of view up to 3 deg diameter at image quality D_{80} < 0.8 arcsec in integrated (0.32-1.10 mcm) light. The corrector consists of…

Astrophysics · Physics 2014-10-13 V. Yu. Terebizh

We survey explicit coordinate descriptions for two (A and X) versions of Teichmuller and lamination spaces for open 2D surfaces, and extend them to the more general set-up of surfaces with distinguished collections of points on the…

Differential Geometry · Mathematics 2007-05-23 V. V. Fock , A. B. Goncharov

The content of this review is summarized here through the titles of its sections, as follows: 1. Introduction: Schwarzschild's original solution and the ``Schwarzschild solution''. 2. The wrong arrow of time of Hilbert's manifold is at the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Salvatore Antoci , Dierck-Ekkehard Liebscher

Wide-Field Corrector designs are presented for the Blanco and Mayall telescopes, the CFHT and the AAT. The designs are Terezibh-style, with 5 or 6 lenses, and modest negative optical power. They have 2.2-3 degree fields of view, with curved…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Will Saunders , Peter Gillingham , Greg Smith , Steve Kent , Peter Doel

There are two basic angles associated with a pair of linear subspaces: the Diximier angle and the Friedrichs angle. The Dixmier angle of the pair of orthogonal complements is the same as the Dixmier angle of the original pair provided that…

Functional Analysis · Mathematics 2021-09-23 Heinz H. Bauschke , Hui Ouyang , Xianfu Wang

We present a complete analysis of the light rays within the linearized, weak-field approximation of a Schwarzschild-like metric describing the gravitational field of an isolated, spherically symmetric body. We prove in this context the…

General Relativity and Quantum Cosmology · Physics 2016-02-17 Bernard Linet , Pierre Teyssandier

Dual image formation for a two-dimensional object via bimodal propagation through chiral-dispersive thick lens is derived. In this article, first-order frequency-dependent material dispersion of the dielectric permittivity and the lens…

Image and Video Processing · Electrical Eng. & Systems 2025-05-06 Salaheddeen Bugoffa , Hussin Ragb

Let $\underline{x} = x_1,\ldots,x_k$ denote an ordered sequence of elements of a commutative ring $R$. Let $M$ be an $R$-module. We recall the two notions that $\underline{x}$ is $M$-proregular given by Greenlees and May (see \cite{[5]})…

Commutative Algebra · Mathematics 2020-09-25 Peter Schenzel

In 1933 von Neumann proved a beautiful result that one can approximate a point in the intersection of two convex sets by alternating projections, i.e., successively projecting on one set and then the other. This algorithm assumes that one…

Optimization and Control · Mathematics 2026-04-09 Gábor Braun , Sebastian Pokutta , Robert Weismantel

The next generation of telescopes will usher in an era of precision cosmology, capable of determining the cosmological model to beyond the percent level. For this to be effective, the theoretical model must be understood to at least the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Obinna Umeh , Chris Clarkson , Roy Maartens

The transition of the binary gravitational lens from the equal mass case to small (planetary) mass ratios q is studied. It is shown how the limit of a (pure shear) Chang-Refsdal lens is approached, under what conditions the Chang-Refsdal…

Astrophysics · Physics 2009-09-25 M. Dominik

The classical uniformization theorem states that any simply connected Riemann surface is conformally equivalent to the disk, the plane, or the sphere, each equipped with a standard conformal structure. We give a similar uniformization for…

Metric Geometry · Mathematics 2014-02-26 Kevin Wildrick

A short formula is suggested which approximates photon trajectories in the Schwarzschild field better than other simple prescriptions from the literature. We compare it with various "low-order competitors", namely with those following from…

High Energy Astrophysical Phenomena · Physics 2015-02-13 Oldrich Semerak

Ancient instruments of high interest for research on the origin and diffusion of early scientific devices in the late XVI - early XVII centuries are reproduced in three paintings by Jan Brueghel the Elder. We investigated the nature and the…

Instrumentation and Methods for Astrophysics · Physics 2015-12-07 Pierluigi Selvelli , Paolo Molaro

Several early spyglasses are depicted in five paintings by Jan Brueghel the Elder completed between 1608 and 1625, as he was court painter of Archduke Albert VII of Habsburg. An optical tube that appears in the Extensive Landscape with View…

Instrumentation and Methods for Astrophysics · Physics 2009-09-30 Paolo Molaro , Pierluigi Selvelli

Astrophysical lensing has typically been studied in two regimes: diffractive optics and refractive optics. Diffractive optics is characterized by a perturbative expansion of the Kirchhoff-Fresnel diffraction integral, while refractive…

High Energy Astrophysical Phenomena · Physics 2023-08-09 Dylan L. Jow , Ue-Li Pen , Job Feldbrugge

It is has been long known that the curved space in the presence of gravitation can be described as a non-homogeneous anisotropic medium in flat geometry with different constitutive equations. In this article, we show that the…

General Relativity and Quantum Cosmology · Physics 2010-02-03 Sina Khorasani , Bizhan Rashidian