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I derive in this paper theoretical expressions for biases on fringe contrast and fringe visibility phase for optical interferometers whose polarizing properties can be described by beam rotation, retardance, and diattenuation. The nature of…

Instrumentation and Methods for Astrophysics · Physics 2025-04-07 Guy Perrin

The spherometer used for measuring radius of curvature of spherical surfaces is explicitly based on a geometric relation unique to circles and spheres. We present an alternate approach using coordinate geometry, which reproduces the…

General Physics · Physics 2013-09-10 Sameen Ahmed Khan

Very long baseline interferometry (VLBI) provides the resolution needed to make precision measurements of a pulsar's parallax and proper motion. In making these measurements, the astronomer is faced with difficult calibration problems and a…

Astrophysics · Physics 2007-05-23 Walter Brisken

Various sign-posts of recent star-formation activity, such as water and methanol maser emission or magnetically active low-mass young stars, can be detected with Very Long Baseline Interferometry (VLBI) radio arrays. The extremely accurate…

Astrophysics of Galaxies · Physics 2018-10-17 Laurent Loinard , Mark J. Reid

This tutorial gives a general introduction to optical and infrared interferometry, specifically addressing two questions: `Can I use VLTI to observe my favourite object?' and `What will it tell me?' The observables measured by an…

Astrophysics · Physics 2007-05-23 Timothy R. Bedding

This paper studies the problem of identifying directions of axial symmetry in multivariate distributions. Theoretical results are derived on how the measure or cardinality of the set of symmetry directions relates to spherical symmetry. The…

Statistics Theory · Mathematics 2025-12-29 Alejandro Cholaquidis , Ricardo Fraiman , Manuel Hernández-Banadik , Stanislav Nagy

The high accuracy of modern space astrometry requires the use of General Relativity to model the propagation of stellar light through the gravitational field encountered from a source to a given observer inside the Solar System. In this…

General Relativity and Quantum Cosmology · Physics 2009-02-17 Mariateresa Crosta , Alberto Vecchiato

Grassmann tensors arise from classical problems of scene reconstruction in computer vision. Trifocal Grassmann tensors, related to three projections from a projective space of dimension k onto view-spaces of varying dimensions are studied…

Algebraic Geometry · Mathematics 2019-07-25 Marina Bertolini , Gian Mario Besana , Gilberto Bini , Cristina Turrini

Optical spectropolarimeters can be used to produce maps of the surface magnetic fields of stars and hence to determine how stellar magnetic fields vary with stellar mass, rotation rate, and evolutionary stage. In particular, we now can map…

Solar and Stellar Astrophysics · Physics 2015-05-20 S. G. Gregory

In this work, we show that by combining quantum metrology and networking tools, it is possible to extend the baseline of an interferometric optical telescope and thus improve diffraction-limited imaging of point source positions. The…

Quantum Physics · Physics 2023-04-25 Marta Maria Marchese , Pieter Kok

Improved quantum sensing of photons from astronomical objects could provide high resolution observations in the optical benefiting numerous fields, including general relativity, dark matter studies, and cosmology. It has been recently…

Instrumentation and Methods for Astrophysics · Physics 2022-11-03 Paul Stankus , Andrei Nomerotski , Anže Slosar , Stephen Vintskevich

A method for calculating the meridian profile of the aspherical surface of a plane-convex lens excluding spherical aberration, without calculating the coefficients of the series, by direct solving the compiled differential equation is…

Instrumentation and Methods for Astrophysics · Physics 2017-05-04 Ilia Evteev

The new method of invariant definition of the measurable angle of light deflection in the static central symmetric gravitational field is suggested. The predicted pure gravitational contribution to the deflection angle slightly differs from…

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. Tertychniy

Astronomers usually need the highest angular resolution possible, but the blurring effect of diffraction imposes a fundamental limit on the image quality from any single telescope. Interferometry allows light collected at widely-separated…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John D. Monnier , Ronald J. Allen

The basic effect of the earth's atmospheric refraction on telescope operation is the reduction of the true zenith angle to the apparent zenith angle, associated with prismatic aberrations due to the dispersion in air. If one attempts…

Astrophysics · Physics 2007-05-23 Richard J. Mathar

This article gives the construction and complete classification of all three-dimensional spherical manifolds, and orders them by decreasing volume, in the context of multiconnected universe models with positive spatial curvature. It…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Evelise Gausmann , Roland Lehoucq , Jean-Pierre Luminet , Jean-Philippe Uzan , Jeffrey Weeks

Radio polarization measurements of pulsed emission from pulsars offer a valuable insight into the basic geometry of the neutron star: inclination angle between the magnetic and rotation axis and inclination of the line of sight. So far, all…

High Energy Astrophysical Phenomena · Physics 2017-01-11 J. Pétri

It is believed that some numerical technique must be employed for the determination of the system parameters of a visual binary or a star with a planet because the relevant equations are not only highly nonlinear but also transcendental…

Astrophysics · Physics 2015-06-24 Hideki Asada , Toshio Akasaka , Masumi Kasai

Context: In recent years, stellar intensity interferometry has seen renewed interest from the astronomical community because it can be efficiently applied to Cherenkov telescope arrays. Aims: We have investigated the accuracy that can be…

Instrumentation and Methods for Astrophysics · Physics 2022-10-05 Michele Fiori , Giampiero Naletto , Luca Zampieri , Irene Jiménez Martínez , Carolin Wunderlich

The calibration process of long baseline stellar interferometers requires the use of reference stars with accurately determined angular diameters. We present a catalog of 374 carefully chosen stars among the all-sky network of infrared…

Astrophysics · Physics 2015-06-24 Pascal Borde , Vincent Coude du Foresto , Gilles Chagnon , Guy Perrin