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Related papers: Atmospheric time constant with MASS and FADE

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We present a simple method of extracting a small number of reference optical turbulence and wind profiles from a large dataset for single conjugate and extreme adaptive optics simulations. These reference profiles can be used in slow…

Instrumentation and Methods for Astrophysics · Physics 2022-10-18 O. J. D. Farley

The Multi Aperture Scintillation Sensor (MASS) and the Generalized-Scintillation Detection and Ranging (Generalized SCIDAR) are two instruments conceived to measure the optical turbulence (OT) vertical distribution on the whole troposphere…

Instrumentation and Methods for Astrophysics · Physics 2013-11-12 E. Masciadri , G. Lombardi , F. Lascaux

The atmospheric scintillation of stars is the main limitation of the accuracy of ground-based photometry of astronomical objects. This becomes particularly noticeable for a study of a variability with amplitudes on the order to thousandths…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Victor Kornilov

Fast timing detectors are an essential element in the experimental setup for time-of-flight (ToF) mass measurements of unstable nuclei. We have upgraded the scintillator detectors used in experiments at the National Superconducting…

A new method for examining the possible space-time variation of the fine structure constant ($\alpha$) is proposed. The technique uses a relatively simple measurement with an optical resonator to compare atom-stabilized optical frequency…

Atomic Physics · Physics 2007-05-23 J. R. Torgerson

We study the fixed angle inverse scattering problem of determining a sound speed from scattering measurements corresponding to a single incident wave. The main result shows that a sound speed close to constant can be stably determined by…

Analysis of PDEs · Mathematics 2023-04-25 Shiqi Ma , Leyter Potenciano-Machado , Mikko Salo

Since the year 2000, adaptive optics (AO) has seen the emergence of a variety of new concepts addressing particular science needs; multiconjugate adaptive optics (MCAO) is one of them. By correcting the atmospheric turbulence in 3D using…

Instrumentation and Methods for Astrophysics · Physics 2020-03-09 Francois Rigaut , Benoit Neichel

We present low-resolution turbulence profiles of the atmosphere above Dome C, Antarctica, measured with the MASS instrument during 25 nights in March-May 2004. Except for the lowest layer, Dome C has significantly less turbulence than Cerro…

Astrophysics · Physics 2009-11-11 S. L. Kenyon , J. S. Lawrence , M. C. B. Ashley , J. W. V. Storey , A. Tokovinin , E. Fossat

The carbon to oxygen (C/O) abundance ratio is a valuable tracer of star formation history, as C and O enrichment occurs on different timescales. However, measurements based on ultraviolet (UV) collisionally excited lines and those based on…

Timing-pick up detectors with excellent timing resolutions are essential in many modern nuclear physics experiments. Aiming to develop a Time-Of-Flight system with precision down to about 10 ps, we have made a systematic study of the timing…

Instrumentation and Detectors · Physics 2016-04-19 J. W. Zhao , B. H. Sun , I. Tanihata , S. Terashima , L. H. Zhu , A. Enomoto , D. Nagae , T. Nishimura , S. Omika , A. Ozawa , Y. Takeuchi , T. Yamaguchi

Time of Flight methods have been rapidly developed and used in many experiments recently for determination of particle direction, identification of particles and energy resolutions. This paper describes a method of time-mark determination…

Instrumentation and Detectors · Physics 2019-09-19 Ali Yilmaz

We demonstrate experimentally and numerically that the application of a partially coherent beam (PCB) in combination with time averaging leads to a significant reduction in the scintillation index. We use a simplified experimental approach…

Time-delay error is a significant error source in adaptive optics (AO) systems. It arises from the latency between sensing the wavefront and applying the correction. Predictive control algorithms reduce the time-delay error, providing…

Instrumentation and Methods for Astrophysics · Physics 2024-06-27 Jalo Nousiainen , Juha-Pekka Puska , Tapio Helin , Nuutti Hyvönen , Markus Kasper

We demonstrate the measurement of mass of the absorbing micro-particle trapped in air by optical forced oscillation. When the trapping light intensity is modulated sinusoidally, the particle in the trap undergoes forced oscillation and the…

Optics · Physics 2017-06-28 Jinda Lin , Jianliao Deng , Rong Wei , Yong-qing Li , Yuzhu Wang

We analyse the time-dependence of currents in a 1D Bose gas in an optical lattice. For a 1D system, the stability of currents induced by accelerating the lattice exhibits a broad crossover as a function of the magnitude of the acceleration,…

Quantum Gases · Physics 2010-03-03 Johannes Schachenmayer , Guido Pupillo , Andrew J. Daley

One important frontier for astronomical adaptive optics (AO) involves methods such as Multi-Object AO and Multi-Conjugate AO that have the potential to give a significantly larger field of view than conventional AO techniques. A second key…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 S. Mark Ammons , Luke Johnson , Edward A. Laag , Renate Kupke , Donald T. Gavel , Brian J. Bauman , Claire E. Max

Context. Adaptive optics (AO) is now a tool commonly deployed in astronomy. The real time correction of the atmospheric turbulence that AO enables allows telescopes to perform close to the diffraction limit at the core of their point spread…

Instrumentation and Methods for Astrophysics · Physics 2023-06-21 Anthony Berdeu , Michel Tallon , Éric Thiébaut , Maud Langlois

For high-contrast imaging (HCI) systems, such as VLT/SPHERE, the performance of the system at small angular separations is contaminated by the wind-driven halo in the science image. This halo is a result of the servo-lag error in the…

Instrumentation and Methods for Astrophysics · Physics 2020-04-22 M. A. M. van Kooten , Niek Doelman , Matthew Kenworthy

Adaptive Optics (AO) systems have become integral for ground-based astronomy. Based on the scientific case, there are various flavours of AO systems. Measuring the turbulence strength profile ($C_N^2(h)$) and other site characteristics is…

Instrumentation and Methods for Astrophysics · Physics 2023-10-19 Saraswathi Kalyani Subramanian , Sridharan Rengaswamy

Ground-based solar observations are severely affected by Earth's turbulent atmosphere. As a consequence, observed image quality and prevailing seeing conditions are closely related. Partial correction of image degradation is nowadays…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Robert Kamlah , Meetu Verma , Andrea Diercke , Carsten Denker