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We report on a calibration procedure that enhances the precision of an interferometer based frequency stabilization by several orders of magnitude. For this purpose the frequency deviations of the stabilization are measured precisely by…

Optics · Physics 2012-08-14 Johannes F. S. Brachmann , Thomas Kinder , Kai Dieckmann

The star tracker is generally affected by the atmospheric background light and the aerodynamic environment when working in near space, which results in missing stars or false stars. Moreover, high-speed maneuvering may cause star trailing,…

Computer Vision and Pattern Recognition · Computer Science 2024-11-01 Shunmei Dong , Qinglong Wang , Haiqing Wang , Qianqian Wang

A long-held vision has been to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, and reveal interacting gas flows in binary systems. An…

Instrumentation and Methods for Astrophysics · Physics 2015-08-12 Dainis Dravins , Tiphaine Lagadec , Paul D. Nuñez

We present the astrometric calibration of the Beijing-Arizona Sky Survey (BASS). The BASS astrometry was tied to the International Celestial Reference Frame via the \emph{Gaia} Data Release 2 reference catalog. For effects that were stable…

Instrumentation and Methods for Astrophysics · Physics 2023-05-30 Xiyan Peng , Zhaoxiang Qi , Tianmeng Zhang , Zhenyu Wu , Zhimin Zhou , Jundan Nie , Hu Zou , Xiaohui Fan , Linhua Jiang , Ian McGreer , Jinyi Yang , Arjun Dey , Jun Ma , Jiali Wang , David Schlegel , Xu Zhou

Calibration, the practice of choosing the parameters of a structural model to match certain empirical moments, can be viewed as minimum distance estimation. Existing standard error formulas for such estimators require a consistent estimate…

Econometrics · Economics 2024-06-19 Matthew D. Cocci , Mikkel Plagborg-Møller

Up to now, the completion of an ALMA interferometric observation is determined based on the achievement of a given shape and size of the synthesized beam and the noise RMS in the representative spectral range. This approach with respect to…

Instrumentation and Methods for Astrophysics · Physics 2020-12-17 Dirk Petry , María Díaz Trigo , Rüdiger Kneissl , Ignacio Toledo , Stefano Facchini

In 21 cm cosmology, precision calibration is key to the separation of the neutral hydrogen signal from very bright but spectrally-smooth astrophysical foregrounds. The Hydrogen Epoch of Reionization Array (HERA), an interferometer…

We study the impact of sky-based calibration errors from source mismodeling on 21\,cm power spectrum measurements with an interferometer and propose a method for suppressing their effects. While emission from faint sources that are not…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Aaron Ewall-Wice , Joshua S. Dillon , Adrian Liu , Jacqueline Hewitt

We have built a reliable and robust system that takes as input an astronomical image, and returns as output the pointing, scale, and orientation of that image (the astrometric calibration or WCS information). The system requires no first…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 Dustin Lang , David W. Hogg , Keir Mierle , Michael Blanton , Sam Roweis

A class of methods for measuring time delays between astronomical time series is introduced in the context of quasar reverberation mapping, which is based on measures of randomness or complexity of the data. Several distinct statistical…

Instrumentation and Methods for Astrophysics · Physics 2017-08-16 Doron Chelouche , Francisco Pozo Nuñez , Shay Zucker

In this paper, we demonstrate light field triangulation to determine depth distances and baselines in a plenoptic camera. Advances in micro lenses and image sensors have enabled plenoptic cameras to capture a scene from different viewpoints…

Information Retrieval · Computer Science 2021-01-21 Christopher Hahne , Amar Aggoun , Vladan Velisavljevic , Susanne Fiebig , Matthias Pesch

We systematically investigate the error sources for high-precision astrometry from adaptive optics based near-infrared imaging data. We focus on the application in the crowded stellar field in the Galactic Center. We show that at the level…

Distributed calibration based on consensus optimization is a computationally efficient method to calibrate large radio interferometers such as LOFAR and SKA. Calibrating along multiple directions in the sky and removing the bright…

Instrumentation and Methods for Astrophysics · Physics 2021-10-29 Sarod Yatawatta

Many existing translation averaging algorithms are either sensitive to disparate camera baselines and have to rely on extensive preprocessing to improve the observed Epipolar Geometry graph, or if they are robust against disparate camera…

Computer Vision and Pattern Recognition · Computer Science 2019-01-04 Bingbing Zhuang , Loong-Fah Cheong , Gim Hee Lee

One of the main endeavors of fundamental astrometry is to establish a practical realization of an inertial reference frame anchored to celestial objects whose positions are defined in the barycentric coordinates of the solar system. The…

Astrophysics · Physics 2008-11-26 Sergei M. Kopeikin , Valeri V. Makarov

Astrometric calibration is based on patterns of cataloged stars and therefore effectively assumes a particular epoch, which can be substantially incorrect for historical images. With the known proper motions of stars we can "run back the…

Astrophysics · Physics 2009-11-13 Jonathan T. Barron , David W. Hogg , Dustin Lang , Sam Roweis

Measuring the quasar distance through joint analysis of spectroastrometry (SA) and reverberation mapping (RM) observations is a new method for driving the development of cosmology. In this paper, we carry out detailed simulation and…

High Energy Astrophysical Phenomena · Physics 2022-03-14 Ying-Ke Huang , Yue-Dong Fang , Kai-Xing Lu , Zhi-Xiang Zhang , Ji-Lin Liu , Sha-sha Li , Bao-Rui Luo , Qin Lin , Zhuo-Xi Huo

The parabolic structure of the secondary or conjugate spectra of pulsars is often the result of isolated one-dimensional (or at least highly anisotropic) lenses in the ISM. The curvature of these features contains information about the…

Instrumentation and Methods for Astrophysics · Physics 2023-07-11 Daniel Baker , Walter Brisken , Marten H. van Kerkwijk , Robert Main , Ue-Li Pen , Tim Sprenger , Olaf Wucknitz

Traditional radio interferometric correlators produce regular-gridded samples of the true $uv$-distribution by averaging the signal over constant, discrete time-frequency intervals. This regular sampling and averaging then translate to be…

Instrumentation and Methods for Astrophysics · Physics 2018-03-28 M. Atemkeng , O. Smirnov , C. Tasse , G. Foster , A. Keimpema , Z. Paragi , J. Jonas

An unbiased method for improving the resolution of astronomical images is presented. The strategy at the core of this method is to establish a linear transformation between the recorded image and an improved image at some desirable…

Astrophysics · Physics 2016-08-30 F. P. Pijpers