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A long-standing issue in solar ground-based observations has been the contamination of data due to stray light, which is particularly relevant in inversions of spectropolarimetric data. We aim to build on a statistical method of correcting…

Solar and Stellar Astrophysics · Physics 2021-12-07 Sudharshan Saranathan , Michiel van Noort , Sami K. Solanki

Observations of the Sun from the Earth are always limited by the presence of the atmosphere, which strongly disturbs the images. A solution to this problem is to place the telescopes in space satellites, which produce observations without…

Solar and Stellar Astrophysics · Physics 2015-06-24 C. Quintero Noda , A. Asensio Ramos , D. Orozco Suárez , B. Ruiz Cobo

Context. Accurate photometry with ground based solar telescopes requires characterization of straylight. Scattering in Earth's atmosphere and in the telescope optics are potentially significant sources of straylight, for which the point…

Solar and Stellar Astrophysics · Physics 2016-01-13 Mats G. Löfdahl

Recently measured straylight PSFs in Hinode/SOT make granulation contrast in observed data and synthetic MHD data consistent. Data from earthbound telescopes also need accurate correction for straylight and fixed optical aberrations. We aim…

Instrumentation and Methods for Astrophysics · Physics 2012-01-16 M. G. Löfdahl , G. B. Scharmer

We report a point spread function (PSF) and deconvolution procedure to remove stray light from the Helioseismic and Magnetic Imager (HMI) data. Pre-launch calibration observations, post-launch Venus transit and lunar transit data were used…

Solar and Stellar Astrophysics · Physics 2025-11-18 A. A. Norton , T. L. Duvall, , J. Schou , R. S. Bogart , J. Zhao , C. Rabello-Soares , P. J. Levens , J. T. Hoeksema , C. S. Baldner

Stray light significantly influences the detection capabilities of astronomical telescopes. The actual stray-light level during observations depends not only on the telescope's inherent stray-light suppression capability but also on its…

Instrumentation and Methods for Astrophysics · Physics 2025-11-11 Xian Jing-Tian , Lin Lin , Fang Yue-Dong , Zhang Xin , Xu You-Hua , Meng Xian-Min , Tian Hao , Zhang Tian-Yi , Ban Zhang , Li Guo-Liang , Xu Shu-Yan , Wang Wei

One of the major limitations of adaptive optics (AO) corrected image post-processing is the lack of knowledge on the system point spread function (PSF). The PSF is not always available as a direct imaging on isolated point like objects such…

Instrumentation and Methods for Astrophysics · Physics 2020-07-22 Romain Fétick , Laurent Mugnier , Thierry Fusco , Benoit Neichel

Context: Characterization of instrumental effects in astronomical imaging is important in order to extract accurate physical information from the observations. The measured image in a real optical instrument is usually represented by the…

Computer Vision and Pattern Recognition · Computer Science 2016-01-12 Adriana Gonzalez , Véronique Delouille , Laurent Jacques

The spatial resolution of astronomical images is limited by atmospheric turbulence and diffraction in the telescope optics, resulting in blurred images. This makes it difficult to accurately measure the brightness of blended objects because…

Instrumentation and Methods for Astrophysics · Physics 2023-05-31 Kevin Michalewicz , Martin Millon , Frédéric Dux , Frédéric Courbin

The number of satellites on low orbit has dramatically increased over the past years, raising concerns among the astronomical community about their impact on observations. Spectroscopic observations represent a large fraction of…

Instrumentation and Methods for Astrophysics · Physics 2024-01-19 Olivier R. Hainaut Sabine Moehler

Anisoplanatic effects can cause significant systematic photometric uncertainty in the analysis of dense stellar fields observed with adaptive optics. Program packages have been developed for a spatially variable PSF, but they require that a…

Instrumentation and Methods for Astrophysics · Physics 2009-12-08 R. Schoedel

In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in…

Numerical Analysis · Mathematics 2015-06-09 M. Prato , A. La Camera , S. Bonettini , S. Rebegoldi , M. Bertero , P. Boccacci

The contrasts of features in the quiet Sun are studied using filtergrams recorded by the Broad-band Filter Imager on the Hinode/Solar Optical Telescope. In a first step, the scattered light originating in the instrument is modeled using…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. K. Mathew , V. Zakharov , S. K. Solanki

Removing the aberrations introduced by the Point Spread Function (PSF) is a fundamental aspect of astronomical image processing. The presence of noise in observed images makes deconvolution a nontrivial task that necessitates the use of…

Instrumentation and Methods for Astrophysics · Physics 2017-05-03 Samuel Farrens , Jean-Luc Starck , Fred Maurice Ngolè Mboula

Access to knowledge of the point spread function (PSF) of adaptive optics(AO)-assisted observations is still a major limitation when processing AO data. This limitation is particularly important when image analysis requires the use of…

Instrumentation and Methods for Astrophysics · Physics 2023-05-10 A. Lau , R. JL. Fétick , B. Neichel , O. Beltramo-Martin , T. Fusco

A method for spatial deconvolution of spectra is presented. It follows the same fundamental principles as the ``MCS image deconvolution algorithm'' (Magain, Courbin, Sohy, 1998) and uses information contained in the spectrum of a reference…

Astrophysics · Physics 2009-10-31 F. Courbin , P. Magain , M. Kirkove , S. Sohy

We demonstrate spectroscopy of incoherent light with sub-diffraction resolution. In a proof-of-principle experiment we analyze the spectrum of a pair of incoherent point-like sources whose separation is below the diffraction limit. The two…

This paper demonstrates a practical method that can correct spatial varying blur from a set of images of the same object. The algorithm jointly estimates the object and local point spread functions~(PSF). The method prioritizes sections…

Image and Video Processing · Electrical Eng. & Systems 2020-11-04 Wouter van de Ketterij , Oleg Soloviev , Michel Verhaegen

We present a semi-blind, spatially-variant deconvolution technique aimed at optical microscopy that combines a local estimation step of the point spread function (PSF) and deconvolution using a spatially variant, regularized Richardson-Lucy…

Computer Vision and Pattern Recognition · Computer Science 2019-05-21 Adrian Shajkofci , Michael Liebling

The aim of this work is to quantify the amount of Earth stray light that reaches the CHEOPS (CHaracterising ExOPlanets Satellite) detector. It will carry out follow-up measurements on transiting planets. This requires exquisite data that…

Instrumentation and Methods for Astrophysics · Physics 2013-10-30 Thibault Kuntzer
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