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Due to limited size and imperfect of the optical components in a spectrometer, aberration has inevitably been brought into two-dimensional multi-fiber spectrum image in LAMOST, which leads to obvious spacial variation of the point spread…

Instrumentation and Methods for Astrophysics · Physics 2020-10-28 Jiali Xu , Qian Yin , Ping Guo , Xin Zheng

The iterative refinement method (IRM) has been very successfully applied in many different fields for examples the modern quantum chemical calculation and CT image reconstruction. It is proved that the refinement method can create an exact…

Medical Physics · Physics 2015-12-23 Kang Yang , Kevin Yang , Xintie Yang , Shuang-Ren Zhao

Context. Remote sensing of weak and small-scale solar magnetic fields is of utmost relevance for a number of important open questions in solar physics. This requires the acquisition of spectropolarimetric data with high spatial resolution…

Instrumentation and Methods for Astrophysics · Physics 2016-05-18 F. A. Iglesias , A. Feller , K. Nagaraju , S. K. Solanki

Herschel/SPIRE Fourier transform spectrometer (FTS) observations contain emission from both the Herschel Telescope and the SPIRE Instrument itself, both of which are typically orders of magnitude greater than the emission from the…

A novel technique for calibration transfer called the Modified Four Point Interpolant (MFPI) method is introduced for near infrared spectra. The method is founded on physical intuition and utilizes a series of quasiconformal maps in the…

Applications · Statistics 2017-02-01 Casey Kneale , Karl S. Booksh

We investigate the cross-calibration of the Hinode/SOT-SP and SDO/HMI instrument meta-data, specifically the correspondence of the scaling and pointing information. Accurate calibration of these datasets gives the correspondence needed by…

Scientific data reduction on-board deep space missions is a powerful approach to maximise science return, in the absence of wide telemetry bandwidths. The Polarimetric and Helioseismic Imager (PHI) on-board the Solar Orbiter (SO) is the…

Context: Data from ground-based, high-resolution solar telescopes can only be used for science with calibrations and processing, which requires detailed knowledge about the instrumentation. [...] Aims: We aim to provide observers with a…

Instrumentation and Methods for Astrophysics · Physics 2021-09-29 M. G. Löfdahl , T. Hillberg , J. de la Cruz Rodriguez , G. Vissers , O. Andriienko , G. B. Scharmer , S. V. H. Haugan , T. Fredvik

When using valid foreground and signal models, the uncertainties on extracted signals in global 21-cm signal experiments depend principally on the overlap between signal and foreground models. In this paper, we investigate two strategies…

Instrumentation and Methods for Astrophysics · Physics 2020-07-22 Keith Tauscher , David Rapetti , Jack O. Burns

The findings of a nine orbit calibration plan carried out during HST Cycle 15, to fully determine the NICMOS camera 2 (2.0 micron) polarization calibration to high accuracy, are reported. Recently Ueta et al. and Batcheldor et al. have…

In radio astronomy, visibility data, which are measurements of wave signals from radio telescopes, are transformed into images for observation of distant celestial objects. However, these resultant images usually contain both real sources…

Instrumentation and Methods for Astrophysics · Physics 2023-11-29 Ruoqi Wang , Zhuoyang Chen , Jiayi Zhu , Qiong Luo , Feng Wang

We observed Proxima Centauri with the Spitzer Space Telescope InfraRed Array Camera (IRAC) five times in 2016 and 2017 to search for transits of Proxima Centauri b. Following standard analysis procedures, we found three asymmetric,…

Context. The current algorithms used for the calibration and analysis of very long baseline interferometry (VLBI) networks that only use linear polarizers (as is the case of the VLBI Global Observing System, VGOS) do not properly account…

Instrumentation and Methods for Astrophysics · Physics 2024-06-19 V. Pérez-Díez , I. Martí-Vidal , E. Albentosa-Ruiz , J. González-García , F. Jaron , T. Savolainen , M. H. Xu , R. Bachiller

The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this…

Solar and Stellar Astrophysics · Physics 2012-04-23 Jaime de la Cruz Rodríguez

The Segmented Planar Imaging Detector for Electro-Optical Reconnaissance (SPIDER) is an optical interferometric imaging device that aims to offer an alternative to the large space telescope designs of today with reduced size, weight and…

Instrumentation and Methods for Astrophysics · Physics 2024-01-17 Matthijs Mars , Marta M. Betcke , Jason D. McEwen

Determination of solar magnetic fields with a spatial resolution set by the diffraction limit of a telescope is difficult because the time required to measure the Stokes vector with sufficient signal-to-noise is long compared to the solar…

Solar and Stellar Astrophysics · Physics 2024-05-08 Jaime de la Cruz Rodríguez , Jorrit Leenaarts

The Near-IR Imaging Spectropolarimeter (NIRIS) is a polarimeter that is installed at the New Solar Telescope at Big Bear Solar Observatory. This instrument takes advantages of the highest spatial resolution and flux. The primary mirror is…

Instrumentation and Methods for Astrophysics · Physics 2019-10-01 Kwangsu Ahn , Wenda Cao

The Colour and Stereo Surface Science Imaging System (CaSSIS) of the ExoMars Trace Gas Orbiter returns on average twenty images per day of the Martian surface, most of them in 3 or 4 colours and some of them in stereo. CaSSIS uses a…

Data products from high spectral resolution astronomical polarimeters are often limited by fringes. Fringes can skew derived magnetic field properties from spectropolarimetric data. Fringe removal algorithms can also corrupt the data if the…

Instrumentation and Methods for Astrophysics · Physics 2018-03-28 David M. Harrington , Stacey R. Sueoka

The constant improvement of astronomical instrumentation provides the foundation for scientific discoveries. In general, these improvements have only implications forward in time, while previous observations do not benefit from this trend.…

Solar and Stellar Astrophysics · Physics 2025-05-29 Robert Jarolim , Astrid M. Veronig , Werner Pötzi , Tatiana Podladchikova