arXiv subjects

J. P. Cobos Carrascosa

Publications and source records attributed to J. P. Cobos Carrascosa.

4 recordsLinked to original sources

arXiv2026

The Sunrise Chromospheric Infrared Spectro-Polarimeter SCIP: an instrument for SUNRISE III

The Sunrise balloon-borne solar observatory is equipped with a one-meter aperture optical telescope, offering a unique platform for uninterrupted seeing-free observations across ultraviolet, visible, and infrared wavelengths from altitudes higher than 33 km. For the third flight of the upgraded Sunrise observatory conducted in 2024, now called Sunrise III, a new spectro-polarimeter called the Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) was developed for observing near-infrared wavelength ranges around 770 nm and 850 nm. These wavelength ranges contain many spectral lines, including two of the Ca II infrared triplet, K I D1 and D2 lines, and multiple Fe I lines, that are sensitive to solar magnetic fields and velocities in the photosphere and chromosphere. SCIP consists of a grating spectrograph in which polarimetric measurements are conducted using a rotating waveplate as a modulator and polarizing beam splitters placed in front of the cameras. The spatial and spectral resolutions are 0.21" and 1x10^5, respectively, and a polarimetric sensitivity of 0.03% (1sigma) of the continuum intensity is achieved with a 10 s integration time per a resolution element. To achieve high-precision detection of small polarization signals, we carefully designed the optical and mechanical systems, polarization components, control electronics, and onboard data processing. Together with the other post-focus instrumentation developed for Sunrise III, the Sunrise Ultraviolet Spectropolarimeter and Imager (SUSI) and the visible imaging spectro-polarimeter Tunable Magnetograph (TuMag), SCIP provides novel observations that help elucidate energy transfer and time-dependent phenomena across the solar photosphere and chromosphere.

astro-ph.SR↗

arXiv2025

TuMag: the tunable magnetograph for the Sunrise III mission

One of the instruments aboard the Sunrise III mission, the Tunable Magnetograph (TuMag), is a tunable imaging spectropolarimeter in visible wavelengths. It is designed to probe the vector magnetic field and the line-of-sight velocity of the photosphere and the lower chromosphere. The quasi-simultaneous observation of two spectral lines provides excellent diagnostic measurements of the magnetic and dynamic coupling in these layers. The key technologies employed for TuMag are an LCVR-based polarimeter and a solid, LiNbO3 Fabry-Pérot etalon as a spectrometer. However, it also incorporates several innovative features, such as home-made high-sensitivity scientific cameras and a double filter wheel. TuMag can sequentially observe any two out of the three spectral lines of Fe I at 525.02 and 525.06 nm and of Mg I at 517.3 nm. Laboratory measurements have demonstrated outstanding performance, including a wavefront root-mean-square error better than λ/13 for image quality, a full-width-at-half-maximum of 8.7 pm for the filtergraph transmission profile, and polarimetric efficiencies > 0.54. Here we report on the concept, design, calibration, and integration phases of the instrument, as well as on the data reduction pipeline.

astro-ph.IM↗

arXiv2019

Performance analysis of the SO/PHI software framework for on-board data reduction

The Polarimetric and Helioseismic Imager (PHI) is the first deep-space solar spectropolarimeter, on-board the Solar Orbiter (SO) space mission. It faces: stringent requirements on science data accuracy, a dynamic environment, and severe limitations on telemetry volume. SO/PHI overcomes these restrictions through on-board instrument calibration and science data reduction, using dedicated firmware in FPGAs. This contribution analyses the accuracy of a data processing pipeline by comparing the results obtained with SO/PHI hardware to a reference from a ground computer. The results show that for the analysed pipeline the error introduced by the firmware implementation is well below the requirements of SO/PHI.

astro-ph.IM↗

arXiv2018

Autonomous on-board data processing and instrument calibration software for the SO/PHI

The extension of on-board data processing capabilities is an attractive option to reduce telemetry for scientific instruments on deep space missions. The challenges that this presents, however, require a comprehensive software system, which operates on the limited resources a data processing unit in space allows. We implemented such a system for the Polarimetric and Helioseismic Imager (PHI) on-board the Solar Orbiter (SO) spacecraft. It ensures autonomous operation to handle long command-response times, easy changing of the processes after new lessons have been learned and meticulous book-keeping of all operations to ensure scientific accuracy. This contribution presents the requirements and main aspects of the software implementation, followed by an example of a task implemented in the software frame, and results from running it on SO/PHI. The presented example shows that the different parts of the software framework work well together, and that the system processes data as we expect. The flexibility of the framework makes it possible to use it as a baseline for future applications with similar needs and limitations as SO/PHI.

astro-ph.IM↗