arXiv subjects

Oliver Pineda Suárez

Publications and source records attributed to Oliver Pineda Suárez.

5 recordsLinked to original sources

arXiv2026

Performance Testing of a Trillium-based 21-Positioner Module for Stage-5 Telescopes

Evaluating the performance metrics of theta-phi robotic positioners is crucial to gather insights into the system's behavior and ensure their reliability during operation in Stage-5 telescopes such as the Chinese MUST, the American Spec-S5 and the European WST. With a careful analysis of these metrics, a comprehensive characterization of the system's strengths is obtained, alongside a clear identification of aspects requiring improvement. Thus, providing potential avenues for streamlining and optimizing its design and functionality. In this paper we present the results of the positioning performance and angular tilt tests conducted on 6.2-mm pitch robotic positioner modules developed for high-density fiber positioning in next-generation astronomical systems. The fiber positioners from the tested prototype adopt a mechanical design based on the Trillium open design from the Lawrence Berkeley National Laboratory (LBNL) and were produced by the Japanese company Orbray. The evaluated performance metrics of positioning repeatability, datum repeatability, backlash, non-linearity, and angular tilt were measured and compared to the desired performance for Stage-5 telescopes. The positioners exhibited a generally acceptable performance, although noticeable anomalies affecting several metrics were identified and will require mitigation in subsequent prototypes. Nevertheless, the results indicate promising performance suitable for Stage-5 telescope instrumentation, provided that these issues are successfully resolved.

astro-ph.IM↗

arXiv2026

Testing of a 15-Positioner Module Based on the MPS Design for Stage-5 Telescopes

Assessing the performance metrics of theta-phi micro-robotic positioners is a key step toward understanding their operational behavior and ensuring that they meet the specifications of Stage-5 astronomical facilities, including the Chinese MUST, the American Spec-S5, and the European WST. A detailed examination of these metrics enables a clear evaluation of the system's current capabilities while also revealing aspects that require further refinement, which in turn guides improvements in design and manufacturing. In this work, carried out in collaboration with Micro Precision Systems (MPS) in Switzerland, we present the results of positioning performance and angular tilt characterization conducted on a 6.2-mm-pitch robotic positioner module developed for high-density fiber placement in next-generation spectroscopic instruments. The prototype unit evaluated in this study was produced by MPS. The measured metrics, including positioning repeatability, datum repeatability, backlash, non-linearity, and angular tilt, are compared directly with the nominal performance targets defined for Stage-5 telescope systems.

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arXiv2026

WST Multi-Object Spectrograph Fiber Positioners:Development of a 32,000-Unit Precision Robotic System

The Wide-field Spectroscopic Telescope Multi-Object Spectrograph requires an unprecedented fiber positioning system comprising 30'000 low-resolution and 2'000 high-resolution positioners across a 3.1 deg squared field of view. Each robotic positioner must achieve 5um RMS positioning accuracy in a densely packed focal plane, representing a more than sixfold scale increase over current instruments like 4MOST and DESI. To mitigate risks associated with industrial-scale production of 32'000 precision mechanisms, WST is pursuing a multi-concept development strategy. Four distinct positioner architectures are being prototyped and tested by an international collaboration (EPFL, AIP, UKATC, AAO) using 6.2 mm pitch triangular modules of 63 units each or a new inline modular concept. Performance metrics including positioning accuracy, repeatability, reconfiguration speed, collision avoidance, and manufacturability are being systematically evaluated. Down-selection to one or two concepts is planned for 2026-2027 during the HORIZON Europe-funded conceptual study phase. Current prototype testing demonstrates feasibility of meeting specifications, supporting WST's path toward first light in the early 2040s as ESO's next major spectroscopic facility.

astro-ph.IM↗

arXiv2026

Comparative Study of Hollow-Core and Standard Optical Fibers for Astronomy

Efficient light transmission in the blue-visible regime remains a major limitation for fiber-fed astronomical spectrographs, where low photon flux and the intrinsic attenuation of conventional silica fibers reduce survey sensitivity and depth. Inhibited-coupling hollow-core fibers (IC-HCFs) with reduced surface roughness offer a promising alternative, providing guidance predominantly in air and enabling significantly lower loss across the visible spectrum. In this study, we present a comparative evaluation of IC-HCFs against standard multi-mode fibers used in current astronomical instrumentation. We assess the throughput loss that occurs due to bending, twisting, or pinching of the optical fibers when moved using one of the robotic fiber-positioner prototypes designed for next-generation telescopes. These measurements quantify the performance gains offered by IC-HCFs for blue-sensitive spectroscopy and assess their suitability for integration into future survey facilities.

astro-ph.IM↗

arXiv2026

Prototyping of 6.2-mm-Pitch Fiber Positioner Modules for Stage-V Telescope Instrumentation

Small-pitch populated focal planes are essential enabling technologies for the next generation of highly multiplexed astronomical instruments. As modern astrophysics relies on massive spectroscopic surveys to study dark energy, dark matter, and galactic assembly, the ability to observe thousands of targets simultaneously has become paramount. To achieve these ambitious scientific goals, optical fibers must be packed into the telescope's focal plane with unprecedented density and accuracy. This work reports on comprehensive prototyping activities for novel 6.2 mm-pitch alpha-beta (theta-phi) fiber positioner modules. Achieving reliable operation at this extremely miniaturized scale presents formidable mechanical and control-system challenges. We provide a detailed comparative analysis of two primary architectural approaches: trillium-based mechanisms and independently actuated robotic designs. A rigorous quantitative assessment was conducted for both prototype models. Critical metrics such as XY positioning repeatability, non-linearity, and gear backlash were evaluated, as these directly dictate the targeting accuracy of the fiber on the sky. Furthermore, we analyzed fiber tilt angles, a crucial factor given its severe implications for Focal Ratio Degradation and the subsequent loss of optical throughput to the spectrographs. Our analysis contextualizes these mechanical constraints with their direct implications for overall instrument performance and survey efficiency. Initial results are highly encouraging, indicating that these miniaturized positioners can successfully overcome spatial limitations while maintaining stringent tolerances. These promising metrics demonstrate that 6.2 mm-pitch modules are highly suitable for the next generation telescopes and the massive multi-object spectroscopic facilities.

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