arXiv subjects

Aaron Omadutt

Publications and source records attributed to Aaron Omadutt.

5 recordsLinked to original sources

arXiv2026

Exploration of small footprint stick-slip piezoelectric actuators for use in the FLEX fibre positioner system for the Wide-field Spectroscopic Telescope (WST)

This work presents a novel stick-slip piezoelectric actuator for the FLEX fibre positioner, addressing the challenge of reducing footprint while maintaining precision in next-generation multi-object spectroscopic instruments such as the Wide-field Spectroscopic Telescope (WST). The actuator combines compact geometry (3.2 mm diameter, sub 70 mm length) with high-resolution incremental motion, low power consumption, and high reliability. Three actuators can be integrated into a sub 7 mm diameter circle, enabling a simplified, single-plane assembly. This design offers a promising solution for miniaturized, accurate fibre positioning in wide-field spectroscopic applications.

astro-ph.IM↗

arXiv2026

WST, the wide-field spectroscopic telescope: progress on the design of the instruments

WST, the Wide-field Spectroscopic Telescope is a proposed new facility that will provide a transformational gain in spectroscopic survey capability over existing facilities. The WST is a 12 metre class telescope equipped with instrumentation to provide simultaneous observations in both multiple-object spectroscopy and integral field spectroscopy modes. This paper will describe the status of the instruments being designed for the WST, the fibre positioner module, the low and high-resolution multiple object spectrographs, the integral field spectrograph, disperser technology, sustainable detector and cryostat technology, and the calibration system. An overview of the overall layout of the instruments within the WST facility will be provided.

astro-ph.IM↗

arXiv2026

High multiplex and precision: the design and development of FLEX, a grid-based fiber positioner with large patrol radius and minimized telecentric error

In next-generation spectroscopic facilities, high-multiplex fiber positioning systems must operate within highly constrained focal surfaces, such as the Wide-Field Spectroscopic Telescope (WST) requiring 30,000+ fibers across a 1.4-meter surface. The Fiber Location EXtender (FLEX) positioner meets these constraints by improving fiber patrol radii while minimizing telecentric error and positioner spacing for dense clustering and high Multi-Object Spectrograph (MOS) multiplexing. The patented FLEX concept utilizes a superelastic nickel-titanium alloy (Nitinol) inside three concentric, geometrically altered tubes. This construction ensures the tip remains parallel with its base during tilting, while internal routing allows the fiber to run freely along the axis to minimize Focal Ratio Degradation (FRD). Designed for a patrol radius of 2.5x the pitch within the WST architecture, the design delivers a maximum patrol radius up to ~22.5 mm with a telecentric error of less than 0.39 degrees. FLEX utilizes three piezoelectric actuators to provide large radial displacements and precise focus adjustment. To scale this architecture, a modular focal surface layout of 90 identical curvilinear modules has been devised. This layout houses 30,240 positioners across a 2-degree hexagonal field-of-view (FoV), accommodating a central hole for an Integral Field pickoff mirror. Only three support struts are required, obscuring just 0.8% of the FoV while allowing full positioner coverage. One in 16 positioners is allocated for high-resolution spectroscopy, with the remainder split among three low-resolution spectrograph sets; all four sets achieve virtually full coverage of the FoV.

astro-ph.IM↗

arXiv2026

WST -- Wide-field Spectroscopic Telescope: The Next Leap in Wide-field Spectroscopy

The Wide-field Spectroscopic Telescope (WST) is a concept for a dedicated 12-m spectroscopic survey facility designed to address some of the most important questions in astrophysics in the 2040s. The WST will provide unprecedented spectroscopic survey capabilities by operating simultaneously over a 2-degree diameter field of view with 54 low-resolution spectrographs fed by 30,000 fibres, 8-16 high-resolution spectrographs fed by 2,000 fibres, and a large panoramic low-resolution integral-field spectrograph. Supported by Horizon Europe, the concept study has refined the science cases, facility architecture, operations model, sustainability strategy, and technology roadmap. The resulting reference design demonstrates that the WST is both scientifically transformative and technically feasible, while identifying the developments required to mitigate the remaining risks. The WST is designed as an ESO flagship facility for the post-ELT construction era and a key spectroscopic complement to the major imaging, time-domain, and multi-messenger facilities of the coming decades.

astro-ph.IM↗

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↗