arXiv subjects

C. Del Vecchio

Publications and source records attributed to C. Del Vecchio.

3 recordsLinked to original sources

arXiv2026

Progress of the design of the 12-m optical, Wide-field Spectroscopic Telescope (WST)

The Wide-Field Spectroscopic Telescope (WST) is a 12-m class, Alt-Az optical telescope providing two simultaneous foci, 2 degrees and 3 by 3 arc minutes respectively, for Multi-Object Spectroscopy (MOS) and Integral Field Spectroscopy (IFS) at visible wavelengths. Within the framework of the Horizon Programme, the project has been approved for phase A funding by the EC in 2024 and is currently undergoing intensive development. The optical design relies on a corrected Cassegrain solution feeding multi-object spectrographs through fibres, while the central area of the field is propagated to a gravity-stable Integral Field Station housing an array of spectrographs. We report progress of the design, of the functional and physical definitions of key subsystems, and of the design of high-performance coatings of the telescope optics. The telescope would be located near ESO Paranal - Armazones observatory and protected by a VLT-like enclosure. With a view to minimising risks, from capital investment to operations, designs build extensively on VLT and ELT solutions. Owing to the optical configuration, the telescope can be wavefront-controlled at both foci, with little if any crosstalk between MOS and IFS controls. The optical path is constrained to provide natural guide star, ground-layer adaptive correction at the IFS field, within existing technology. Finally, from its earliest stage of development the system is being scrutinized for its properties in relation to sustainability.

astro-ph.IM↗

arXiv2024

Membrane Space Telescope: Active Surface Control with Radiative Adaptive Optics

Sensitivity and resolution of space telescopes are directly related to the size of the primary mirror. Enabling such future extremely large space telescopes or even arrays of those will require to drastically reduce the areal weight of the mirror system. Utilizing a thin parabolic polymeric membrane as primary mirror offers the prospect of very low weight and the flexible nature of those membranes allows compactly store them upon launch. Upon deployment the structure is unfolded and the mirror shape restored. Being an extremely thin structure, an active shape correction is required. Utilizing a thermal control of the surface via radiative coupling, localized shape changes are imprinted into the membrane telescope. In this paper we present the modelling and experimental test of the radiative adaptive optics. A detailed modeling of the influence function of the radiative shaping onto the membrane mirror has been carried out. Experimentally we have been radiatively actuated the shape of a prototype mirror in closed loop with a wavefront sensor and proven that we can control the mirrors surface figure to a ~15nm RMS precision.

astro-ph.IM↗

arXiv2021

A prototype of a large tunable Fabry-Perot interferometer for solar spectroscopy

Large Fabry-Perot Interferometers are used in a variety of astronomical instrumentation, including spectro-polarimeters for 4-meter class solar telescopes. In this work we comprehensively characterize the cavity of a prototype 150 mm Fabry-Perot interferometer, sporting a novel, fully symmetric design. Of note, we define a new method to properly assess the gravity effects on the interferometer's cavity when the system is used in either the vertical or horizontal configuration, both typical of solar observations. We show that the symmetric design very effectively limits the combined effects of pre-load and gravity forces to only a few nm over a 120 mm diameter illuminated surface, with gravity contributing about 2 nm peak-to-valley (0.3 nm rms) in either configuration. We confirm a variation of the tilt between the plates of the interferometer during the spectral scan, which can be mitigated with appropriate corrections to the spacing commands. Finally, we show that the dynamical response of the new system fully satisfies typical operational scenarios. We conclude that large, fully symmetric Fabry-Perot interferometers can be safely used within solar instrumentation in both, horizontal and vertical position, with the latter better suited to limiting the overall volume occupied by such an instrument.

astro-ph.IM↗