The Salto demonstrator is a complete 1-m class telescope with a single-conjugated Rayleigh laser guide star adaptive optics (AO) system. The project aims to benchmark robust AO operations for astronomy giving an opportunity to upgrade medium size telescopes (1-4 m diameter) around the world and boost their scientific yield. But it is also a benchmark for optical communications and space debris tracking under mediocre seeing conditions, far worse than astronomical standards. Indeed, the foreseen location of the telescope is at the premises of Redu Space Services in the Belgian countryside. In our contribution, we review the overall design of the AO instrument from the optical definition to the real-time computer implementation. We discuss the integration, the calibration, and operational aspects of the instrument. Finally, we present the successful first on-sky operations, reaching the diffraction limit at 1.55μm under 2-3” seeing.
AMOS with EIE as main subcontractor has recently completed the erection of the 4 m telescope located at the Turkish Eastern Anatolia Observatory (DAG) set up by the Ataturk University Astrophysics Research and Application Centre (ATASAM) of Erzurum. The telescope design is based on a Ritchey-Chrétien configuration with two folded Nasmyth focal planes and a focal length of 56m. The optical train is composed of three mirrors: the primary mirror (M1) with an optical aperture of 4m, a convex secondary mirror (M2), and a large flat folding mirror (M3). Diffraction-limited performances in optical and near infrared spectral bands will be achieved thanks to the combination of active and adaptive optics systems. The active optics system is controlling the shape of the primary mirror by means of 66 axial force actuators and position actively the secondary and tertiary mirrors by means of hexapods. The adaptive optics system will be implemented at one of the two Nasmyth ports. As main contractor, AMOS is in charge of the overall project management, the system engineering, the optical design and the active optics development. As main sub-contractor and partner of AMOS, EIE is in charge of the development of the mount. Following the factory acceptance in Europe, the telescope was dismounted and delivered in early 2021. The activities onsite were carried out according to the assembly, integration and verification plan (AIV plan). In the meantime, the fabrication of the 4 m primary mirror was completed, and the full set of mirrors was forwarded on-site before the end of the year 2021. In this paper is presented a brief description of the design and performances of the telescope followed by the project progress status at the time the optics are being integrated in the telescope for the first time. This includes the review of the mirrors as-built quality and the excepted performances of the telescope mount after alignment and tuning. The path forward final acceptance is explained with the presentation of the optical alignment method and the test carried-out on-sky.
AMOS has recently completed the on-site erection and performance evaluation campaign of the 2.5m telescope that is installed on Mount Abu (India) for the Physical Research Laboratory. The 20-m-focal-length telescope has a Ritchey-Chrétien optical configuration. It is equipped with a primary active mirror; an active positioning of the secondary mirror and a first order adaptive optical system. It operates in the 0.37-4 μm spectral range. The project fulfillment relies on the AMOS multidisciplinary expertise in design; manufacturing and verification of high-accuracy optical; mechanical and opto-mechanical systems. This paper presents the assembly; integration; alignment and verifications carried out on site. The alignment relies on the coma-free point method. The end-to-end telescope performances (image quality; pointing; tracking) are measured on sky using the verification instrument in combination with wavefront-curvature sensing and lucky imaging techniques.
Before the transport of a large telescope on site, it is suitable to perform factory tests to guarantee the optical performances. AMOS SA has been awarded of the contract from the design to on-site installation (in Rajasthan) of the 2.5-m Class Telescope for Physical Research Laboratory. The 20-m-focal-length telescope has a Ritchey-Chrétien optical configuration and provides at Cassegrain location one axial port and two side ports. It is equipped with a primary active mirror and a first order adaptive optical system. It operates in the 0.37-4 μm spectral range. The project fulfillment relies on the AMOS multidisciplinary expertise in design and manufacturing of high-accuracy optical, mechanical and opto-mechanical systems. This paper presents the test results carried out at AMOS factory to assess the telescope performances (e.g. active optic control loop, pointing, tracking). It relies on extensive tests on the mount control, and the optical and mechanical sub-systems before assembly.
AMOS S.A. is in charge of the development and installation of a 2.5 m telescope for Physical Research Laboratory (PRL) of India. It is a 20 m focal length Ritchey Chretien Cassegrain configuration equipped with active optics.
AMOS has acquired in more than 30 years a large experience in design, analysis, fabrication and commissioning of 2 to 4 m-class telescopes. Strong of this experience, the multidisciplinary integrated team of the project was able to design the Mt ABU 2.5-m telescope in one year with a great mastering of the technologies and sub-systems development which are used. This is the key point for the risk management of the project.
In this paper is presented the overall design of the telescope. This includes the optical design, the opto-mechanical design of the mirror supports and, in particular the active primary mirror support, the mount design and the control system for which AMOS has developed a main axes servo control based on industrial programmable logic controller (PLC). The closed loops sensing devices (wavefront sensor and guider) and their associated control systems are also presented. The Assembly, Integration and Verification (AIV) activities are finally discussed.
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