In October 2023, TMT International Observatory contracted AMOS to develop the Secondary Mirror Support System and Positioner (M2SSP). The M2SSP was identified by TIO as a critical sub-system for which early design would substantially reduce technical, schedule and cost risks to the overall TMT project development plan. In this paper, we present the preliminary design of the M2SSP elaborated by AMOS to comply with the demanding performance requirements imposed by the operational cases and the environment of TMT. The M2SSP is composed of a semi-active mirror support assembly (M2CA) and a positioner (M2POS) that consists of a hexapod with tracking capabilities.
METimage is an advanced multispectral radiometer for weather and climate forecasting developed by Airbus Defence & Space under the auspices of the German Space Administration (DLR) for the EUMETSAT Polar System-Second Generation (EPS-SG). The instrument is equipped with a continuously rotating scan mirror with a 1.7s period followed by a static telescope. The scan mirror permits an extended Earth view of 108° per revolution and regular views to on-board calibration sources. A derotator assembly, which is half-speed synchronised with the scanner, is inserted in the optical beam after the telescope to compensate the image rotation in the focal plane. The derotator optical arrangement is a five-mirror concept that minimises the polarisation sensitivity. The derotator design is constrained by optical performance, mass and compactness, which led to the selection of a full silicon carbide (SiC) concept. The stringent alignment requirements of the derotator optics lead to an excellent pointing accuracy, confirmed by the measurements performed with a dedicated OGSE. The measured wavefront error of the system is very small, thanks to fine polishing of the five optics. In this paper, we will present the overall design of the derotator, discuss the manufacturing of the key SiC elements and present the results of the FM1 test campaign.
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.
METimage is an advanced multispectral radiometer for weather and climate forecasting developed by Airbus Defence & Space under the auspices of the German Space Administration (DLR) for the EUMETSAT Polar System –Second Generation (EPS-SG). The instrument is equipped with a continuously rotating scan mirror with a 1.7s period followed by a static telescope. The scan mirror permits an extended Earth view of 108° per revolution and regular views to on-board calibration sources. A derotator assembly, which is half-speed synchronised with the scanner, is inserted in the optical beam after the telescope to compensate the image rotation in the focal plane. The derotator optical arrangement is a fivemirror concept that minimises the polarisation sensitivity. The derotator design is constrained by optical performance, mass and compactness, which led to the selection of a full silicon carbide (SiC) concept. This paper describes the preliminary design and verification approach of the derotator optics.
The deployment of the Magdalena Ridge Observatory Interferometer has resumed in 2016. AMOS, in charge of the development of the unit telescopes, has completed the installation of the first telescope on the Ridge. The compactness of the system allows for a fast installation, as only the optics and their supports need to be transported in separate crates. The installation has been followed by the alignment procedure combining metrological and optical measurement techniques and aiming at optimizing the pupil stability and image quality. Finally, the performance of the telescope has been evaluated on the sky as part of the site acceptance.
The Javalambre Survey Telescope (JST/T250) is a wide-field 2.6 m telescope ideal for carrying out large sky photometric surveys from the Javalambre Astrophysical Observatory in Teruel, Spain. The most immediate goal of JST is to perform J-PAS, a survey of several thousands square degrees of the Northern sky in 59 optical bands, 54 of them narrow (∼ 145 Å FWHM) and contiguous. J-PAS will provide a low resolution photo-spectrum for every pixel of the sky, hence promising crucial breakthroughs in Cosmology and Astrophysics. J-PAS will be conducted with JPCam, a camera with a mosaic of 14 CCDs of 9.2k × 9.2k pix, more than 1200 Mpix and an effective FoV of 4.3 deg2 . Before JPCam is on telescope, the project will work in 2018 with an interim camera, JPAS-Pathfinder, with a reduced FoV of ∼ 0.6 × 0.6 deg2 to perform commissioning and the first JST science. This paper presents the current status and performance of the JST telescope, describing the commissioning and first science of the JPAS-Pathfinder at JST.
AMOS has recently completed the alignment campaign of the 2.6m telescope for the Observatorio Astrofisico de Javalambre (OAJ). AMOS developed an innovative alignment technique for wide field-of-view telescopes that has been successfully implemented on the OAJ 2.6m telescope with the active support of the team of CEFCA (Centro de Estudios de Física del Cosmos de Aragón). The alignment relies on two fundamental techniques: (1) the wavefront-curvature sensing (WCS) for the evaluation of the telescope aberrations at arbitrary locations in the focal plane, and (2) the comafree point method for the adjustment of the position of the secondary mirror (M2) and of the focal plane (FP). The alignment campaign unfolds in three steps: (a) analysis of the repeatability of the WCS measurements, (b) assessment of the sensitivity of telescope wavefront error to M2 and FP position adjustments, and (c) optical alignment of the telescope. At the end of the campaign, seeing-limited performances are demonstrated in the complete focal plane. With the help of CEFCA team, the image quality of the telescope are investigated with a lucky-imaging method. Image sizes of less than 0.3 arcsec FWHM are obtained, and this excellent image quality is observed over the complete focal plane.
AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation (Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT). The telescope has Ritchey-Chrétien optical configuration with one axial and two side Cassegrain ports. The meniscus primary mirror is active and it is supported by pneumatic actuators. The azimuth axis system is equipped with hydrostatic bearing. After successful factory acceptance at AMOS SA, the telescope has been dismounted, packed, transported, and remounted on site. This paper provides the final performances (i.e. image quality, pointing and tracking) measured during sky tests at Devasthal Observatory.
In this paper, we present the work on characterization of friction in the 3.6 m Devasthal optical telescope axes. The telescope azimuth axis is supported on a hydrostatic bearing while the altitude and rotator axes are supported on hydrodynamic bearings. Both altitude and azimuth axes are driven directly by high power BLDC motors and the rotator is driven by BLDC motor via a gearbox. This system is designed by AMOS, Belgium and tuned to achieve a tracking accuracy better than 0.1 arcsec RMS. Friction poses control related problems at such low speeds hence it is important to periodically characterize the behaviour at each axes. Compensation is necessary if the friction behaviour changes over the time and starts dominating the overall system response. For identifying friction each axis of telescope is rotated at different constant speeds and speed versus torque maps are generated. The LuGre model for friction is employed and nonlinear optimization is performed to identify the four static parameters of friction. The behaviour of friction for each axis is presented and the results are discussed.
An active optics system is being developed by AMOS for the new 4m-class telescope for the Turkish Eastern Anatolia Observatory (DAG). It consists in (a) an adjustable support for the primary mirror and (b) two hexapods supporting M2 and M3. The M1 axial support consists of 66 pneumatic actuators (for mirror shape corrections) associated with 9 hydraulic actuators that are arranged in three independent circuits so as to fix the axial position of the mirror. Both M1 support and the hexapods are actively controlled during regular telescope operations, either with look-up tables (openloop control) or using optical feedback from a wavefront sensor (closed-loop control).
AMOS S.A. has developed a 2.6 m wide field telescope for the “Observatorio Astrofisico de Javalambre”. The leading edge performance of this telescope has not only required an extensive work of design, analysis and optimization but also a mastered fabrication process and an appropriate AIV plan. The telescope has successfully passed the factory test and is installed at the observatory on the “Pico del Buitre” in Spain. This paper aims to present the philosophy of the test, the results and the current status after installation. AMOS has gained since more than 30 years a huge experience in testing small and large instruments, including optical testing, alignment, mechanical static, dynamic measurements, system identification, etc. It is this combination of various techniques of measurement that produce accurate and reliable results which are a key element of a successful project.
AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation
(Nainital, Devasthal site at 2540 mm altitude) of the 3,6 m Optical Telescope for ARIES (Aryabhatta Research Institute
of Observational Sciences), Nainital (India).
This paper describes the architecture deployed for the whole telescope control. It contains, in others, the Telescope
Control System (TCS), the Active Optic System (AOS) and the Auto Guiding Unit (AGU). The TCS generates the
telescope axes trajectory from the celestial coordinates selected by the operator and drives the main axes. The AOS
generates the force set points for each M1 actuator and the position set point of the M2 hexapod from the data given by a
wave front sensor. The AGU sends the main axes corrections from the movement of the guide star on the guiding CCD.
The modules shall communicate between them to optimize the telescope behavior and with the Observatory Control
System (OCS) for data reporting and synchronization with the instrument.
AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation
(Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT).
The telescope has a Ritchey-Chrétien optical configuration with a Cassegrain focus equipped with one axial port and two
side ports. The meniscus primary mirror is active and is supported by pneumatic actuators. The mount is an Alt-Az type
with for the azimuth axis a 5 m diameter hydrostatic track.
The telescope was completely assembled and tested in AMOS workshop. This step is completed and successful. The
telescope is now ready for shipment to Nainital.
This paper describes the test campaign at sub-system and system level that has taken place to demonstrate that the
telescope satisfies the main system requirements. Besides of the functionality of the telescope, the units interacting with
the image quality or the tracking performance were plenty tested. Some selected tests directly connected to the
performance of the telescope are also looked specifically in this paper.
AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation
(Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT).
The telescope has a Ritchey-Chrétien optical configuration with a Cassegrain focus equipped with one axial port and
two side ports. The primary mirror is a meniscus active mirror. The mount is an Alt-Az type with for the azimuth axis a
5 m diameter hydrostatic track. This paper presents the solution adopted by AMOS to meet the specific requirements for
the azimuth axis. The track is designed to be able to control the positioning of the telescope around the azimuth axis
with an accuracy of 0.05 arc second for all tracking configurations. The challenge came from this tight accuracy with a
mass in rotation weighting 125 tons. The azimuth track was mounted and tested in AMOS workshop; the tests and
performances are also discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.