JSC LZOS has been using diffraction optical elements (DOE) or Computer Generated Holograms (CGH) for many years to test the surfaces of large-sized optical mirrors for astronomical and space purposes. They are used for aspherical surface figure testing; testing of aspherical surface vertex position relative to the mirror geometric center, calculation of distortion in interferogram image, mutual adjustment of mirrors in testing scheme, etc. Thus, CGH have become an integral part of the up-to-date testing of large-sized optical mirrors and optical systems aspherical surfaces.
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.
EUCLID is an optical/near-infrared survey mission to be launched towards the L2 Lagrange point. It will aim at studying the dark universe and providing a better understanding of the origin of the accelerating expansion of the universe. Through the use of cosmological sounding, it will investigate the nature of dark energy, dark matter and gravity by tracking their observational signatures on the geometry of the universe and on the cosmic history of large structures formation. The EUCLID PayLoad Module (PLM) consists of a 1.2 m-class telescope and will accommodate two instruments. As a subcontractor of AIRBUS Defence and Space, AMOS is responsible for the manufacturing of all the silicon carbide mirrors of EUCLID PLM except for the primary mirror. In addition, AMOS also produces the 1.3 m test collimator that is used for the on-ground validation of the optical performances of the payload module under operational thermal vacuum conditions. The 1.3m collimator is designed, manufactured, assembled and tested by AMOS. It is based on a Ritchey-Chretien optical configuration, with a f/2 primary mirror and a hyperbolic secondary mirror. The mirrors are made of ZERODUR and polished by AMOS. The high performance of EUCLID PLM calls for not less demanding requirements for the test collimator, in terms of image quality, thermal stability, line of sight stability under micro-vibration, etc. Here after are presented at first the design and the strategies elaborated to cope with the stringent requirements. Then, the manufacturing and metrology of the mirrors are reported. Finally, the Assembly, Integration and Verification by test (AIV) are discussed.
This paper describes the technology of production and testing of mirrors for DAG Telescope (Doğu Anadolu Gözlemevi) produced by Belgium Company AMOS. JSC LZOS fulfils works on production and testing of three mirrors: primary concave hyperbolic mirror of diameter 4 m, secondary convex hyperbolic mirror – 764 mm and tertiary elliptical mirror with flat working surface with dimensions 890х650 mm. The primary mirror is produced from Zerodur, while the secondary and the tertiary ones – from Astrositall. Some auxiliary elements, containers and handling tools, etc. are also produced at JSC LZOS. Special aspects of mirrors machining and testing are also reflected in this article.
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 Unit Telescope (UT) for the Magdalena Ridge Observatory (MROI) is composed of four major hardware components: The Unit Telescope Mount (UTM), Enclosure, Optics and the Fast Tip Tilt System (FTTS). Integration of the UT started in 2016 when the UTM arrived and its Assembly, Integration and Verification activities began. Critical activities included: installation at the Maintenance Facility, integration and alignment of the Optics and Wave Front Sensor (WFS) and finally the complete optical alignment. End-to-end UTM Site Acceptance Tests (SAT) were performed. Subsequent activities included receiving and integrating the FTTS. With the arrival and assembly of the Enclosure, the last component of the UT was ready for integration on a dedicated concrete pier. Specialized equipment will be used for the final integration of the UT, and for transportation to its final location on the array where SAT for the UT will take place.
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.
AMOS with EIE as a main subcontractor, was awarded a contract in November 2014 for the design, manufacturing and installation of a 4m-class telescope for the Turkish Eastern Anatolia Observatory (DAG) situated at 3170 m above the sea level in Palandöken mountains. The telescope is based on a Ritchey-Chretien configuration with two folded Nasmyth focal planes and a focal length of 56m.
Diffraction-limited performances will be reached thanks to the combination of the active optics system and the adaptive optics system that will be implemented on one of the Nasmyth ports. The active optics system aims at controlling the shape of the primary mirror by means of 66 axial force actuators and positioning actively the secondary and tertiary mirrors by means of hexapods.
More than 30 years of experience in testing instruments and telescopes, including optical testing, alignment, metrology, mechanical static and dynamic measurements, system identification, etc. allow to implement an adequate verification strategy combining component level verifications with factory and site test in the most efficient and reliable manner.
As a main contractor, AMOS is in charge of the overall project management, the system engineering, the optical design and the active optics development. As a main sub-contractor and partner of AMOS, EIE is in charge of the development of the mount. The factory test therefore takes place in EIE premises.
In this paper is shortly presented the overall design of the telescope with a review of the specification, the optical design and a description of the major sub-systems, including the optics. The assembly, integration et test plan is outlined. The assembly sequence and the tests of the active optics and the mount are discussed. Finally, the site integration and tests are explained. The process to assess the image quality of the telescope and the verification instrument developed for this purpose by AMOS are presented.
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.
EUCLID is an optical/near-infrared survey mission to be launched towards the L2 Lagrange point. It will aim at studying the dark universe and providing a better understanding of the origin of the accelerating expansion of the universe. Through the use of cosmological sounding, it will investigate the nature of dark energy, dark matter and gravity by tracking their observational signatures on the geometry of the universe and on the cosmic history of large structures formation. The EUCLID PayLoad Module (PLM) consists of a 1.2 m-class telescope and will accommodate two instruments. As a subcontractor of AIRBUS Defence and Space, AMOS is responsible for the manufacturing of all the silicon carbide mirrors of EUCLID PLM except for the primary mirror. In addition, AMOS also produces the 1.3 m test collimator that is used for the on-ground validation of the optical performances of the payload module under operational thermal vacuum conditions. The 1.3m collimator is designed, manufactured, assembled and tested by AMOS. It is based on a Ritchey-Chretien optical configuration, with a f/2 primary mirror and a hyperbolic secondary mirror. The mirrors are made of ZERODUR® and polished by AMOS. The high performance of EUCLID PLM calls for not less demanding requirements for the test collimator, in terms of image quality, thermal stability, line of sight stability under micro-vibration, etc. Here after are presented at first the design and the strategies elaborated to cope with the stringent requirements. Then, the manufacturing and metrology of the mirrors are reported. Finally, the Assembly, Integration and Verification by test (AIV) are discussed.
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.
KEYWORDS: Telescopes, Control systems, Computer programming, Optical instrument design, Active optics, Observatories, Finite element methods, Telecommunications, Error analysis, Head
Dogu Anatolu Gözlemevi (DAG-Eastern Anatolia Observatory) Project is a 4m class optical, near-infrared Telescope and suitable enclosure which will be located at an altitude of ~3.170m in Erzurum, Turkey. The DAG telescope is a project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope - ATASAM. The Project is being developed by the Belgian company AMOS (project leader), which is also the optics supplier and EIE GROUP, the Telescope Main Structure supplier and responsible for the final site integration. The design of the Telescope Main Structure fits in the EIE TBO Program which aims at developing a Dome/Telescope systemic optimization process for both performances and competitive costs based on previous project commitments like NTT, VLT, VST and ASTRI. The optical Configuration of the DAG Telescope is a Ritchey-Chretien with two Nasmyth foci and a 4m primary thin mirror controlled in shape and position by an Active Optic System. The main characteristics of the Telescope Main Structure are an Altitude-Azimuth light and rigid structure system with Direct Drive Systems for both axis, AZ Hydrostatic Bearing System and Altitude standard bearing system; both axes are equipped with Tape Encoder System. An innovative Control System characterizes the telescope performance.
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).
EUCLID is an optical/near-infrared survey mission to be launched in 2020 towards the L2 Lagrange point. It will aim at studying the dark universe and providing a better understanding of the origin of the accelerating expansion of the universe. Through the use of cosmological sounding, it will investigate the nature of dark energy, dark matter and gravity by tracking their observational signatures on the geometry of the universe and on the cosmic history of large structures formation.
The EUCLID payload module (PLM) consists of a 1.2 m-class telescope and will accommodate two instruments.
As a subcontractor of AIRBUS Defence and Space, AMOS is responsible for the manufacturing of the secondary and the third mirrors of the telescope as well as for the flat folding mirror set within the focal plane arrangement of EUCLID telescope, which incorporates dedicated filtering functions. AMOS produces in addition the 1.3 m-class test collimator for the on-ground validation of the EUCLID instrument.
In the framework of the design and manufacturing of a wide-field 2.5m telescope for the Observatorio Astrofisica de Javalambre (OAJ), AMOS has developed a novel wavefront sensing system that allows for real time correction of the alignment of the telescope without perturbing the acquisition of science images. The system is based on the wavefront curvature sensing (WCS) technique in which two out-of-focus images of a star are used for reconstructing the telescope wavefront error. Any deviations from the nominal wavefront error that is obtained after telescope final alignment are tracked and corrective actions can be implemented so as to optimize the telescope optical quality. The wavefront reconstruction technique and the associated corrections of the telescope alignment have been modelled and analyzed so as to validate the proposed approach before implementation in the telescope. To this aim, a bespoke coupled Zemax-Matlab model has been developed by AMOS. The model incorporates the algorithm for the telescope wavefront error reconstruction from out-of-focus images and computation of the alignment corrections in the telescope model. The justification of the wavefront sensing approach, its robustness against several sources of errors, as well as the selection of the appropriate equipment for its implementation in the telescope are discussed on the basis of this combined model.
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 S.A. is in charge of the development of the telescopes for the "Observatorio Astrofisico de Javalambre" in Spain
where a 2.6 m wide field telescope is complemented by an 80 cm telescope. This paper focuses on the 2.6 m telescope
Javalambre Survey Telescope (JST): it is combining a large collecting surface with a wide field of view for reaching a
vast portion of the sky, which is the most relevant parameter for surveys, while ensuring an optical image quality
compatible with the site seeing and a suitable depth in the sky sighting.
The major difficulty consists in maintaining the image quality over a 500 mm focal plane. A good design is the result of
a thorough multidisciplinary optimization process where the fabrication constraints are a major driving parameter. The
complexity of the system led to elaborate innovative solutions for the closed loop control of both image quality and
tracking features.
The design and the methodology of working are presented in details. The optics fabrication, the integration and
acceptance tests are also reviewed.
The Observatorio Astrofsico de Javalambre in Spain is a new astronomical facility particularly conceived for
carrying out large sky surveys with two unprecedented telescopes of unusually large elds of view: the JST/T250,
a 2.55m telescope of 3deg eld of view, and the JAST/T80, an 83cm telescope of 2deg eld of view. The
most immediate objective of the two telescopes for the next years is carrying out two unique photometric
surveys of several thousands square degrees, J-PAS and J-PLUS, each of them with a wide range of scientic
applications, like e.g. large structure cosmology and Dark Energy, galaxy evolution, supernovae, Milky Way
structure, exoplanets, among many others. To do that, JST and JAST will be equipped with panoramic cameras
under development within the J-PAS collaboration, JPCam and T80Cam respectively, which make use of large
format (~10k×10k) CCDs covering the entire focal plane. This paper describes the current status and expected
schedule of the overall project, the main characteristics of the telescopes, their cameras, the technical requirements
of the two planned surveys, as well as the general operation strategy of the observatory.
AMOS is in charge of the development of the unit telescopes for the MRO interferometer. This paper depicts the
progress of the project and presents the results of the factory acceptance tests that were performed at AMOS facilities.
Those tests are the earliest verifications of the telescope performance. AMOS has now extensive 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.
AMOS is in charge of the development of the unit telescopes of the MRO interferometer. Beyond the image quality and
the tracking performance, the interferometry necessitates maintaining the optical pathlength between two telescopes
sufficiently stable during observation. This paper depicts the detailed design of the telescopes and how it suits to the high
end requirements of the system. The distinctive features of the elevation over elevation configuration are also discussed.
Bertrand Koehler, Max Kraus, Jean-Michel Moresmau, Krister Wirenstrand, Michel Duchateau, Philippe Duhoux, Robert Karban, Carlo Flebus, E. Gabriel, Olivier Pirnay
The Very Large Telescope Interferometer (VLTI) that currently combines the four VLT 8.2-m Unit Telescopes (UTs) is now being equipped with its dedicated array of Auxiliary Telescopes (ATs). This array includes four 1.8-m telescopes which can be relocated on thirty observing stations distributed on the top of the Paranal Observatory. This array, albeit less sensitive than the array of UTs, is a key element for the scientific operation of the VLTI.
After more than five years of design, development, manufacturing and extensive testing in Europe by the company AMOS (Belgium), the first AT arrived on Paranal in October 2003 where it was re-assembled in two months. This was followed by the final testing on the sky, the so-called 'commissioning', that took place in January and February 2004.
This paper describes the recent activities from the delivery of AT1 in Europe up to its commissioning at Paranal. It presents a few results from the commissioning and reports the achieved performance. The status of the other ATs is also briefly described.
As part of the Very Large Telescope Interferometer (VLTI), ESO signed in June 1998 a contract with AMOS S.A. covering the design, manufacturing and testing of the Auxiliary Telescope System (ATS), including three movable auxiliary telescopes (AT) and the associated site equipment. The project entered into manufacturing phase in mid-1999.
As a prime contractor, AMOS S.A. had to deliver complete and fully operational telescopes ready to plug on any of the thirty stations of the VLTI sub-array. This work required an overall system level approach involving a multi-skilled team.
This paper depicts the progress status and presents the results of the main tests -- except optical testing -- performed on the telescopes in AMOS facilities. Those tests are the earliest verification of high-level requirement specifications such as optical path length (OPL) stability, pointing error, main axis dynamic response, performed on the telescope fully integrated.
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