MICADO is a cryogenic near infrared Multi-AO Imaging Camera and Spectrometer developed for the first light operations at the ELT. It will operate in a “Standalone” configuration with a Single Conjugate Adaptive Optics module for a nominal period of two years. After this time, the system will be re-arranged in the “MICADO-MORFEO” configuration, being able to switch between the SCAO and a Multi Conjugate Adaptive Optics module in the later phase of the project. The lifetime requirement of minimum ten years, together with other demanding requisites about its availability and reliability triggered a meticulous FMECA analysis mainly focused on developing robust maintenance strategies. In this paper, we outline the assumptions and the boundaries of the MICADO RAM analysis, a collaborative effort involving the Max Planck Institute for the Extraterrestrial Physics, the Laboratoir d’Études Spatiales et d’Instrumentation en Astrophysique and the European Southern Observatory, starting from the input provided by all MICADO partners. We describe how RAM aspects drove some design choices as well as the selection and use of components. We report the preventive and predictive maintenance strategies, which we considered to minimize the risk of instrument downtime in the high cost operational context of the ELT.
REMIR is a NIR camera mounted on the REM telescope at ESO-La Silla Observatory. Soon after its installation in 2003, the REMIR camera went through a series of cryogenics problems, due to the bad functioning of the Leybold cryocooler Polar SC7 and we were forced to change drastically the cryogenics of REMIR, going from cryocooler to LN2, via an ad-hoc modified Continuos Flow Criostat, a cryogenics system developed by ESO. Today, the availability of new generation small cryocoolers, in our case the Sunpower CryoTel GT AVC, allowed us to change again and come back to the original cryogenics for the REMIR camera. The system has been assembled and intensively tested at ESO and at INAF-OAR premises, then it has been mounted on the REMIR camera and tested at working condition. In this paper we report the details and results of the project.
MICADO is the ELT first light instrument, an imager working at the diffraction limit of the telescope thanks to two adaptive optics (AO) modes: a single conjugate one (SCAO), available at the instrument first light and developed by the MICADO consortium, and a multi conjugate one (MCAO), developed by the MORFEO consortium.
This contribution presents an overview of the SCAO module while MICADO and its SCAO are in the last phase of their final design review. We focus on the SCAO architecture choices and present the final design of the SCAO subsystems: the Green Doughnut structure, the SCAO wavefront sensor, the SCAO calibration unit, the SCAO ICS (i.e. AOCS) and the SCAO RTC. We also present the SCAO global performance in terms of AO correction, obtained from an error budget that includes contributors estimated from AO end-to-end simulations as well as instrumental contributors. Finally, we present the current SCAO subsystems prototyping and the main milestones of the SCAO AIT plan.
MICADO is a first light instrument for the ELT: it will provide diffraction limited imaging, in standard, astrometric, and coronagraphic modes, and long-slit spectroscopy at near-infrared wavelengths, covering a 19” FoV with a 1.5 mas/px sampling, or a 50.5” FoV with a 4.5 mas/px sampling. The challenging scientific goals in terms of sensitivity, resolution, astrometric precision, and contrast at small inner working angles have been translated in technical requirements and flowed down to the sub-systems. Each sub-system shall undergo a verification campaign and demonstrate the required performance before the integration at higher system level. In this paper, we describe the planned strategy for the optomechanical characterization of the Cold Optics, i.e. the three opto-mechanical sub-systems, which represent the backbone of the MICADO Cryostat. Given the demanding requirements applied to the performance of the Cold Optics, a proper support equipment for the correct execution of the tests has been designed. Tests will be performed in warm conditions and the most significant will be repeated in a cold environment, representative of the MICADO cryostat.
MICADO, a first light ELT instrument, will provide diffraction limited imaging, astrometry, high contrast imaging, and slit spectroscopy. It will achieve an unprecedented combination of sensitivity and resolution at near-infrared wavelengths using its own SCAO system as well as the LGS-MCAO module MAORY. This contribution describes MICADO at its Final Design Review, explaining how the instrument was developed to fulfil the science and technical requirements, as well as meet the operational and maintenance requirements. Some thoughts about the dramatic difference between ELT and VLT projects are presented, and what this might mean for future instrumentation.
The paper reports an overview of the preliminary optical design for the MICADO Relay Optics (RO) to enable early science observations of the instrument at the Extremely Large Telescope (ELT) with single-conjugate adaptive optics (SCAO). MICADO, the Multi-AO Imaging Camera for Deep Observations, is a first light imager, astrometric camera and spectrograph operating between 0.8 µm and 2.4 µm. The RO are based on a six mirror (6M) optical assembly that relays the telescope focal plane to an accessible position for the MICADO cryostat. The system includes three powered mirrors in a three-mirror-anastigmat configuration and three piston and tip- tilt flat mirrors for the alignment and the beam folding at the interfaces with the ELT and MICADO. This design represents an interesting example of optical performance optimization to achieve high performances optics both for the direct imaging channel and the pupil interface towards MICADO and the SCAO. The RO performances are analyzed and verified at a design level showing the compliance with the requirement specifications and the reliability of the design is assessed with an extended tolerance study and a minimization of the vignetting factor at the MICADO cold stop. The manuscript also contains a demonstration of the optical alignability of a 6M system in terms of pupil and focal plane steering that are essential to cope with the interface tolerances of the next generation of instrument at the foci of the extremely large telescopes.
MICADO is the Multi-AO Imaging Camera for Deep Observations, a first light instrument for the Extremely Large Telescope (ELT). The instrument provides imaging, astrometric, spectroscopic and coronographic observing modes. MICADO will be assisted by a Single-Conjugate Adaptive Optics (SCAO) system and the Multi-conjugate Adaptive Optics RelaY (MAORY). The instrument will provide a narrow (19′′) and a wide (51”) Field of View. MICADO can operate in the so-called stand-alone mode in the absence of MAORY with the SCAO correction alone. Here, we present the opto-mechanical design of the Relay Optics (RO), the optical system relaying the ELT focal plane to an accessible position for MICADO using the SCAO-only stand-alone observing mode. The RO consists of an optical bench made of carbon fiber reinforced plastic (CFRP), an optical assembly made of three flat mirrors with motorized piston-tip-tilt mounts and three additional powered mirrors of up to ~500 mm in diameter, the MICADO calibration assembly, and a cover to protect all opto-mechanical components on top of the bench. A 9-point whiffletree support, combined with a thermal compensation system is implemented for the critical mirrors. The static and the dynamic performance of the MICADO RO are investigated through a detailed Finite Element Model (FEM), the results are combined with a Zernike basis representation of the mirror surface deformations performed in Zemax for assessing the optical performance.
We present an update of the design of the Central Wheel Mechanism (CWM), a subsystem of the MICADO instrument for the Extremely Large Telescope (ELT)1. The CWM consists of a Filter Wheel Mechanism (FWM) with two Filter wheels, the Pupil Wheel Mechanism (PWM) with one Pupil wheel and the Atmospheric Distortion Corrector (ADC). The CWM has a diameter of about 1.5 meter. Challenges in the mechanical design work are focused on fitting all the components in the available design volume and ensuring that the accuracy and repeatability requirements are met. The mechanisms should work in a cryogenic environment for an intended lifetime of 10 years and survive transport and seismic conditions. Additionally the system has to cool and warm-up properly. The most noticeable update since the PDR2 is a self-contained ring assembly of a connected FWM and PWM that is suspended to the MICADO instrument using flexible supports. The arrangement of these supports creates a point of shrinkage at the optical position which is off-axis from the cryostat center. An alignment tool will guarantee a position accuracy within 50 μm for both the ADC as well as the Pupil masks that are mounted after the system is integrated into the instrument. The most sensitive bearings are protected from shock loads by a system that limits their load carrying capability by transferring the excess load to bumpers. These bumpers do not affect the repeatability of the system.
MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument’s capabilities focus on imaging (including astrometric and high contrast) as well as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and making use of the data simulation tool, an outline is presented of what we can expect the instrument to achieve.
MICADO, the Multi-AO-Imaging-Camera and Spectrometer for Deep Observations, is one of the first light instruments for the future 40 m class Extremely Large Telescope (ELT). MICADO utilizes the advanced laser guide star multiconjugate adaptive optics system MCAO developed by the MAORY consortium and the jointly developed singleconjugate adaptive optics system (SCAO). We present an overview on the conceptual design of the MICADO Cold Optical Instrument (COI) which comprises the infrared focal plane imager with its 3 x 3 4k2 HgCdTe detector array and a compact cross-dispersing slit spectrometer operating in the spectral range of 0.8 to 2.4 μm. High contrast imaging is enabled via a classical configuration of coronagraph and Lyot stops. The paper summarizes the MICADO COI interchangeable optics, its cryogenic implementation together with the modular opto-mechanical configuration of the cryo-mechanisms and the cryo-vacuum cooling system, which consists of a continuous LN2 flow cryostat.
MICADO is the European ELT first-light imager, working in the near-infrared at the telescope diffraction limit. Provided by MAORY, the ELT first-light adaptive optics module (AO), MCAO will be the primary AO mode of MICADO, driving the design of the instrument. MICADO will also come with a SCAO capability. Developed under MICADO’s responsibility and jointly by MICADO and MAORY, SCAO will be the first AO mode to be tested at the telescope, in a phased approach of the AO integration at the ELT. The MICADO-MAORY SCAO preliminary design review (PDR) will occur in November 2018. We present here different activities and results we have had in the past two years preparing this PDR, covering several fields (opto-mechanics, electronics, real-time and control software, integration and tests, AO simulations and performance, prototyping) and the different SCAO subsystems (pyramid wavefront sensor, calibration unit, real-time computer, dichroic and the so-called Green Doughnut which hosts the SCAO assembly as well as the MAORY MCAO natural guide star wavefront sensors).
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.