MORFEO is a post-focal adaptive optics module that forms part of the first light instrument suite for the Extreme Large Telescope (ELT). The project is now in the Final Design Phase. In this paper, we report the status of the project.
MORFEO (Multi-conjugate adaptive Optics Relay For ELT Observations), formerly known as MAORY, is the Multi-Conjugated Adaptive Optics (MCAO) module for the Extremely Large Telescope (ELT). MORFEO is designed to feed the near-infrared camera MICADO (with the capability to feed a second port dedicated to a future instrument) with both MCAO and Single-Conjugated AO (SCAO) operation modes. The optical configuration provides a one-to-one imaging of the telescope focal surface on the two ports and it is equipped with two post-focal deformable mirrors together with the 6 Laser Guide Star (LGS) and 3 Natural Guide Star (NGS) channels for wavefront sensing and tomographic reconstruction. We present here the Final Design of the MORFEO optical configuration and the expected performances.
MORFEO is the multi-conjugate adaptive optics system of the Extremely Large Telescope (ELT). A key component of MORFEO is the the natural guide star (NGS) wavefront sensor (WFS) module that aims to implement the hardware and functionalities required to sense the lower orders of the atmospheric turbulence, integrating the tomographic reconstruction of the wavefront aberrations achieved in collaboration with the six laser guide stars (LGS) WFS. Currently, the final design of the NGS WFS sub-system is ongoing. In this paper we aim to update on the key aspects of the ongoing work regarding the optical and mechanical design and analyses, the electrical components selection and layout.
To facilitate easy prediction and estimation of adaptive optics performance, we have created a fast algorithm named TipTop. This algorithm generates the expected AO point spread function (PSF) for any existing AO observing mode (SCAO, LTAO, MCAO, GLAO) and any set of atmospheric conditions. Developed in Python, TipTop is based on an analytical approach, with simulations performed in the Fourier domain, enabling very fast computation times (less than a second per PSF) and efficient exploration of the extensive parameter space. TipTop can be used for several applications, from assisting in the observation preparation with the exposure time calculator (ETC), to providing PSF models for post-processing. TipTop can also be used to help users in selecting the best NGSs asterism and optimizing their observation. Over the past years, the code has been intensively tested against other simulation tools, showing very good agreements. TipTop is also currently deployed for VLT instruments, as proof of concepts in preparation of the ELT. The code is available here: https://tiptop.readthedocs.io/en/main/, and we encourage all future observers of the ELT to test it and provide feedback.
In the upcoming future the Adaptive Optics group of the Arcetri Observatory aims to integrate and operate two laboratory R&D facilities dedicated to explore new technologies for the operation of the next generation of 40m-class telescopes. In a nutshell they are aimed to: 1) to investigate the benefits of a dual-stage AO system for planet finding instruments (like ELT/PCS) and 2) the identification of a suitable sensor for the control of the piston error on the ELT and GMT. The participation of the Arcetri AO group to the STILES project granted the necessary funding and the perfect time frame to procure the key components required to implement these two facilities. In this paper we will introduce the two R&D facilities, detailing their layout in the laboratory and addressing the specific test cases they will be able to mimic for (e.g. sources, atmospheric conditions, telescope degrees-of-freedom, . . . ). We will then focus on the design of 2 key components of the benches: the custom-made segmented mirror for the AoPetalometer bench and the pyramid wavefront sensors for the AoCascading bench.
Morfeo (Multi-conjugate adaptive Optics Relay For ELT Observations) is an adaptive optics module able to compensate the wavefront disturbances affective the scientific observation. It will be installed on the straight-through port of the telescope Nasmyth platform to serve the first-light instrument MICADO and with the provision for a future second instrument. The module underwent the Preliminary Design Review in 2021 and is expected to be commissioned in 2029. In this paper we present a synthesis of the System Engineering approach adopted to manage the development of the instrument assessing the criticalities of phase B (preliminary design) and preliminary phase C (final design). We will discuss the evolution of the system engineering approach, identifying within the MBSE framework the evolution of the various modelling artefacts. towards the requirements. We will detail the criticalities of the system engineering with a particular focus onto the management of the interfaces between subsystems and external systems (Telescope, other instruments…).
Natural Guide Star (NGS) wavefront sensors (WFS) play a crucial role in multi-conjugate adaptive optics systems by detecting low-order aberrations that laser guide stars cannot measure. In the framework of MAVIS, we plan to use the light from three NGSs to correct the tip-tilt and low-order errors of the wavefront. In this work, we conduct the analysis of the distortions caused by mid-spatial frequency figure errors of the optical surfaces in the NGS WFS channel of the adaptive optics module of MAVIS. These distortions, stemming from component imperfections, can significantly impact wavefront measurements and, consequently, the plate scale in the image plane of the entire instrument. We analyse their influence on the plate scale variations during tracking. Our study quantifies the effect, shedding light on the impact of non-common path distortions between the NGS WFS and the scientific instruments on plate scale variations, ultimately contributing to optimising the MAVIS performance.
Multiconjugate adaptive Optic Relay For ELT Observations (MORFEO, formerly known as MAORY) is the multiconjugate adaptive optics system of the ELT, providing a diffraction limited correction over a 60" field to the near infrared spectroimager MICADO; it recently completed the preliminary design phase. MORFEO's tomographic sensing is based on 12 WaveFront Sensors (WFS) working with 6 Laser Guide Stars (LGS) and 3 Natural Guide Star (NGS) and the wavefront correction is realized through the ELT's adaptive M4 and up to 2 post-focal deformable mirrors. Under median conditions, MORFEO will provide about 35% SR in K band with a 50% sky coverage at the galactic pole, and 55% SR in optimal conditions with a SR variation of ≤ 10% over a 60" corrected field. In this work we brie y summarize the key aspects of the AO system, focusing on the analysis that motivates the main design choices for wavefront sensors, deformable mirrors, real-time control and the many auxiliary loops envisaged to maintain an optimal and stable correction during the observation.
The Multiconjugate adaptive Optic Relay For ELT Observations (MORFEO, formerly known as MAORY) is the adaptive optics (AO) module for the Extremely Large Telescope (ELT) aimed at providing a 1 arcmin corrected field to the Multi-AO Imaging CamerA for Deep Observations (MICADO) and to a future client instrument. It should provide resolution close to the diffraction limit on a large portion of the sky and in a wide range of atmospheric conditions. Its ability to provide a flat wavefront must face the known aspect of the atmospheric turbulence and telescope environment, but also the final characteristic of a telescope still to be fully developed and built. In this work we focused on issues related to the segmentation of the telescope pupil (like low wind effect, residual phasing error at handover and control related issues), that could limit the system performance. MORFEO currently does not foresee a dedicated sensor to measure the phase step between adjacent mirror segments: in this work we study the possibility to use the low order wavefront sensors designed to sense and correct tip-tilt and focus as phasing sensors thanks to the linearized focal-plane technique (LIFT).
Laser Guide Star (LGS) Shack-Hartmann (SH) wavefront sensors for next generation Extremely Large Telescopes (ELTs) require low-noise, large format (∼1Mpx), fast detectors to match the need for a large number of subapertures and a good sampling of the very elongated spots. One path envisaged to fulfill this need has been the adoption of CMOS detectors with a rolling shutter read-out scheme, that allows low read-out noise and fast readout time at the cost of image distortion due to the detector rows exposed in different moments. In this work we analyze the impact of the rolling shutter read-out scheme when used for LGS SH wavefront sensing of the Multiconjugate adaptive Optic Relay For ELT Observations (MORFEO, formerly known as MAORY) for ESO ELT; in particular, we focus on the impact on the adaptive optics correction of the distortion-induced aberrations created by the rolling exposure in the case of fast varying aberrations, like the ones coming from the LGS tilt jitter due to the up-link propagation of laser beams. We show that the LGS jitter-induced aberration for MORFEO can be as large as 100nm rms and we discuss possible mitigation strategies.
MORFEO (formerly known as MAORY) is a post-focal adaptive optics module that forms part of the first light instrument suite for the Extreme Large Telescope (ELT). The project passed the Preliminary Design Review in two stages in April and July 2021 and is now entering the Final Design Phase. In this paper we report the status of the project.
MORFEO/MAORY is the post-focal adaptive optics instrument of the ELT. It is designed to provide the 53×53 arcsec field of view of MICADO with MCAO correction based on split-tomography, where the Low-Order modes are sensed by three NGS-based WFS. To maximize the sky-coverage the LO-WFS are 2×2 subapertures Shack- Hartmann sensors working in the H band, making use of the FREDA detectors. MAORY also implements 3 dedicated NGS-based truth sensors to measure at slow rate the true higher order atmospheric aberrations and to de-trend the LGS WFS measurements. These WFS work with the visible light of the NGS to feed a 10 × 10 SH sensor that makes use of the ALICE detector. Each unit of LOR WFS is provided with a couple of orthogonal linear stages to allow for the NGS acquisition in a 80 arcsec radius. The 3 LOR WFS are arranged at 120° geometry on a common support structure that rigidly connects them to MICADO and its rotator.
In this paper we present the status of the LOR WFS Module at the output of the MORFEO preliminary design review. We focus on the optomechanical arrangement of the subsystem highlighting the design choices and the analyses we carried out to verify its compliance to the requirements.
A new era of ground-based observations, either in the infrared with the next-generation of 25-40m extremely large telescopes or in the visible with the 8m Very Large Telescope, is going to be assisted by multi-conjugate adaptive optics (MCAO) to restore the unprecedented resolutions potentially available for these systems in absence of atmospheric turbulence. Astrometry is one of the main science drivers, as MCAO can provide good quality and uniform correction over wide field of views (∼ 1 arcmin) and offer a large number of reference sources with high image quality. The requirements have been set to very high precisions on the differential astrometry (e.g. 50μas for MICADO/MORFEO - formerly known as MAORY - at the Extremely Large Telescope) and an accurate analysis of the astrometric error budget is needed. In this context, we present an analysis of the impact of MCAO atmospheric tip-tilt residuals on relative astrometry. We focus on the effects of the scientific integration time on tip-tilt residuals, that we model through the temporal transfer function of the exposure. We define intraand inter-exposure tip-tilt residuals that we use in the estimation of the centroiding error and the differential tilt jitter error within the astrometric error budget. As a case study, we apply our results in the context of the MORFEO astrometric error budget.
Laser guide star (LGS) Shack–Hartmann (SH) wavefront sensors for next-generation Extremely Large Telescopes (ELTs) require low-noise, large format (∼1 Mpx), fast detectors to match the need for a large number of subapertures and a good sampling of the very elongated spots. One path envisaged to fulfill this need has been the adoption of complementary metal metal-oxide semiconductor detectors with a rolling shutter read-out scheme that allows low read-out noise and fast readout time at the cost of image distortion due to the detector rows exposed in different moments. Here, we analyze the impact of the rolling shutter read-out scheme when used for LGS SH wavefront sensing; in particular, we focus on the impact on the adaptive optics (AO) correction of the distortion-induced aberrations created by the rolling exposure in the case of fast varying aberrations, like the ones coming from the LGS tilt jitter due to the up-link propagation of laser beams. We show that the LGS jitter-induced aberration for an ELT can be as large as 100-nm root-mean-square, a significant term in the wavefront error budget of a typical AO system on an ELT, and we discuss possible mitigation strategies.
The Adaptive Optics (AO) performance significantly depends on the available Natural Guide Stars (NGSs) and a wide range of atmospheric conditions (seeing, Cn2, windspeed, . . . ). In order to be able to easily predict the AO performance, we have developed a fast algorithm - called TIPTOP - producing the expected AO Point Spread Function (PSF) for any of the existing AO observing modes (SCAO, LTAO, MCAO, GLAO), and any atmospheric conditions. This TIPTOP tool takes its roots in an analytical approach, where the simulations are done in the Fourier domain. This allows to reach a very fast computation time (few seconds per PSF), and efficiently explore the wide parameter space. TIPTOP has been developed in Python, taking advantage of previous work developed in different languages, and unifying them in a single framework. The TIPTOP app is available on GitHub at: https://github.com/FabioRossiArcetri/TIPTOP, and will serve as one of the bricks for the ELT Exposure Time Calculator.
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.