After completion of its final-design review last year, it is full steam ahead for the construction of the MOONS instrument - the next generation multi-object spectrograph for the VLT. This remarkable instrument will combine for the first time: the 8 m collecting power of the VLT, 1000 optical fibres with individual robotic positioners and both medium- and high-resolution spectral coverage acreoss the wavelength range 0.65μm - 1.8 μm. Such a facility will allow a veritable host of Galactic, Extragalactic and Cosmological questions to be addressed. In this paper we will report on the current status of the instrument, details of the early testing of key components and the major milestones towards its delivery to the telescope.
The Magdalena Ridge Observatory Interferometer (MROI) has been under development for almost two decades. Initial funding for the facility started before the year 2000 under the Army and then Navy, and continues today through the Air Force Research Laboratory. With a projected total cost of substantially less than $200M, it represents the least expensive way to produce sub-milliarcsecond optical/near-infrared images that the astronomical community could invest in during the modern era, as compared, for instance, to extremely large telescopes or space interferometers. The MROI, when completed, will be comprised of 10 x1.4m diameter telescopes distributed on a Y-shaped array such that it will have access to spatial scales ranging from about 40 milliarcseconds down to less than 0.5 milliarcseconds. While this type of resolution is not unprecedented in the astronomical community, the ability to track fringes on and produce images of complex targets approximately 5 magnitudes fainter than is done today represents a substantial step forward. All this will be accomplished using a variety of approaches detailed in several papers from our team over the years. Together, these two factors, multiple telescopes deployed over very long-baselines coupled with fainter limiting magnitudes, will allow MROI to conduct science on a wide range and statistically meaningful samples of targets. These include pulsating and rapidly rotating stars, mass-loss via accretion and mass-transfer in interacting systems, and the highly-active environments surrounding black holes at the centers of more than 100 external galaxies. This represents a subsample of what is sure to be a tremendous and serendipitous list of science cases as we move ahead into the era of new space telescopes and synoptic surveys. Additional investigations into imaging man-made objects will be undertaken, which are of particular interest to the defense and space-industry communities as more human endeavors are moved into the space environment.
In 2016 the first MROI telescope was delivered and deployed at Magdalena Ridge in the maintenance facility. Having undergone initial check-out and fitting the system with optics and a fast tip-tilt system, we eagerly anticipate installing the telescope enclosure in 2018. The telescope and enclosure will be integrated at the facility and moved to the center of the interferometric array by late summer of 2018 with a demonstration of the performance of an entire beamline from telescope to beam combiner table shortly thereafter. At this point, deploying two more telescopes and demonstrating fringe-tracking, bootstrapping and limiting magnitudes for the facility will prove the full promise of MROI. A complete status update of all subsystems follows in the paper, as well as discussions of potential collaborative initiatives.
We present the design of the HARPS3 software system – a distributed, event-driven control system for robotic operation of the HARPS3 spectrograph at the Isaac Newton Telescope (INT). We also describe our approach to integrating the control software components incrementally at various stages of development, using a simulation framework. HARPS3 will be a high resolution (R = 115, 000) echelle spectrograph operating at wavelengths from 380 nm to 690 nm, with a design based on the successful HARPS and HARPS-N instruments. It is being built as part of the Terra Hunting Experiment (THE) – a planned 10 year radial velocity measurement programme to discover Earth-like exoplanets around Sun-like stars.
The first generation of E-ELT instruments will include an optic-infrared High Resolution Spectrograph, conventionally indicated as EELT-HIRES, which will be capable of providing unique breakthroughs in the fields of exoplanets, star and planet formation, physics and evolution of stars and galaxies, cosmology and fundamental physics. A 2-year long phase A study for EELT-HIRES has just started and will be performed by a consortium composed of institutes and organisations from Brazil, Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden, Switzerland and United Kingdom. In this paper we describe the science goals and the preliminary technical concept for EELT-HIRES which will be developed during the phase A, as well as its planned development and consortium organisation during the study.
We present a description of a new instrument development, HARPS3, planned to be installed on an upgraded and roboticized Isaac Newton Telescope by end-2018. HARPS3 will be a high resolution (R≃115,000) echelle spectrograph with a wavelength range from 380-690 nm. It is being built as part of the Terra Hunting Experiment - a future 10- year radial velocity measurement programme to discover Earth-like exoplanets. The instrument design is based on the successful HARPS spectrograph on the 3.6m ESO telescope and HARPS-N on the TNG telescope. The main changes to the design in HARPS3 will be: a customised fibre adapter at the Cassegrain focus providing a stabilised beam feed and on-sky fibre diameter ≈1:4 arcsec, the implementation of a new continuous ow cryostat to keep the CCD temperature very stable, detailed characterisation of the HARPS3 CCD to map the effective pixel positions and thus provide an improved accuracy wavelength solution, an optimised integrated polarimeter and the instrument integrated into a robotic operation. The robotic operation will optimise our programme which requires our target stars to be measured on a nightly basis. We present an overview of the entire project, including a description of our anticipated robotic operation.
The Magdalena Ridge Observatory Interferometer (MROI) was the most ambitious infrared interferometric facility conceived of in 2003 when funding began. Today, despite having suffered some financial short-falls, it is still one of the most ambitious interferometric imaging facilities ever designed. With an innovative approach to attaining the original goal of fringe tracking to H = 14th magnitude via completely redesigned mobile telescopes, and a unique approach to the beam train and delay lines, the MROI will be able to image faint and complex objects with milliarcsecond resolutions for a fraction of the cost of giant telescopes or space-based facilities. The design goals of MROI have been optimized for studying stellar astrophysical processes such as mass loss and mass transfer, the formation and evolution of YSOs and their disks, and the environs of nearby AGN.
The global needs for Space Situational Awareness (SSA) have moved to the forefront in many communities as Space becomes a more integral part of a national security portfolio. These needs drive imaging capabilities ultimately to a few tens of centimeter resolution at geosynchronous orbits. Any array capable of producing images on faint and complex geosynchronous objects in just a few hours will be outstanding not only as an astrophysical tool, but also for these types of SSA missions. With the recent infusion of new funding from the Air Force Research Lab (AFRL) in Albuquerque, NM, MROI will be able to attain first light, first fringes, and demonstrate bootstrapping with three telescopes by 2020.
MROI’s current status along with a sketch of our activities over the coming 5 years will be presented, as well as clear opportunities to collaborate on various aspects of the facility as it comes online. Further funding is actively being sought to accelerate the capability of the array for interferometric imaging on a short time-scale so as to achieve the original goals of this ambitious facility
This paper presents the latest optical design for the MOONS triple-arm spectrographs. MOONS will be a Multi-Object
Optical and Near-infrared Spectrograph and will be installed on one of the European Southern Observatory (ESO) Very
Large Telescopes (VLT). Included in this paper is a trade-off analysis of different types of collimators, cameras,
dichroics and filters.
The fast tip-tilt (FTT) correction system for the Magdalena Ridge Observatory Interferometer (MROI) is being developed by the University of Cambridge. The design incorporates an EMCCD camera protected by a thermal enclosure, optical mounts with passive thermal compensation, and control software running under Xenomai real-time Linux. The complete FTT system is now undergoing laboratory testing prior to being installed on the first MROI unit telescope in the fall of 2014. We are following a twin-track approach to testing the closed-loop performance: tracking tip-tilt perturbations introduced by an actuated flat mirror in the laboratory, and undertaking end-to-end simulations that incorporate realistic higher-order atmospheric perturbations. We report test results that demonstrate (a) the high stability of the entire opto-mechanical system, realized with a completely passive design; and (b) the fast tip-tilt correction performance and limiting sensitivity. Our preliminary results in both areas are close to those needed to realise the ambitious stability and sensitivity goals of the MROI which aims to match the performance of current natural guide star adaptive optics systems.
The Magdalena Ridge Observatory Interferometer has been designed to be a 10 × 1.4 m aperture long-baseline optical/near-infrared interferometer in an equilateral "Y" configuration, and is being deployed west of Socorro, NM on the Magdalena Ridge. Unfortunately, first light for the facility has been delayed due to the current difficult funding regime, but during the past two years we have made substantial progress on many of the key subsystems for the array. The design of all these subsystems is largely complete, and laboratory assembly and testing, and the installation and site acceptance testing of key components on the Ridge are now underway. This paper serves as an overview and update on the facility's present status and changes since 2012, and the plans for future activities and eventual operations of the facilities.
MOONS is a new Multi-Object Optical and Near-infrared Spectrograph selected by ESO as a third generation
instrument for the Very Large Telescope (VLT). The grasp of the large collecting area offered by the VLT (8.2m
diameter), combined with the large multiplex and wavelength coverage (optical to near-IR: 0.8μm - 1.8μm) of MOONS
will provide the European astronomical community with a powerful, unique instrument able to pioneer a wide range of
Galactic, Extragalactic and Cosmological studies and provide crucial follow-up for major facilities such as Gaia,
VISTA, Euclid and LSST. MOONS has the observational power needed to unveil galaxy formation and evolution over
the entire history of the Universe, from stars in our Milky Way, through the redshift desert, and up to the epoch of very
first galaxies and re-ionization of the Universe at redshift z>8-9, just few million years after the Big Bang. On a
timescale of 5 years of observations, MOONS will provide high quality spectra for >3M stars in our Galaxy and the
local group, and for 1-2M galaxies at z>1 (SDSS-like survey), promising to revolutionise our understanding of the
The baseline design consists of ~1000 fibers deployable over a field of view of ~500 square arcmin, the largest patrol
field offered by the Nasmyth focus at the VLT. The total wavelength coverage is 0.8μm-1.8μm and two resolution
modes: medium resolution and high resolution. In the medium resolution mode (R~4,000-6,000) the entire wavelength
range 0.8μm-1.8μm is observed simultaneously, while the high resolution mode covers simultaneously three selected
spectral regions: one around the CaII triplet (at R~8,000) to measure radial velocities, and two regions at R~20,000 one
in the J-band and one in the H-band, for detailed measurements of chemical abundances.
The Magdalena Ridge Observatory Interferometer has been designed to be a 10 x 1.4 m aperture long-baseline
optical/near-infrared interferometer in an equilateral "Y" configuration, and is being deployed west of Socorro, NM on
the Magdalena Ridge. Unfortunately, first light for the facility has been delayed due to the current difficult funding
regime, but during the past two years we have made substantial progress on many of the key subsystems for the array.
The design of all these subsystems is largely complete, and laboratory assembly and testing, and the installation of many of its components on the Ridge are now underway. This paper serves as an overview and update on the facility's present status, and the plans for future funding and eventual operations of the facilities.
Most subsystems of the Magdalena Ridge Observatory Interferometer (MROI) have progressed towards
final mechanical design, construction and testing since the last SPIE meeting in San Diego - CA. The first
1.4-meter telescope has successfully passed factory acceptance test, and construction of telescopes #2 and
#3 has started. The beam relay system has been prototyped on site, and full construction is awaiting
funding. A complete 100-meter length delay line system, which includes its laser metrology unit, has been
installed and tested on site, and the first delay line trolley has successfully passed factory acceptance
testing. A fully operational fringe tracker is integrated with a prototyped version of the automated
alignment system for a closed looping fringe tracking experiment. In this paper, we present details of the
final mechanical and opto-mechanical design for these MROI subsystems and report their status on
fabrication, assembly, integration and testing.
The fast tip-tilt correction system for the Magdalena Ridge Observatory Interferometer (MROI) is being designed and fabricated by the University of Cambridge. The design of the system is currently at an advanced stage and the performance of its critical subsystems has been verified in the laboratory. The system has been designed to meet a demanding set of specifications including satisfying all performance requirements in ambient temperatures down to -5 °C, maintaining the stability of the tip-tilt fiducial over a 5 °C temperature change without recourse to an optical reference, and a target acquisition mode with a 60” field-of-view. We describe the important technical features of the system, which uses an Andor electron-multiplying CCD camera protected by a thermal enclosure, a transmissive optical system with mounts incorporating passive thermal compensation, and custom control software running under Xenomai real-time Linux. We also report results from laboratory tests that demonstrate (a) the high stability of the custom optic mounts and (b) the low readout and compute latencies that will allow us to achieve a 40 Hz closed-loop bandwidth on bright targets.
The delay lines for the Magdalena Ridge Observatory Interferometer in New Mexico are required to provide up to 380m
optical path delay with an OPD jitter of better than 15nm, in vacuum, using a single adjustable stroke. In order to meet
these demanding requirements in a cost-effective manner a unique combination of techniques has been used in the design
and construction of the delay line trolley which operates continuously within 190m of evacuated pipe. These features
include contactless delivery of power and control signals, active control of the cat's eye optics and the use of composite
materials to achieve good thermal stability. A full-size prototype trolley has been built and fully tested and the first
production trolley is under construction. We describe the system's key design features and review the construction and
alignment of the delay line trolley. Results obtained with the trolley operating in an evacuated 20m-long test rig under
the full range of conditions required for successful astronomical observations are presented. An OPD jitter of typically
10nm is achieved over the total tracking velocity range from 0 to 15mm/s.
The Magdalena Ridge Observatory Interferometer is a 10 x 1.4 meter aperture long baseline optical and near-infrared
interferometer being built at 3,200 meters altitude on Magdalena Ridge, west of Socorro, NM. The interferometer layout
is an equilateral "Y" configuration to complement our key science mission, which is centered on imaging faint and
complex astrophysical targets. This paper serves as an overview and update on the status of the observatory and our
progress towards first light and first fringes in 2012.
We report on the mechanical design currently performed at the Magdalena Ridge Observatory
Interferometer (MROI) and how the construction, assembly, integration and verification are planned
towards commissioning. Novel features were added to the mechanical design, and high level of automation
and reliability are being devised, which allows the number of reflections to be kept down to a minimum
possible. This includes unit telescope and associated enclosure and transporter, fast tip-tilt system, beam
relay system, delay line system, beam compressor, automated alignment system, beam turning mirror,
switchyard, fringe tracker and vacuum system.
We report on test results on the delay line system for the MRO Interferometer, currently under construction
in Cambridge, UK. The delay lines are designed to provide 380 metres of vacuum path delay in a single stage,
offering rapid star-to-star slews, high throughput and high transmitted wavefront quality. Details of the final
design adopted for these delay lines are presented, together with lessons learnt from successful performance tests
of the full-scale prototype trolley in a 20-metre long vacuum test rig. Delivery of the first production trolley is
expected in New Mexico in early 2009.
The delay lines for the Magdalena Ridge Observatory Interferometer (MROI) will provide remote control of
optical delays of up to 380m with sub-wavelength precision in vacuum. The delay-line prototype is now fully
functional, all features having been demonstrated in a 20m long evacuated test rig. We describe the architecture,
design and performance of the delay line software: this features distributed real-time control and flexible remote
logging of diagnostic data from the delay line hardware components at up to 5 kHz.
The Magdalena Ridge Observatory Interferometer is a 10-element 1.4 meter aperture optical and near-infrared
interferometer being built at 3,200 meters altitude on Magdalena Ridge, west of Socorro, NM. The
interferometer layout is an equilateral "Y" configuration to complement our key science mission, which is
centered around imaging faint and complex astrophysical targets. This paper serves as an overview and
update on the status of the observatory and our progress towards first light and first fringes in the next few
The delay lines currently under development for the MRO Interferometer will provide up to 380m of optical delay
with only 3 reflections. We describe the novel aspects of the delay line design which include using the inside walls
of the vacuum pipes as "rails", active shear compensation, and replacing dragged cables with contactless power
transfer and communication. We describe the results of tests of various of these design concepts, and progress
on the design and construction of the prototype trolley.
We present a summary of activity at the Cambridge Optical Aperture Synthesis Telescope (COAST) group
during the period 2004-2006. Our main program has focused on technical design and prototyping for future
facility arrays such as the VLTI and Magdalena Ridge Observatory Interferometer, but with a small parallel
effort of focused astronomical observations with COAST, in particular multi-wavelength studies of supergiants.
We report on progress on these and other technical areas over the past 2 years.
The William Herschel Telescope (WHT) has an adaptive optics (AO) suite consisting of the AO system NAOMI, near IR imager INGRID, optical field spectrograph OASIS and coronagraph OSCA. GRACE (GRound based Adaptive optics Controlled Environment) is a dedicated structure at a Nasmyth focus designed to facilitate routine AO use by providing a controlled environment for the instrument system. However, GRACE is not just a building; it is all of the systems associated with providing the controlled environment, especially the control of air quality, temperature and flow. A key concern was that adding the GRACE building to the Nasmyth platform would not adversely change the telescope performance. This paper gives the background to GRACE, its specification and design, the building construction and installation, the environmental controls installed and their performance, the services provided, the effect of the new structure on telescope performance, the results of the project, including the effect having a controlled environment on AO performance and its planned use for a Rayleigh laser guide star system.
The Visual and Infra-red Survey Telescope for Astronomy, or VISTA, is a UK funded four meter class wide-field infra-red and optical survey telescope to be situated in Chile. The telescope, which is regarded as a two-channel camera, was funded on the basis of having a one-degree, infra-red field at the Cassegrain focus and a two degree, optical field at prime focus. The re-use, development or sharing of existing telescope system designs will play a major role in the project and thus pose particular design challenges and trades. This paper briefly outlines the science specification and the functional requirements of the telescope/camera together with the initial technical concepts and options. The unique or interesting features of this type of system are also discussed. The newly appointed project office, its project organization and plan are briefly described. An integrated systems engineering approach to the project, which is being developed, is also outlined.
This paper describes the selection process for the encoding system of the main (azimuth and elevation) axes of the Gemini 8-m telescopes. The main part of this is the description and results of lab tests carried out on competing systems. Two tape encoder solutions existed, one based on an inductive tape and one based on an optical tape, but neither met all the requirements. The optical system provided the better error performance, but its robustness was questionable and it was difficult to interface to the rest of the Gemini servo hardware. The inductive system was already proven to be robust and provided a standard quadrature encoder output. However, the system didn't meet some of the performance requirements and was not supplied as a complete system. The lab tests were carried out to try and resolve some of these problems and to help arrive at a decision between the two systems. The results showed that the error performance of both systems, in the presence of compensation, was good enough for the telescope application. The final decision was based upon a formal tender exercise that compared many properties of each system.
This paper describes the design and current status of the mount control system (MCS) for the Gemini telescopes. The MCS is responsible for the interface between the telescope computer system (TCS) and the hardware systems that are used to move the telescope's two main axes (azimuth and elevation). In order to do this, the MCS must process encoder signals and use these to close a position servo involving multiple motors. The MCS also provides several ancillary functions. These are: the servos for the main axis cable wraps, the servos for the telescopes counterbalance units, an interface to the safety interlock system and inputs for various sensors that will be placed around the telescope structure.
A number of improvements have been made to the servo control systems of the 4.2 m William Herschel Telescope (WHT) at the Isaac Newton Group of telescopes on La Palma in the Canary Islands. The successful upgrading of both the Cassegrain and prime focus rotators to meet more stringent science and engineering requirements is described. Simulation (using MatlabR and SimulinkR) of a model reference adaptive controller to improve azimuth tracking in the presence of torque disturbances is presented together with some preliminary results and a discussion of the way forward. Further enhancements to the WHT's subsystems are also discussed. The smaller 2.5 m Isaac Newton Telescope (INT) and the 1 m Jacobus Kapteyn Telescope (JKT) are also being considered for major improvements to their drives and encoders. Studies are being carried out to determine the requirements and appropriate goals of such improvements and whether modern control approaches can offer cost-effective solutions with minimal re-engineering work. The current performance, generally pointing and tracking, of these telescopes is presented and the subsystems which limit performance are examined; these may be drives, encoders, mirror supports, and structural components. A range of solutions is considered and the technical proposals developed so far are discussed.
The RGO is involved in a number of mirror support programs, ranging from new controllers for its existing Isaac Newton Group (ING) telescopes to new primary mirror supports for the UK Infra-red Telescope (UKIRT) and design proposals for the active support of the Gemini 8 m meniscus mirrors. This work has led to the identification or development of critical components such as load cells and control valves which have high precision and stability. Even so it is still necessary to develop servo controllers capable of minimizing the effects of non- linearity and maintaining stability, particularly in regard to the highly non-linear behavior of pneumatic supports. In order to predict the performance of mirror supports and compare differing control strategies, components and systems are modelled using MatlabR and SimulinkR. These models are presented, together with parameters derived experimentally, and results from recent laboratory tests are discussed. Specific applications are described and current status of the work at the time of submission is presented.
Large, modern optical telescopes demand high performance pointing and tracking of the mount unless alternative methods of correcting the telescope `beam' are to be completely relied upon. This is rarely the case and `open-loop' specifications are still very demanding. The move from precision-geared to friction driven axes has excluded the use of gear-driven encoders while friction-driven encoders have not proved successful. Fiber and laser gyros are not sufficiently developed for use as a primary encoding system although they have useful inertial properties for inclusion in some systems. Tape encoders, which have been around for a very long time, are the major contender for today's applications. A commercially available inductive tape encoder system has been fitted to the 4.2 m William Herschel Telescope in order to properly evaluate its performance and hence its suitability for use with the 8 m Gemini telescopes. The encoder system and the method adopted for fitting it to an operational telescope is briefly described and the results from performance tests are presented. Subsequent investigations into sources of error and the desirability and methods of correcting them are discussed and future work is considered.
The CCD autoguider detector system for the William Herschel Telescope (WHT) comprises a Peltier cooled, slow-scan CCD camera supported by an MC68020-based VME computer for image processing. The detector is a fluorescent dye coated EEV P8603 CCD chip operated in frame transfer mode. The CCD controller enables a full image to be read out during acquisition, but with windowed readout during guiding so as to permit an increased frame rate. The windowing is controlled by the VME computer, which is also used to calculate the centroid of the guide star and provides a local user interface, displaying images and guider status information. Special attention has been paid to the CCD drive clocks and bias voltages, enabling a very low dark current to be achieved (2 electrons per pixel per second at -35 C) without the need for extreme cooling. Guiding to magnitude 19 on the WHT has been demonstrated during dark time, with an integration time of one second.