This conference presentation was prepared for the Quantum Technology: Driving Commercialisation of an Enabling Science III conference at SPIE Photonex, 2022.
This paper investigates the potential role of small satellites, specifically those often referred to as CubeSats, in the future of infrared astronomy. Whilst CubeSats are seen as excellent (and inexpensive) ways to demonstrate and improve the readiness of critical (space) technologies of the future they also potentially have a role in solving key astrophysical problems. The pros and cons of such small platforms are considered and evaluated with emphasis on the technological limitations and how these might be improved. Three case studies are presented for applications in the IR region. One of the main challenges of operating in the IR is that the detector invariably needs to be cooled. This is a significant undertaking requiring additional platform volume and power and is one of the major areas of discussion in this paper. Whilst the small aperture on a CubeSat inevitably has limitations both in terms of sensitivity and angular resolution when compared to large ground-based and space-borne telescopes, the prospect of having distributed arrays of tens (perhaps hundreds) of IR-optimised CubeSats in the future offers enormous potential. Finally, we summarise the key technology developments needed to realise the case study missions in the form of a roadmap.
Adaptive optics is essential for the successful operation of the future Extremely Large Telescopes (ELTs). At the heart of these AO system lies the real-time control which has become computationally challenging. A majority of the previous efforts has been aimed at reducing the wavefront reconstruction latency by using many-core hardware accelerators such as Xeon Phis and GPUs. These modern hardware solutions offer a large numbers of cores combined with high memory bandwidths but have restrictive input/output (I/O). The lack of efficient I/O capability makes the data handling very inefficient and adds both to the overall latency and jitter. For example a single wavefront sensor for an ELT scale adaptive optics system can produce hundreds of millions of pixels per second that need to be processed. Passing all this data through a CPU and into GPUs or Xeon Phis, even by reducing memory copies by using systems such as GPUDirect, is highly inefficient.
The Mellanox TILE series is a novel technology offering a high number of cores and multiple 10 Gbps Ethernet ports. We present results of the TILE-Gx36 as a front-end wavefront sensor processing unit. In doing so we are able to greatly reduce the amount of data needed to be transferred to the wavefront reconstruction hardware. We show that the performance of the Mellanox TILE-GX36 is in-line with typical requirements, in terms of mean calculation time and acceptable jitter, for E-ELT first-light instruments and that the Mellanox TILE series is a serious contender for all E-ELT instruments.
The tropospheric distribution of greenhouse gases (GHGs) depends on surface flux variations, atmospheric chemistry and transport processes over a range of spatial and temporal scales. Accurate and precise atmospheric concentration observations of GHGs can be used to infer surface flux estimates, though their interpretation relies on unbiased atmospheric transport models. GHOST is a novel, compact shortwave infrared spectrometer which will observe tropospheric columns of CO2, CO, CH4 and H2O (along with the HDO/H2O ratio) during deployment on board the NASA Global Hawk unmanned aerial vehicle. The primary science objectives of GHOST are to: 1) test atmospheric transport models; 2) evaluate satellite observations of GHG column observations over oceans; and 3) complement in-situ tropopause transition layer observations from other Global Hawk instruments. GHOST comprises a target acquisition module (TAM), a fibre slicer and feed system, and a multiple order spectrograph. The TAM is programmed to direct solar radiation reflected by the ocean surface into a fibre optic bundle. Incoming light is then split into four spectral bands, selected to optimise remote observations of GHGs. The design uses a single grating and detector for all four spectral bands. We summarise the GHOST concept and its objectives, and describe the instrument design and proposed deployment aboard the Global Hawk platform.
We present wavefront reconstruction acceleration of high-order AO systems using an Intel Xeon Phi processor. The Xeon Phi is a coprocessor providing many integrated cores and designed for accelerating compute intensive, numerical codes. Unlike other accelerator technologies, it allows virtually unchanged C/C++ to be recompiled to run on the Xeon Phi, giving the potential of making development, upgrade and maintenance faster and less complex. We benchmark the Xeon Phi in the context of AO real-time control by running a matrix vector multiply (MVM) algorithm. We investigate variability in execution time and demonstrate a substantial speed-up in loop frequency. We examine the integration of a Xeon Phi into an existing RTC system and show that performance improvements can be achieved with limited development effort.
HARPS-N (High-Accuracy Radial-Velocity planetary Search) is an instrument designed for the measurement of Radial
Velocities (RV) at highest accuracy. It is located in the Northern hemisphere and installed at the TNG on La Palma
Island. It has allowed scientists to confirm and characterize Earth-like mass planets: Kepler-78b. In this paper, we
present the design of Instrument Control Software (ICS) based on LabVIEW, the key features of implementation such as
the XML-RPC, labVIEW Classes and Shared Variables. We also present here the auto-guiding and fibre hole finding
algorithm. Use of XML-RPC in Labview for ICS with COTS hardware has made the development of HARAPS-N ICS
easily in implementing and integrating with other software in a limited construction time scale.
The measurement of the atmospheric concentration of greenhouse gases such as carbon dioxide (CO2) requires the simultaneous observation of a number of wavelength channels. Current and planned CO2 missions typically measure three wavebands using a hyperspectral sensor containing three spectrometers fed by an optical relay system to separate the wavelength channels. The use of one spectrometer per wavelength channel is inefficient in terms of number of detectors required and the mass and volume. This paper describes the development of an alternative solution which uses two key technologies to enable a more compact design; an image slicer mirror placed at the focal plane, and a multiple slit spectrometer operating in multiple diffraction orders. Both of these technologies are in common use in advanced astronomical spectrometers on large telescopes. The imager slicer mirror technology, as used on the James Webb Space Telescope instrument MIRI, enables the spectrometer to be illuminated with three input slits, each at a different wavelength. The spectrometer then disperses the light into multiple diffraction orders, via an echelle grating, to simultaneously capture spectra for three wavelength channels.
The Telescopio Nazionale Galileo (TNG)[9] hosts, starting in April 2012, the visible spectrograph HARPS-N. It is based
on the design of its predecessor working at ESO's 3.6m telescope, achieving unprecedented results on radial velocity
measurements of extrasolar planetary systems. The spectrograph's ultra-stable environment, in a temperature-controlled
vacuum chamber, will allow measurements under 1 m/s which will enable the characterization of rocky, Earth-like
planets. Enhancements from the original HARPS include better scrambling using octagonal section fibers with a shorter
length, as well as a native tip-tilt system to increase image sharpness, and an integrated pipeline providing a complete set
of parameters.
Observations in the Kepler field will be the main goal of HARPS-N, and a substantial fraction of TNG observing time
will be devoted to this follow-up. The operation process of the observatory has been updated, from scheduling
constraints to telescope control system. Here we describe the entire instrument, along with the results from the first
technical commissioning.
HARPS North is the twin of the HARPS (High Accuracy Radial velocity for Planetary Search) spectrograph operating in
La Silla (Chile) recently installed on the TNG in La Palma observatory and used to follow-up, the "hot" candidates
delivered by the Kepler satellite. HARPS-N is delivered with its own software that completely integrates with the TNG
control system. A special care has been dedicated to develop tools that will assist the astronomers during the whole
process of taking images: from the observation schedule to the raw image acquisition. All these tools are presented in the
paper. In order to provide a stable and reliable system, the software has been developed keeping in mind concepts like
failover and high-availability. HARPS-N is made of heterogeneous systems, from normal computer to real-time systems,
that's why the standard message queue middleware (ActiveMQ) was chosen to provide the communications between
different processes. The path of operations starting with the Observation Blocks and ending with the FITS frames is fully
automated and could allow, in the future, the completely remote observing runs optimized for the time and quality
constraints.
We present a conceptual design for a Precision Radial Velocity Spectrograph (PRVS) for the Gemini telescope. PRVS is
a fibre fed high resolving power (R~70,000 at 2.5 pixel sampling) cryogenic echelle spectrograph operating in the near
infrared (0.95 - 1.8 microns) and is designed to provide 1 m/s radial velocity measurements. We identify the various
error sources to overcome in order to the required stability. We have constructed models simulating likely candidates
and demonstrated the ability to recover exoplanetary RV signals in the infrared. PRVS should achieve a total RV error of
around 1 m/s on a typical M6V star. We use these results as an input to a simulated 5-year survey of nearby M stars.
Based on a scaling of optical results, such a survey has the sensitivity to detect several terrestrial mass planets in the
habitable zone around nearby stars. PRVS will thus test theoretical planet formation models, which predict an abundance
of terrestrial-mass planets around low-mass stars.We have conducted limited experiments with a brass-board instrument
on the Sun in the infrared to explore real-world issues achieving better than 10 m/s precision in single 10 s exposures and
better than 5 m/s when integrated across a minute of observing.
An update on the design status of the UKIRT Wide Field Camera (WFCAM) is presented. WFCAM is a wide field infrared camera for the UK Infrared Telescope, designed to produce large scale infrared surveys. The complete system consists of a new IR camera with integral autoguider and a new tip/tilt secondary mirror unit. WFCAM is being designed and built by a team at the UK Astronomy Technology Centre in Edinburgh, supported by the Joint Astronomy Centre in Hawaii. The camera uses a novel quasi-Schmidt camera type design, with the camera mounted above the UKIRT primary mirror. The optical system operates over 0.7 - 2.4 μm and has a large corrected field of view of 0.9° diameter. The focal plane is sparsely populated with 4 2K x 2K Rockwell HAWAII-2 MCT array detectors, giving a pixel scale of 0.4 arcsec/pixel. A separate autoguider CCD is integrated into the focal plane unit. Parallel detector controllers are used, one for each of the four IR arrays and a fifth for the autoguider CCD.
NAOMI (Nasmyth Adaptive Optics for Multi-purpose Instrumentation) is a recently completed and commissioned astronomical facility on the 4.2m William Herschel Telescope. The system is designed to work initially with Natural Guide Stars and also to be upgradeable for use with a single laser guide star. It has been designed to work with both near infrared and optical instrumentation (both imagers and spectrographs). The system uses a linearised segmented adaptive mirror and dual-CCD Shack-Hartmann wavefront sensor together with a multiple-DSP real-time processing system. Control system parameters can be updated on-the-fly by monitoring processes and the system can self-optimize its base optical figure to compensate for the optical characteristics of attached scientific instrumentation. The scientific motivation, consequent specification and implementation of NAOMI are described, together with example performance data and information on future upgrades and instrumentation.
KEYWORDS: Cameras, Digital signal processing, Control systems, Global Positioning System, Stars, Telescopes, Astronomy, Clocks, Imaging systems, Charge-coupled devices
Ultracam is a high speed, three channel CCD camera designed to provide imaging photometry at high temporal resolution, allowing the study of rapidly changing astronomical phenomena such as eclipses, rapidly flickering light curves and occultation events. It is designed to provide frame rates up to 500 Hz with minimum inter-frame dead time and to time-tag each frame to within 1 millisecond of UT. The high data rates that this instrument produces, together with its use as a visitor instrument at a number of observatories, have lead to a highly modular design. Each major service (camera, control, sequencing, data handlers, etc.) is a separate process that communicates using XML documents via HTTP transport, allowing the services to be redeployed or reconfigured with minimal effort. The use of XML and HTTP also allows a web browser to act as a front end for any of the services, as well as providing easy access to services from other control systems. The overall design allows for simple re-engineering for a variety of imaging systems, and is already expected to provide control of IR arrays for the UKIRT Wide-Field Camera project. The instrument has been successfully commissioned on the William Herschel Telescope.
An astronomical AO system for use on a 4 m class telescope at visible wavelengths is described. The design of this instrument is based on the University of Durham semi common-user partial-AO system MARTINI. A brief technical resume and recent astronomical results are provided. The MARTINI system was designed on a partial, but non-modal, philosophy which is able to deliver modest image improvements normally associated with low order corrections at small D/ro. The new system will remove the limited aperture coverage of the MARTINI system and extend its operating philosophy to produce a corrected optical transfer function optimized to scientific goals. The requirements and resulting system design are described. The system is also designed to be accommodated within the general scheme of the UK national AO program which was initiated in 1993. A brief discussion of the design issues involved is provided.
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.