Prof Gavin Dalton

Abstract:

OPTIMOS-EVE (OPTical Infrared Multi Object Spectrograph - Extreme Visual Explorer) is the fiber fed multi object spectrograph proposed for the E-ELT. It is designed to provide a spectral resolution ranging from 5000 to 30.000, at wavelengths from 0.37 μm to 1.70 μm, combined with a high multiplex (>200) and a large spectral coverage. The system consists of three main modules: a fiber positioning system, fibers and a spectrograph. The OPTIMOS-EVE Phase-A study, carried out within the framework of the ESO E-ELT instrumentation studies, has been performed by an international consortium consisting of institutes from France, Netherlands, United Kingdom, Italy and Denmark. This paper describes the design tradeoff study and the key issues determining the price and performance of the instrument. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

ESA's cornerstone mission Gaia will construct a billion-star catalogue down to magnitude 20 but will only provide detailed chemical information for the brighter stars and will be lacking radial velocity at the faint end due to insufficient Signal-to-Noise Ratios (SNR). This calls for the deployment of a ground spectrograph under time scales coherent with those of Gaia for a complementary survey. The GYES instrument is a high resolution (∼ 20,000) spectrometer proposed for installation on the Canada- France-Hawaii Telescope (CFHT) to perform this survey in the northern hemisphere. It exploits the large Field of View (FoV) available at the prime focus together with a high multiplex (∼ 500 fibres) to achieve a SNR of 30 in two hours at magnitude 16 and render the survey possible on the order of 300 nights. The on-going feasibility study aims at jointly optimising all components of the system: the field corrector, the positioner, the fibres and the spectrograph. The key challenges consist in accommodating the components in the highly constrained environment of the primary focus, as well as in achieving maximum efficiency thanks to high transmission and minimum reconfiguration delays. Meanwhile, for GYES to have its first light at the time of Gaia's initial data release (2014-2015), it is mandatory to keep its complexity down by designing a predominantly passive instrument. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

OPTIMOS-EVE (OPTical Infrared Multi Object Spectrograph - Extreme Visual Explorer) is the fibre fed multi object spectrograph proposed for the European Extremely Large Telescope (E-ELT), planned to be operational in 2018 at Cerro Armazones (Chile). It is designed to provide a spectral resolution of 6000, 18000 or 30000, at wavelengths from 370 nm to 1.7 μm, combined with a high multiplex (>200) and a large spectral coverage. Additionally medium and large IFUs are available. The system consists of three main modules: a fibre positioning system, fibres and a spectrograph. The recently finished OPTIMOS-EVE Phase-A study, carried out within the framework of the ESO E-ELT instrumentation studies, has been performed by an international consortium consisting of institutes from France, Netherlands, United Kingdom and Italy. All three main science themes of the E-ELT are covered by this instrument: Planets and Stars; Stars and Galaxies; Galaxies and Cosmology. This paper gives an overview of the OPTIMOS-EVE project, describing the science cases, top level requirements, the overall technical concept and the project management approach. It includes a description of the consortium, highlights of the science drivers and resulting science requirements, an overview of the instrument design and telescope interfaces, the operational concept, expected performance, work breakdown and management structure for the construction of the instrument, cost and schedule. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

Fibre Multi-Object Spectrograph (FMOS) is the first near-infrared instrument with a wide field of view capable of acquiring spectra simultaneously from up to 400 objects. It has been developed as a common-use instrument for the F=2 prime-focus of the Subaru Telescope. The field coverage of 300 diameter is achieved using a new 3-element corrector optimized in the near-infrared (0.9-1.8μm) wavelength range. Due to limited space at the prime-focus, we have had to develop a novel fibre positioner, called " Echidna" , together with two OH-airglow suppressed spectrographs. FMOS consists of three subsystems: the prime focus unit for IR, the fibre positioning system/connector units, and the two spectrographs. After full systems integration, FMOS was installed on the telescope in late 2007. Many aspects of the performance were checked through various test and engineering observations. In this paper, we present the optical and mechanical components of FMOS, and show the results of our on-sky engineering observations to date. © 2010. Astronomical Society of Japan.

Abstract:

The OPTIMOS-EVE instrument proposed for the E-ELT aims to use the maximum field of view available to the E-ELT in the limit of natural or ground-layer-corrected seeing for high multiplex fibre-fed multi-object spectroscopy in the visible and near-IR. At the bare nasmyth focus of the telescope, this field corresponds to a focal plane 2.3m in diameter, with a plate-scale of ∼3mm/arcsec. The required positioning accuracy that is implied by seeing limited performance at this plate-scale brings the system into the range of performances of commercial off-the-shelf robots that are commonly used in industrial manufacturing processes. The cost-benefits that may be realized through such an approach must be offset against the robot performance, and the ease with which a useful software system can be implemented. We therefore investigate whether the use of such a system is indeed feasible for OPTIMOS-EVE, and the possibilities of extending this approach to other instruments that are currently in the planning stage. © 2010 SPIE.