Astronomical instrumentation

Abstract:

As part of the Phase A study for the EPICS instrument, we investigate if there are any contrast limitations imposed by the choice of the integral field spectrograph (IFS) technology, and if so, to determine the contrast limits applicable to each technology. In this document we investigate (through simulations) the contrast limitations inherent in a slicer based IFS. Current results show the achievable contrast with the slicer to be promising when taking into consideration the fact that the central region of the apodized PSF has not been masked. Limiting the maximum intensity by a factor of 100-1000 using an obscuring focal plane mask should also reduce the intensity of the secondary speckles by an equivalent factor. Furthermore, the secondary speckles created in the slicer spectrograph only influence the few slices where the bright central core is imaged. By orienting these slices to lie along the spider arms of the E-ELT secondary, the fraction of the field of view affected can be minimized. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

KMOS is a second generation instrument in construction for use at the European Southern Observatory (ESO) Very Large Telescope (VLT). It operates in the near-infrared (0.8 to 2.5 microns) and employs 24 deployable, image slicing integral field units (IFUs) feeding three spectrographs. The spectrographs are designed and built by a partnership of the University of Oxford and Rutherford Appleton Laboratories (RAL). We describe the assembly, integration and alignment procedures involved in the construction of these spectrographs in detail. We also present the results of the cryogenic optical tests, including the first data taken through the full spectrograph optical train and the details of the test facility and procedures involved. © 2010 Copyright SPIE - The International Society for Optical Engineering.

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.