Extremely Large Telescope

Abstract:

The Fibre Multi-Object Spectrograph for Subaru Telescope (FMOS) is a near-infrared instrument with 400 fibres in a 30' filed of view at F/2 prime focus. To observe 400 objects simultaneously, we have developed a fibre positioner called "Echidna" using a tube piezo actuator. We have also developed two OH-airglow suppressed and refrigerated spectrographs. Each spectrograph has two spectral resolution modes: the low-resolution mode and the high-resolution mode. The low-resolution mode covers the complete wavelength range of 0.9 - 1.8 μm with one exposure, while the high-resolution mode requires four exposures at different camera positions to cover the full wavelength range. The first light was accomplished in May 2008. The science observations and the open-use observations begin in May 2010. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Abstract:

We describe the results of a Phase A study for a single field, wide band, near-infrared integral field spectrograph for the European Extremely Large Telescope (E-ELT). HARMONI, the High Angular Resolution Monolithic Optical & Nearinfrared Integral field spectrograph, provides the E-ELT's core spectroscopic requirement. It is a work-horse instrument, with four different spatial scales, ranging from seeing to diffraction-limited, and spectral resolving powers of 4000, 10000 & 20000 covering the 0.47 to 2.45 μm wavelength range. It is optimally suited to carry out a wide range of observing programs, focusing on detailed, spatially resolved studies of extended objects to unravel their morphology, kinematics and chemical composition, whilst also enabling ultra-sensitive observations of point sources. We present a synopsis of the key science cases motivating the instrument, the top level specifications, a description of the opto-mechanical concept, operation and calibration plan, and image quality and throughput budgets. Issues of expected performance, complementarity and synergies, as well as simulated observations are presented elsewhere in these proceedings[1]. © 2010 Copyright SPIE - The International Society for Optical Engineering.

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.