The optical design of MOONS, the next generation thousand-fiber NIR spectrograph for the VLT, involves both on-axis reflective collimators and on-axis very fast reflective cameras, which yields both beam obstruction, due to fiber slit and detector support, and image spread, due to propagation within detector substrate. The need to model and control i) the effect of the diffraction spikes produced by these obstructions, ii) the detector-induced shape variation of the Point Spread Function (PSF), and iii) the intensity profile of the PSF wings, leads us to perform both simulations and lab measurements, in order to optimize the spider design and built a reliable PSF model, useful for simulate realistic raw images for testing the data reduction. Starting from the unobstructed PSF variation, as computed with the ZEMAX software, we numerically computed the diffraction spikes for different spider shapes, to which we added the PSF wing profile, as measured on a sample of the MOONS VPH diffraction grating. Finally, we implemented the PSF defocusing due to the thick detector (for the visible channel), we convolved the PSF with the fiber core image, and we added the optical ghosts, so finally obtaining a detailed and realistic PSF model, that we use for spectral extraction testing, cross talk estimation, and sensitivity predictions.

The EAGLE and EVE Phase A studies for instruments for the European Extremely Large Telescope (E-ELT) originated from related top-level scientific questions, but employed different (yet complementary) methods to deliver the required observations. We re-examine the motivations for a multi-object spectrograph (MOS) on the E-ELT and present a unified set of requirements for a versatile instrument. Such a MOS would exploit the excellent spatial resolution in the near-infrared envisaged for EAGLE, combined with aspects of the spectral coverage and large multiplex of EVE. We briefly discuss the top-level systems which could satisfy these requirements in a single instrument at one of the Nasmyth foci of the E-ELT.

MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A study. 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 0.8um-1.8um and two resolution modes: medium resolution and high resolution. In the medium resolution mode (R=4,000-6,000) the entire wavelength range 0.8um-1.8um 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 grasp of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and wavelength coverage of MOONS - extending into the near-IR - will provide the observational power necessary to study galaxy formation and evolution over the entire history of the Universe, from our Milky Way, through the redshift desert and up to the epoch of re-ionization at z>8-9. At the same time, the high spectral resolution mode will allow astronomers to study chemical abundances of stars in our Galaxy, in particular in the highly obscured regions of the Bulge, and provide the necessary follow-up of the Gaia mission. Such characteristics and versatility make MOONS the long-awaited workhorse near-IR MOS for the VLT, which will perfectly complement optical spectroscopy performed by FLAMES and VIMOS.

We present the design of an instrument which is capable of providing a legacy survey of the dust mineralogy of the galactic interstellar medium. It will measure the N-band spectra and images of a wide range of galactic targets, selected from the MSX and Akari missions, with an instantaneous field of view of 5 x 10 arcseconds(2). An integral field unit will sample this field at a spatial resolution of 0.2 arcseconds, with a grating spectrometer then dispersing the full 7 to 13 mu m waveband onto a 1024 x 1024 pixel(2) detector at a spectral resolving power of around 700. The absence of cryo-mechanisms and the utilisation of an existing design of integral field unit all contribute to the instrument having low development, build and operational costs.

The MIRI Medium Resolution Spectrometer (MIRI-MRS) will increase the sensitivity of astronomical spectroscopy at thermal infrared wavelengths (from 5 to 28 microns), by a factor of 1000 over the best that can be achieved by existing ground-based instruments. This leap in performance is further enhanced by the first use at these wavelengths of all reflective Integral Field Units (image slicers) to provide the spectrometer with a rectangular field of view with a shortest dimension of 3.5 arcseconds. We describe the optical design of the MRS and present predictions for its delivered image quality.

We have developed a novel light source for flat fielding and transmission monitoring of the Mid-Infrared Instrument on the JWST. The source uses a hot tungsten filament, mounted in a hemispherical, non-imaging flux concentrator. The design is compact, with the hemisphere having a diameter of 20 mm, and dissipates only 10 milliWatts of electrical power when operating.We describe the most important features of the design, and present the first measurements of its photometric performance.

A prototype cryogenic 'pick-off' arm for selecting a small field from the focal plane of a large telescope has been built and tested against a set of scientific requirements representative of those for proposed multi-integral-field spectrographs. In this paper, we present the design of the arm and the results of the cryogenic testing. Since the proposed instruments will require tens of arms, perhaps hundreds, we have also considered the industrialisation of the manufacture and assembly of the arms. We briefly discuss this aspect of the design and the possibilities for future instrumentation on Extremely Large Telescopes.

We present the design of an instrument which is capable of providing a legacy survey of the dust mineralogy of the galactic interstellar medium. It will measure the N-band spectra and images of a wide range of galactic targets, selected from the MSX and Akari missions, with an instantaneous field of view of 5×10 arcseconds2. An integral field unit will sample this field at a spatial resolution of 0.2 arcseconds, with a grating spectrometer then dispersing the full 7 to 13 μm waveband onto a 1024×1024 pixel2 detector at a spectral resolving power of around 700. The absence of cryo-mechanisms and the utilisation of an existing design of integral field unit all contribute to the instrument having low development, build and operational costs.