Publisher's Note: This paper, originally published on 18 July 2024, was replaced with a corrected/revised version on 30 August 2024. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.
MOSAIC is a wide-field spectrograph, combining multiple-object spectroscopy and integral field units, to cover the ELT focal plane with a field-of-view of 7.8 arcmin from the blue to the near-infrared, 390 to 1800nm. In the current Phase B design, AO is GLAO supported by four LGS in a fixed asterism and with multiple NGS. Although the GLAO correction is modest compared to other ELT instrumentation, the use of the integrated M4/M5 correction elements and the existing LGS allows for an efficient design which is outlined. MOSAIC GLAO will use the ELT PFS guide-probes to compensate for high- frequency tip/tilt errors, greatly relaxing the requirements on the instrumental NGS sensors. The Phase A architecture used the same pick-off mirrors as the IFU instruments to feed the NGS-WFS from anywhere in the focal plane, which was mandatory for the proposed MOAO design. The reduced performance requirements at Phase B allows us to take advantage, instead, of the four 2 arcmin diameter field-of-view through the LGS cutouts, arranged in a square pattern at an off-axis distance of 3.75 arcmin. In each LGS cutout, a wide-field-imager is implemented–alongside one LGS WFS–to acquire multiple NGS that supports both slow tip/tilt measurements, isolating instrument-Nasmyth flexure, solving for the astrometric distortion expected from errors in the ELT optical path, and supporting the alignment of MOS apertures with the field. The latter is a key requirement for MOSAIC, leading to 40mas accuracy in MOS aperture positioning and 40mas rotation displacement at the edge of the scientific field.
In this proceeding, we present the development of the Optical Ground Support Equipment (OGSE) used for payload-level testing of the Ariel space mission. Ariel is an ESA mission that will use the transit spectroscopy method to observe the atmospheres of nominally ~1000 exoplanets. Ariel is a 1 m class cryogenic (∼ 40 K) space telescope that will be placed in a halo orbit around the Earth-Sun L2 point. To detect atmospheric molecular absorption features, Ariel will produce medium-resolution spectra (R ≥ 15) using three spectroscopic channels covering 1.1 – 7.9 μm as well as having photometric channels covering 0.5 – 1.1 μm. To achieve Ariel’s science goals, the payload requires detailed calibration and performance verification. The payload-level performance verification of the Ariel payload will take place in 2026 in a 5-meter vacuum chamber at the Rutherford Appleton Laboratory’s Space Instruments Test Facility. The payload will be enclosed in a Cryogenic Test Rig (CTR) to provide a space-like (~35 K) thermal environment and is illuminated by the OGSE. The OGSE provides point as well as extended source illumination across Ariel’s full wavelength range. The OGSE design also includes a series of mechanisms and features to enable the various illumination conditions required to test Ariel. Here we report design updates to the OGSE after a preliminary design review (PDR). Since PDR, there have been substantial revisions to the OGSE architecture. In this proceeding, we describe the evolution of the OGSE architecture. The updated OGSE design will then be presented.
BlueMUSE is a blue-optimised, medium spectral resolution, panoramic integral eld spectrograph under development for the Very Large Telescope (VLT). With an optimised transmission down to 350 nm, spectral resolution of R~3500 on average across the wavelength range, and a large FoV (1 arcmin2), BlueMUSE will open up a new range of galactic and extragalactic science cases facilitated by its specific capabilities. The BlueMUSE consortium includes 9 institutes located in 7 countries and is led by the Centre de Recherche Astrophysique de Lyon (CRAL). The BlueMUSE project development is currently in Phase A, with an expected rst light at the VLT in 2031. We introduce here the Top Level Requirements (TLRs) derived from the main science cases, and then present an overview of the BlueMUSE system and its subsystems ful lling these TLRs. We speci cally emphasize the tradeo s that are made and the key distinctions compared to the MUSE instrument, upon which the system architecture is built.
MOSAIC is the Multi-Object Spectrograph (MOS) for the 39m Extremely Large Telescope (ELT) of the European Southern Observatory (ESO), with unique capabilities in terms of multiplex, wavelength coverage and spectral resolution. It is a versatile multi-object spectrograph working in both the Visible and NIR domains, designed to cover the largest possible area (∼40 arcmin2) on the focal plane, and optimized to achieve the best possible signal-to-noise ratio on the faintest sources, from stars in our Galaxy to galaxies at the epoch of the reionization. In this paper we describe the main characteristics of the instrument, including its expected performance in the different observing modes. The status of the project will be briefly presented, together with the positioning of the instrument in the landscape of the ELT instrumentation. We also review the main expected scientific contributions of MOSAIC, focusing on the synergies between this instrument and other major ground-based and space facilities.
MOSAIC is the Multi-Object Spectrograph for the ESO Extremely Large Telescope, approved to enter Phase B beginning 2022. It is conceived as a multi- purpose instrument covering the Visible and Near Infrared bandwidth (0.45 –1.8 μm) with two observing modes: spatially resolved spectroscopy with 8 integral field units; and the simultaneous observation of 200 objects in the VIS and NIR in unresolved spectroscopy.
We present an overview of the main MOSAIC science drivers and the actual baseline design for the instrument. The prototyping and developments undertaken by the consortium to evaluate the feasibility of the project are also discussed.
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