One of the key science goals for a diffraction limited imager on an Extremely Large Telescope (ELT) is the resolution of individual stars down to faint limits in distant galaxies. The aim of this study is to test the proposed capabilities of a multi-conjugate adaptive optics (MCAO) assisted imager working at the diffraction limit, in IJHK s filters, on a 42m diameter ELT to carry out accurate stellar photometry in crowded images in an Elliptical-like galaxy at the distance of the Virgo cluster. As the basis for realistic simulations we have used the phase A studies of the European-ELT project, including the MICADO imager (Davies & Genzel 2010) and the MAORY MCAO module (Diolaiti 2010). We convolved a complex resolved stellar population with the telescope and instrument performance expectations to create realistic images. We then tested the ability of the currently available photometric packages STARFINDER and DAOPHOT to handle the simulated images. Our results show that deep Colour-Magnitude Diagrams (photometric error, ±0.25 at I≥27.2; H≥25. and K s ≥24.6) of old stellar populations in galaxies, at the distance of Virgo, are feasible at a maximum surface brightness, µ V ∼ 17 mag/arcsec 2 (down to M I > −4 and M H ∼ M K > −6), and significantly deeper (photometric error, ±0.25 at I≥29.3; H≥26.6 and K s ≥26.2) for µ V ∼ 21 mag/arcsec 2 (down to M I ≥ −2 and M H ∼ M K ≥ −4.5). The photometric errors, and thus also the depth of the photometry should be improved with photometry packages specifically designed to adapt to an ELT MCAO Point Spread Function. We also make a simple comparison between these simulations and what can be expected from a Single Conjugate Adaptive Optics feed to MICADO and also the James Webb Space Telescope.
MICADO is the adaptive optics imaging camera for the E-ELT. It has been designed and optimised to be mounted to the LGS-MCAO system MAORY, and will provide diffraction limited imaging over a wide (∼1 arcmin) field of view. For initial operations, it can also be used with its own simpler AO module that provides on-axis diffraction limited performance using natural guide stars. We discuss the instrument's key capabilities and expected performance, and show how the science drivers have shaped its design. We outline the technical concept, from the opto-mechanical design to operations and data processing. We describe the AO module, summarise the instrument performance, and indicate some possible future developments. MICADO OVERVIEWMICADO is the Multi-AO Imaging Camera for Deep Observations, designed to work with adaptive optics (AO) on the E-ELT. It has been optimised for the multi-conjugate adaptive optics (MCAO) module MAORY; 1, 2 but it is also able to work with other adaptive optics systems, and includes a separate module to provide a single conjugate adaptive optics (SCAO) capability 3 using natural guide stars during early operations (see Section 4). As this simple AO mode sets low requirements on the telescope and facilities (e.g. no lasers are required), it is an optimum choice for demonstrating the scientific capabilities of the E-ELT at the earliest opportunity. The optical relay and support structure for SCAO provide the same opto-mechanical interface as MAORY, and in principle enable MICADO to be used with other AO systems such as ATLAS. 4 This phased approach means that MICADO will be able to make use of increasingly sophisticated AO systems as they become available.MICADO is compact and is supported underneath the AO systems so that it rotates in a gravity invariant orientation. It is able to image, through a large number of selected wide and narrow-band near infrared filters, a large 53 field of view at the diffraction limit of the E-ELT. MICADO has two arms. The primary arm is a high
An international round-robin experiment has been conducted to test procedures and methods for the measurement of angle resolved light scattering. ASTM E2387-05 has been used as the main guide, while the experience gained should also contribute to the new ISO standard of angle resolved scattering currently under development (ISO/WD 19986:2016). Seven laboratories from Europe and the USA measured the angle resolved scattering from Al/SiO 2 coated substrates, transparent substrates, volume diffusors, quasi volume diffusors, white calibration standards, and grating samples at laser wavelengths in the UV, VIS and NIR spectrum. Results were sent to Fraunhofer IOF that coordinated the experiments and analyzed the data, while ESA-ESTEC, as the project donor, defined conditions and parameters. Depending mainly on the sample type, overall good to reasonable agreements were observed, with largest deviations at scattering angles very close to the specular beam. Volume diffusor characterization unexpectedly turned out to be challenging. Not all participants provided measurement uncertainty ranges according to GUM, often, a single general scatterometer-related measurement uncertainty value was stated. Although relative instrument measurement uncertainties close to 1% are sometimes claimed, the comparison results did not support these claims for specular scattering samples as mirrors, substrates, or gratings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.