Alignment and preliminary outcomes of an ELT-size instrument to a very large telescope: LINC-NIRVANA at LBT

LINC-NIRVANA (LN) is a high resolution, near infrared imager that uses a multiple field-of-view, layer-oriented, multi-conjugate AO system, consisting of four multi-pyramid wavefront sensors (two for each arm of the Large Binocular Telescope, each conjugated to a different altitude). The system employs up to 40 star probes, looking at up to 20 natural guide stars simultaneously. Its final goal is to perform Fizeau interferometric imaging, thereby achieving ELT-like spatial resolution (22.8 m baseline resolution). For this reason, LN is also equipped with a fringe tracker, a beam combiner and a NIR science camera, for a total of more than 250 optical components and an overall size of approximately 6x4x4.5 meters. This paper describes the tradeoffs evaluated in order to achieve the alignment of the system to the telescope. We note that LN is comparable in size to planned ELT instrumentation. The impact of such alignment strategies will be compared and the selected procedure, where the LBT telescope is, in fact, aligned to the instrument, will be described. Furthermore, results coming from early night-time commissioning of the system will be presented.Comment: 8 pages, 6 pages, AO4ELT5 Proceedings, 201

LINC-NIRVANA at LBT: final preparations for first light

LINC-NIRVANA is an innovative, high-resolution near-infrared imager for the Large Binocular Telescope. Its Multi- Conjugate Adaptive Optics system uses natural guide-stars and provides high sky coverage for single-eye, binocular, and eventually, interferometric observations. We report on final lab integration and system level testing, as well as technical and logistical challenges of shipping and installing a large, delicate, complex instrument. LINC-NIRVANA is currently at LBT undergoing final alignment and tests before First Light late this fall. Managing the transition to operations involves the interactions between telescope alignment and calibration, commissioning of the instrument, and executing the Early Science plan

MCAO with LINC-NIRVANA at LBT: preparing for first light

LINC-NIRVANA is an innovative, high-resolution, near-infrared imager for the Large Binocular Telescope. Its Multi-Conjugate Adaptive Optics system uses natural guide-stars and the layer-oriented, multiple-field of view approach for high sky coverage and eventual interferometric beam combination. We describe LINC-NIRVANA's particular flavour of MCAO and its associated challenges, and report on final lab integration and system level testing. LINC-NIRVANA is currently at the telescope undergoing final alignment and tests before First Light late this fall

The ESPRI project: astrometric exoplanet search with PRIMA I. Instrument description and performance of first light observations

The ESPRI project relies on the astrometric capabilities offered by the PRIMA facility of the Very Large Telescope Interferometer for the discovery and study of planetary systems. Our survey consists of obtaining high-precision astrometry for a large sample of stars over several years and to detect their barycentric motions due to orbiting planets. We present the operation principle, the instrument's implementation, and the results of a first series of test observations. A comprehensive overview of the instrument infrastructure is given and the observation strategy for dual-field relative astrometry is presented. The differential delay lines, a key component of the PRIMA facility which was delivered by the ESPRI consortium, are described and their performance within the facility is discussed. Observations of bright visual binaries are used to test the observation procedures and to establish the instrument's astrometric precision and accuracy. The data reduction strategy for astrometry and the necessary corrections to the raw data are presented. Adaptive optics observations with NACO are used as an independent verification of PRIMA astrometric observations. The PRIMA facility was used to carry out tests of astrometric observations. The astrometric performance in terms of precision is limited by the atmospheric turbulence at a level close to the theoretical expectations and a precision of 30 micro-arcseconds was achieved. In contrast, the astrometric accuracy is insufficient for the goals of the ESPRI project and is currently limited by systematic errors that originate in the part of the interferometer beamtrain which is not monitored by the internal metrology system. Our observations led to the definition of corrective actions required to make the facility ready for carrying out the ESPRI search for extrasolar planets.Comment: 32 pages, 39 figures, Accepted for publication in Astronomy and Astrophysic

Single conjugate adaptive optics for METIS

METIS, the Mid-infrared Imager and Spectrograph for the Extremely Large Telescope (ELT), is currently under development and has conducted the Preliminary Design Review in spring of 2019. An integral part of METIS is its Single Conjugate Adaptive Optics (SCAO) system, which will provide the required wavefront correction in conjunction with the adaptive mirrors in the telescope domain. It is optimized for the unique observing capabilities of METIS - especially for high contrast imaging in the mid-infrared. The coronagraphic observing modes impose a number of challenging requirements for adaptive and active beam correction. METIS SCAO is tasked to support all observing modes with AO wavefront correction, but also with differential tip/tilt-, NCPA-, and pupil position control. The SCAO Module is located inside the cryogenic environment of METIS and hosts a pyramid type wavefront sensor, operating in the near-infrared. The wavefront control loop, as well as a number of secondary control tasks, will be realized within the SCAO Control System. This paper outlines on the PDR design of METIS SCAO. © 2019 AO4ELT 2019 - Proceedings 6th Adaptive Optics for Extremely Large Telescopes. All rights reserved

The Euclid near-infrared calibration source

The Euclid dark energy mission is currently competing in ESA's Cosmic Vision program. Its imaging instrument, which has one visible and one infrared channel, will survey the entire extragalactic sky during the 5 year mission. The near-infrared imaging photometer (NIP) channel, operating in the ~0.92 - 2.0 μm spectral range, will be used in conjunction with the visible imaging channel (VIS) to constrain the nature of dark energy and dark matter. To meet the stringent overall photometric requirement, the NIP channel requires a dedicated on-board flat-field source to calibrate the large, 18 detector focal plane. In the baseline concept a 170 mm Spectralon diffuser plate, mounted to a pre-existing shutter mechanism outside the channel, is used as a flat-field calibration target, negating the need for an additional single-point-failure mechanism. The 117 × 230 mm focal plane will therefore be illuminated through all of the channel's optical elements and will allow flat-field measurements to be taken in all wavelength bands. A ring of low power tungsten lamps, with custom reflecting elements optimized for optical performance, will be used to illuminate the diffuser plate. This paper details the end-to-end optical simulations of this concept, a potential mechanical implementation and the initial tests of the proposed key components