David Lunney

Harps-N: the new planet hunter at TNG

The Telescopio Nazionale Galileo (TNG)[9] hosts, starting in April 2012, the visible spectrograph HARPS-N. It is based on the design of its predecessor working at ESOs 3.6m telescope, achieving unprecedented results on radial velocity measurements of extrasolar planetary systems. The spectrographs ultra-stable environment, in a temperature-controlled vacuum chamber, will allow measurements under 1 m/s which will enable the characterization of rocky, Earth-like planets. Enhancements from the original HARPS include better scrambling using octagonal section fibers with a shorter length, as well as a native tip-tilt system to increase image sharpness, and an integrated pipeline providing a complete set of parameters. Observations in the Kepler field will be the main goal of HARPS-N, and a substantial fraction of TNG observing time will be devoted to this follow-up. The operation process of the observatory has been updated, from scheduling constraints to telescope control system. Here we describe the entire instrument, along with the results from the first technical commissioning.

Space-quality data from balloon-borne telescopes: the High Altitude Lensing Observatory (HALO)

We present a method for attaining sub-arcsecond pointing stability during sub-orbital balloon flights, as designed for in the High Altitude Lensing Observatory (HALO) concept. The pointing method presented here has the potential to perform near-space quality optical astronomical imaging at similar to 1-2% of the cost of space-based missions. We also discuss an architecture that can achieve sufficient thermo-mechanical stability to match the pointing stability. This concept is motivated by advances in the development and testing of Ultra Long Duration Balloon (ULDB) flights which promise to allow observation campaigns lasting more than three months. The design incorporates a multi-stage pointing architecture comprising: a gondola coarse azimuth control system, a multi-axis nested gimbal frame structure with arcsecond stability, a telescope de-rotator to eliminate field rotation, and a fine guidance stage consisting of both a telescope mounted angular rate sensor and guide CCDs in the focal plane to drive a Fast-Steering Mirror. We discuss the results of pointing tests together with a preliminary thermo-mechanical analysis required for sub-arcsecond pointing at high altitude. Possible future applications in the areas of wide-field surveys and exoplanet searches are also discussed

Design status of WFCAM: a wide-field camera for the UK Infrared Telescope

An update on the design status of the UKIRT Wide Field Camera (WFCAM) is presented. WFCAM is a wide field infrared camera for the UK Infrared Telescope, designed to produce large scale infrared surveys. The complete system consists of a new IR camera with integral autoguider and a new tip/tilt secondary mirror unit. WFCAM is being designed and built by a team at the UK Astronomy Technology Centre in Edinburgh, supported by the Joint Astronomy Centre in Hawaii. The camera uses a novel quasi-Schmidt camera type design, with the camera mounted above the UKIRT primary mirror. The optical system operates over 0.7 - 2.4 μm and has a large corrected field of view of 0.9° diameter. The focal plane is sparsely populated with 4 2K x 2K Rockwell HAWAII-2 MCT array detectors, giving a pixel scale of 0.4 arcsec/pixel. A separate autoguider CCD is integrated into the focal plane unit. Parallel detector controllers are used, one for each of the four IR arrays and a fifth for the autoguider CCD.

HARMONI: a single-field wide-band integral-field spectrograph for the European ELT

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-ELTs 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].

HARMONI: the first light integral field spectrograph for the E-ELT

HARMONI is a visible and near-infrared (0.47 to 2.45 μm) integral field spectrometer, providing the E-ELTs core spectroscopic capability, over a range of resolving powers from R (≡λ/Δλ)~500 to R~20000. The instrument provides simultaneous spectra of ~32000 spaxels at visible and near-IR wavelengths, arranged in a √2:1 aspect ratio contiguous field. HARMONI is conceived as a workhorse instrument, addressing many of the E-ELT’s key science cases, and will exploit the E-ELTs scientific potential in its early years, starting at first light. HARMONI provides a range of spatial pixel (spaxel) scales and spectral resolving powers, which permit the user to optimally configure the instrument for a wide range of science programs; from ultra-sensitive to diffraction limited, spatially resolved, physical (via morphology), chemical (via abundances and line ratios) and kinematic (via line-of-sight velocities) studies of astrophysical sources. Recently, the HARMONI design has undergone substantial changes due to significant modifications to the interface with the telescope and the architecture of the E-ELT Nasmyth platform. We present an overview of the capabilities of HARMONI, and of its design from a functional and performance viewpoint.

SCUBA-2: Engineering and Commissioning Challenges of the World's Largest sub-mm Instrument at the JCMT

Over preceding conferences, the design and implementation of the SCUBA-2 (Sub-millimeter Common-User Bolometric Array 2) instrument hardware has been described in detail. SCUBA-2 has been installed on the James Clerk Maxwell Telescope (JCMT) for over two years and its hardware has been successfully commissioned. This paper describes the culmination of this process and compares the optical/mechanical design and test expectations of the instrument hardware against the performance achieved in the field.

Precision radial velocity spectrograph

We present a conceptual design for a Precision Radial Velocity Spectrograph (PRVS) for the Gemini telescope. PRVS is a fibre fed high resolving power (R~70,000 at 2.5 pixel sampling) cryogenic echelle spectrograph operating in the near infrared (0.95 - 1.8 microns) and is designed to provide 1 m/s radial velocity measurements. We identify the various error sources to overcome in order to the required stability. We have constructed models simulating likely candidates and demonstrated the ability to recover exoplanetary RV signals in the infrared. PRVS should achieve a total RV error of around 1 m/s on a typical M6V star. We use these results as an input to a simulated 5-year survey of nearby M stars. Based on a scaling of optical results, such a survey has the sensitivity to detect several terrestrial mass planets in the habitable zone around nearby stars. PRVS will thus test theoretical planet formation models, which predict an abundance of terrestrial-mass planets around low-mass stars.We have conducted limited experiments with a brass-board instrument on the Sun in the infrared to explore real-world issues achieving better than 10 m/s precision in single 10 s exposures and better than 5 m/s when integrated across a minute of observing.

Automatic setup of SCUBA-2 detector arrays

The detector arrays for the SCUBA-2 instrument consist of TES bolometers with superconducting amplifier and multiplexing circuits based on Superconducting Quantum Interference Devices (SQUIDs). The SCUBA-2 TES arrays and their multiplexed SQUID readouts need to be set-up carefully to achieve correct performance. Algorithms have been developed and implemented based on the first available commissioning grade detector, enabling the array to be set up and optimized automatically.

Configuration of readout electronics and data acquisition for the HiPERCAM instrument

HiPERCAM is a five channel fast photometer to study high temporal variability of the universe, covering from 0.3 to 1.0 microns in five wavebands. HiPERCAM uses custom-made 2Kx1K split-frame transfer CCDs mounted in separate compact camera heads and cooled by thermoelectric coolers to 180K. The demands on the readout system are very unique to this instrument in that all five CCDs are operated in a pseudo drift window mode along with the normal windowing, binning and full-frame modes. The pseudo drift mode involves reading out small window regions from 2 quadrants of each CCD, with the possibility to exceed 1 kHz window rates per output channel. The CCDs are custom manufactured by Teledyne e2v to allow independent serial clock controls for each output. The devices are manufactured in standard and deep-depletion processes with appropriate anti-reflection coatings to achieve high quantum efficiencies in each of the five wavebands. An ESO NGC controller has been configured to control and readout all five CCDs. The data acquisition software has been modified to provide GPS timestamping of the data and access to the acquired data in real time for the data reduction software. The instrument has had its first light and first science observations on the 4.2m William Herschel Telescope, La Palma during a commissioning run in October 2017 and subsequently on the 10.4m Gran Telescopio Canarias in February 2018 and science observations in April 2018. This paper will present the details of the preamplifier electronics, configuration of the readout electronics and the data acquisition software to support the unique readout modes along with the overall performance of the instrument.

NIX, the imager for ERIS: the AO instrument for the VLT

ERIS will be the next-generation AO facility on the VLT, combining the heritage of NACO imaging, with the spectroscopic capabilities of an upgraded SINFONI. Here we report on the all-new NIX imager that will deliver diffraction-limited imaging from the J to M band. The instrument will be equipped with both Apodizing Phase Plates and Sparse Aperture Masks to provide high-angular resolution imagery, especially suited for exoplanet imaging and characterization. This paper provides detail on the instrument’s design and how it is suited to address a broad range of science cases, from detailed studies of the galactic centre at the highest resolutions, to studying detailed resolved stellar populations.