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The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) is an integral field spectrograph (IFS) that has been built for the Subaru telescope. CHARIS has two imaging modes; the high-resolution mode is R82, R69, and R82 in J, H, and K bands respectively while the low-resolution discovery mode uses a second low-resolution prism with R19 spanning 1.15-2.37 microns (J+H+K bands). The discovery mode is meant to augment the low inner working angle of the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) adaptive optics system, which feeds CHARIS a coronagraphic image. The goal is to detect and characterize brown dwarfs and hot Jovian planets down to contrasts five orders of magnitude dimmer than their parent star at an inner working angle as low as 80 milliarcseconds. CHARIS constrains spectral crosstalk through several key aspects of the optical design. Additionally, the repeatability of alignment of certain optical components is critical to the calibrations required for the data pipeline. Specifically the relative alignment of the lens let array, prism, and detector must be highly stable and repeatable between imaging modes. We report on the measured repeatability and stability of these mechanisms, measurements of spectral crosstalk in the instrument, and the propagation of these errors through the data pipeline. Another key design feature of CHARIS is the prism, which pairs Barium Fluoride with Ohara L-BBH2 high index glass. The dispersion of the prism is significantly more uniform than other glass choices, and the CHARIS prisms represent the first NIR astronomical instrument that uses L-BBH2as the high index material. This material choice was key to the utility of the discovery mode, so significant efforts were put into cryogenic characterization of the material. The final performance of the prism assemblies in their operating environment is described in detail. The spectrograph is going through final alignment, cryogenic cycling, and is being delivered to the Subaru telescope in April 2016. This paper is a report on the laboratory performance of the spectrograph, and its current status in the commissioning process so that observers will better understand the instrument capabilities. We will also discuss the lessons learned during the testing process and their impact on future high-contrast imaging spectrographs for wavefront control.

The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) is an integral field spectrograph (IFS) being built for the Subaru telescope. CHARIS will take spectra of brown dwarfs and hot Jovian planets in the coronagraphic image provided by the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) and AO188 adaptive optics systems. 1, 2 The system is designed to detect objects five orders of magnitude dimmer than their parent star down to an 80 milliarcsecond inner working angle. For characterization, CHARIS has a high-resolution prism providing an average spectral resolution of R82, R69, and R82 in J, H, and K bands respectively. The so-called discovery mode uses a second low-resolution prism with an average spectral resolution of R19 spanning 1.15-2.37 microns (J+H+K bands). This is unique compared to other high contrast IFS designs. It augments low inner working angle performance by reducing the separation at which we can rely on spectral differential imaging. The principal challenge for a high-contrast IFS is quasi-static speckles, which cause undue levels of spectral crosstalk. CHARIS has addressed this through several key design aspects that should constrain crosstalk between adjacent spectral features to be below 1%. Sitting on the Nasmyth platform, the alignment between the lenslet array, prism, and detector will be highly stable, key for the performance of the data pipeline. Nearly every component has arrived and the project is entering its final build phase. Here we review the science case, the resulting design, status of final construction, and lessons learned that are directly applicable to future exoplanet instruments.

Current AO observations rely heavily on the AO188 instrument, a 188-elements system that can operate in natural or laser guide star (LGS) mode, and delivers diffraction-limited images in near-IR. In its LGS mode, laser light is transported from the solid state laser to the launch telescope by a single mode fiber. AO188 can feed several instruments: the infrared camera and spectrograph (IRCS), a high contrast imaging instrument (HiCIAO) or an optical integral field spectrograph (Kyoto-3DII). Adaptive optics development in support of exoplanet observations has been and continues to be very active. The Subaru Coronagraphic Extreme-AO (SCExAO) system, which combines extreme-AO correction with advanced coronagraphy, is in the commissioning phase, and will greatly increase Subaru Telescope’s ability to image and study exoplanets. SCExAO currently feeds light to HiCIAO, and will soon be combined with the CHARIS integral field spectrograph and the fast frame MKIDs exoplanet camera, which have both been specifically designed for high contrast imaging. SCExAO also feeds two visible-light single pupil interferometers: VAMPIRES and FIRST. In parallel to these direct imaging activities, a near-IR high precision spectrograph (IRD) is under development for observing exoplanets with the radial velocity technique. Wide-field adaptive optics techniques are also being pursued. The RAVEN multi-object adaptive optics instrument was installed on Subaru telescope in early 2014. Subaru Telescope is also planning wide field imaging with ground-layer AO with the ULTIMATE-Subaru project.

Princeton University is building the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), an integral field spectrograph (IFS) for the Subaru telescope. CHARIS is funded by the National Astronomical Observatory of Japan and is designed to take high contrast spectra of brown dwarfs and hot Jovian planets in the coronagraphic image provided by the Coronagraphic Extreme Adaptive Optics (SCExAO) and the AO188 adaptive optics systems. The project is now in the build and test phase at Princeton University. Once laboratory testing has been completed CHARIS will be integrated with SCExAO and AO188 in the winter of 2016. CHARIS has a high-resolution characterization mode in J, H, and K bands. The average spectral resolution in J, H, and K bands are R82, R68, and R82 respectively, the uniformity of which is a direct result of a new high index material, L-BBH2. CHARIS also has a second low-resolution imaging mode that spans J,H, and K bands with an average spectral resolution of R19, a feature unique to this instrument. The field of view in both imaging modes is 2.07x2.07 arcseconds. SCExAO+CHARIS will detect objects five orders of magnitude dimmer than their parent star down to an 80 milliarcsecond inner working angle. The primary challenge with exoplanet imaging is the presence of quasi-static speckles in the coronagraphic image. SCExAO has a wavefront control system to suppress these speckles and CHARIS will address their impact on spectral crosstalk through hardware design, which drives its optical and mechanical design. CHARIS constrains crosstalk to be below 1% for an adjacent source that is a full order of magnitude brighter than the neighboring spectra. Since CHARIS is on the Nasmyth platform, the optical alignment between the lenslet array and prism is highly stable. This improves the stability of the spectra and their orientation on the detector and results in greater stability in the wavelength solution for the data pipeline. This means less uncertainty in the post-processing and less overhead for on-sky calibration procedures required by the data pipeline. Here we present the science case, design, and construction status of CHARIS. The design and lessons learned from testing CHARIS highlights the choices that must be considered to design an IFS for high signal-to-noise spectra in a coronagraphic image. The design considerations and lessons learned are directly applicable to future exoplanet instrumentation for extremely large telescopes and space observatories capable of detecting rocky planets in the habitable zone.

We report the current status of the Infrared Doppler (IRD) instrument for the Subaru telescope, which aims at detecting Earth-like planets around nearby M darwfs via the radial velocity (RV) measurements. IRD is a fiber-fed, near infrared spectrometer which enables us to obtain high-resolution spectrum (R~70000) from 0.97 to 1.75 μm. We have been developing new technologies to achieve 1m/s RV measurement precision, including an original laser frequency comb as an extremely stable wavelength standard in the near infrared. To achieve ultimate thermal stability, very low thermal expansion ceramic is used for most of the optical components including the optical bench.

ERIS is an image simulator for CHARIS, the high-contrast exoplanet integral field spectrograph (IFS) being built at Princeton University for the Subaru telescope. We present here the software design and implementation of the ERIS code. ERIS simulates CHARIS FITS images and data cubes that are used for developing the data reduction pipeline and verifying the expected CHARIS performance. Components of the software include detailed models of the light source (such as a star or exoplanet), atmosphere, telescope, adaptive optics systems (AO188 and SCExAO), CHARIS IFS and the Hawaii2-RG infrared detector. Code includes novel details such as the phase errors at the lenslet array, optical wavefront error maps and pinholes for reducing crosstalk, just to list a few. The details of the code as well as several simulated images are presented in this paper. This IFS simulator is critical for the CHARIS data analysis pipeline development, minimizing troubleshooting in the lab and on-sky and the characterization of crosstalk.

Princeton University is building an integral field spectrograph (IFS), the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), for integration with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system and the AO188 adaptive optics system on the Subaru telescope. CHARIS and SCExAO will measure spectra of hot, young Jovian planets in a coronagraphic image across J, H, and K bands down to an 80 milliarcsecond inner working angle. SCExAO’s coronagraphs and wavefront control system will make it possible to detect companions five orders of magnitude dimmer than their parent star. However, quasi-static speckles in the image contaminate the signal from the planet. In an IFS this also causes uncertainty in the spectra due to diffractive cross-contamination, commonly referred to as crosstalk. Post-processing techniques can subtract these speckles, but they can potentially skew spectral measurements, become less effective at small angular separation, and at best can only reduce the crosstalk down to the photon noise limit of the contaminating signal. CHARIS will address crosstalk effects of a high contrast image through hardware design, which drives the optical and mechanical design of the assembly. The work presented here sheds light on the optical and mechanical considerations taken in designing the IFS to provide high signal-to-noise spectra in a coronagraphic image from and extreme adaptive optics image. The design considerations and lessons learned are directly applicable to future exoplanet instrumentation for extremely large telescopes and space observatories capable of detecting rocky planets in the habitable zone.

Polarization optical particle counter (POPC) capable of measuring particle shape or sphericity was developed, which uses detection of polarization of light scattered by particles. Sensors that detected P and S polarization components are incorporated at scattering angle of 120˚ in addition to ordinary sensor located at the angle of 60˚. The particle size is derived from the pulse height detected with the ordinary sensor. The size thresholds were determined by measurements of PSL standard particles. Polarization of particle is calculated as the ratio of S polarization component to the sum of all components. The POPC field observations were started in Fukuoka, Japan on 15 March 2012 and in Matsue, Japan on 28 February 2012. Air pollution with high particle number concentration was observed in Fukuoka on 11 April. In that time, the particles with polarization lower than 0.3 constituted 90% of particles in the size range from 0.5 µm to 3 µm and 70-90% of those from 3 µm to 5 µm. Most of the atmospheric aerosol particles were consisted of spherical particles. Significant Asian dust transport was observed in Fukuoka on from 31 March to 1 April. The particles with polarization lower than 0.3 constituted 80% of those from 0.5 µm to 1 µm, 55-65% of those from 1 µm to 5µm. The increase of the ratio of non-spherical particles to all particles in Asian dust event was confirmed. The POPC thus is capable of measuring particle shape as well as size for each individual particle.

IRD is the near-infrared high-precision radial velocity instrument for the Subaru 8.2-m telescope. It is a relatively compact (~1m size) spectrometer with a new echelle-grating and Volume-Phase Holographic gratings covering 1-2 micron wavelengths combined with an original frequency comb using optical pulse synthesizer. The spectrometer will employ a 4096x4096-pixel HgCdTe array under testing at IfA, University of Hawaii. Both the telescope/Adaptive Optics and comb beams are fed to the spectrometer via optical fibers, while the instrument is placed at the Nasmyth platform of the Subaru telescope. Expected accuracy of the Doppler-shifted velocity measurements is about 1 m s-1. Helped with the large collecting area and high image quality of the Subaru telescope, IRD can conduct systematic radial velocity surveys of nearby middle-to-late M stars aiming for down to one Earth-mass planet. Systematic observational and theoretical studies of M stars and their planets for the IRD science are also ongoing. We will report the design and preliminary development progresses of the whole and each component of IRD.

The High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO), is a coronographic simultaneous differential imager for the new 188-actuator AO system at the Subaru Telescope Nasmyth focus. It is designed primarily to search for faint companions, brown dwarves and young giant planets around nearby stars, but will also allow observations of disks around young stars and of emission line regions near other bright central sources. HiCIAO will work in conjunction with the new Subaru Telescope 188-actuator adaptive optics system. It is designed as a flexible, experimental instrument that will grow from the initial, simple coronographic system into more complex, innovative optics as these technologies become available. The main component of HiCIAO is an infrared camera optimized for spectral simultaneous differential imaging that uses a Teledyne 2.5 μm HAWAII-2RG detector array operated by a Sidecar ASIC. This paper reports on the assembly, testing, and "first light" observations at the Subaru Telescope.

Direct exploration of exoplanets is one of the most exciting topics in astronomy. Our current efforts in this field are concentrated on the Subaru 8.2m telescope at Mauna Kea, Hawaii. Making use of the good observing site and the excellent image quality, the infrared coronagraph CIAO (Coronagraphic Imager with Adaptive Optics) has been used for various kinds of surveys, which is the first dedicated cold coronagraph on the 8-10m class telescopes. However, its contrast is limited by the low-order adaptive optics and a limited suppression of the halo speckle noise. HiCIAO is a new high-contrast instrument for the Subaru telescope. HiCIAO will be used in conjunction with the new adaptive optics system (188 actuators and/or its laser guide star - AO188/LGSAO188) at the Subaru infrared Nasmyth platform. It is designed as a flexible camera comprising several modules that can be configured into different modes of operation. The main modules are the AO module with its future extreme AO capability, the warm coronagraph module, and the cold infrared camera module. HiCIAO can combine coronagraphic techniques with either polarization or spectral simultaneous differential imaging modes. The basic concept of such differential imaging is to split up the image into two or more images, and then use either different planes of polarization or different spectral filter band-passes to produce a signal that distinguishes faint objects near a bright central object from scattered halo or residual speckles. In this contribution, we will outline the HiCIAO instrument, its science, and performance simulations. The optical and mechanical details are described by Hodapp et al. (2006)1. We also present a roadmap of Japanese facilities and future plans, including ASTRO-F (AKARI), SPICA, and JTPF, for extrasolar planet explorations.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Lidar observations of stratospheric aerosols have been performed at Ny-Aalesund (79 degrees N, 12 degrees East), Svalbard every winter since January 1994. We detected many PSC events in the stratosphere under low temperature condition, especially in 1994/95, 1995/96, 1996/97 winter campaigns. Meanwhile in the Antarctic, lidar observations were made from April, 1997 to January, 1998 at Dome Fuji (78 degrees South, 40 degrees East), and many PSCs were detected almost every day from the end of May to mid October. In the Arctic, PSC layers at the initial stage of appearance were composed mainly of solid particles in each winter season and the layers at sufficiently low temperatures were composed of spherical particles. In the Antarctic, PSCs similar to those over Ny- Aalesund were also detected frequently while the polar vortex was developing or the vortex was unstable. But after a remarkable decrease in the temperature by the invasion of blocking high into the polar vortex, PSCs detected were mainly composed of solid particles.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Lidar and Optical Particle Counter (OPC) measurements were performed in the Canadian Arctic and in the Indonesian Tropical region. The observations yielded very interesting and important results about the features of the latitudinal difference in the stratospheric aerosols. Besides the latitudinal difference, the aerosol distributions and their time variation showed unique characteristics in each of the regions. In Arctic winter, the aerosol concentration varies frequently day-to-day. In the Tropical region, the aerosol distribution and the vertical transport is, probably, controlled by the variation of the circulation pattern in the lower stratosphere related to the QBO in the tropical stratosphere. Based on the results of the simultaneous measurements by lidar and OPCs, we estimated surface area density, volume density, S-parameter (extinction to backscatter ratio), backscatter to surface area conversion factor, and backscatter to volume conversion factor of the stratospheric aerosols at 20km-altitude in the Arctic and Tropical regions.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

For the study of stratospheric aerosol over the Tropics, balloon-borne OPC measurements have been made six times from April 1997 to March 2000 at Bandung, Indonesia (6.9?S, 107.6?E) where Lidar measurements have also been made since early 1997. Correlative measurements of Lidar and OPC were conducted on March 25,1998 and August 23, 1999. Results of the latter measurement were compared in this paper. The profile of back scattering ratio measured by Lidar almost represents a vertical distribution of small particles having radii smaller than O.4?m. We calculated back scattering coefficients from the results of OPC measurement. The calculated and measured back scattering coefficients were not consistent completely but not so unreasonable.

A comparative measurement of the free tropospheric aerosol particles using a ground-based Raman lidar and in-situ sampling instruments on board an aircraft was made over central part of Japan (35-36°N, 136-137°E) in the Asian dust period on April 23, 1996. We compared the aerosol properties measured with the lidar (aerosol backscattering coefficients and the depolarization ratio at the wavelength of 532 nm) and those obtained with the aircraft-based instruments (aerosol shape and surface feature, number size distribution, and chemical composition). The aerosol backscattering coefficients calculated from the aerosol size distribution obtained with the airborne optical particle counters (OPCs) showed good agreements (mean relative difference of 22%) with those measured with the lidar above the altitude of 3.1 km, but showed large difference (mean relative difference of 50%) below 3.1 km. The aerosol depolarization ratios correlated well with the fractions of the backscattering coefficient of the coarse mode particles (radius>0.5 μm) in the total aerosol backscattering coefficient calculated from the OPCs data above 3.4 km. This suggests that the coarse mode particles that consisted mainly of nonspherical mineral dust particles predominantly contributed the depolarized signals in this altitude region. The aerosol depolarization ratio of the coarse mode particles was estimated to be 164% at 5.3 km.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Subaru Telescope of National Astronomical Observatory of Japan is now finishing the commissioning of telescope and instruments at the summit of Mauna Kea, Hawaii. There will be an announcement for open usage in near future. The proposal management system of the Subaru Telescope (PMSS) which accept and retrieve proposals for open use of the Subaru Telescope is now constructed on the Subaru Telescope Network, the super computer system of the Subaru Telescope. The PMSS is developed on the object oriented data model, a Use Case Model, and a prototyping has been completed.

This article describes results of the first light observations of the Orion nebular an dL1551 IRS 5 carried out with the Subaru telescope in January 1999. The new RI images of the Orion nebula, taken under the seeing conditions of 0.2 inch-0.5 inch, cover the area of 5 by 5 feet centered on the Trapezium cluster, revealing details of the BN/KL region, the bright bar, and other conspicuous features as well as several new H 2 emission sources. There are more than 500 stars detected; most of them are not visible in optical images and are embedded in the molecular cloud behind the nebula. Their K'-band luminosity function confirmed the bump around 12 mag with a tail toward the fainter end of 17 mag. Some of these most faint stars may be good candidates for young brown dwarfs. The J-band image of L1551 IRS 5 revealed a pair of twisted jets emanating possibly from each of the binary protostars. The two jets are spatially resolved for the first time from the ground, with wiggly and knotty appearance similar to the R-band image taken with the Hubble Space Telescope, suggesting that the appearance is intrinsic to them and is not caused due to the spatial variation of extinction. Successive grism spectroscopy proved that the jet emission predominantly arises from the (Fe II) lines.

The Subaru Telescope introduces a tip-tilt and chopping mechanism for an JR secondary mirror, which is of ULE lightweight type, 1.3m in diameter and 180kg in weight. Performance targets of the tip-tilt and chopping mechanism are 30Hzcontrol band width with 0.01" resolution for tip-tilt and 30" amplitude with frequency of 5Hz for chopping. To archivethese targets, a system combining 6-point dynamic drive mechanism and 15-point passive support mechanism against forgravity are developed and compact actuators of electric magnet type for the drive mechanism are employed. Test with adummy mirror shows that the performance target are achieved. This paper describes the design and test results of the tip-tilt and chopping mechanism.Keywords : chopping secondary, tip-tilt, tracking. 1. INTRODUCTION The Subaru Telescope introduces a tip-tilt and chopping mechanism for Infrared (IR) secondary mirror, which is of ULElight weight type, 1.3m in diameter and 180kg in weight. Performance targets of the tip-tilt and chopping mechanism are30Hz control band width with 0.01" resolution for tip-tilt and 30" amplitude with frequency of 5Hz for chopping.To achieve these performance targets with a large glass secondary mirror as that for the Subaru Telescope, there arefollowing difficulties:( 1) Combination between drive mechanism and passive supports.For the 1.3m glass mirror tip-tilt/chopping, both functions of 10-15 points passive support and dynamic driveare necessary simultaneously.(2) Large drive forceDue to the mass of the secondary mirror, large drive force is necessary.(3) Control band widthDue to the resonant frequency of the secondary mirror, the control band width is limited.To dissolve (1), a fluid whiffle tree type passive support which keeps constant passive supporting force against for thesecondary mirror tilt has been developped. For (2), compact electromagnetic actuator has been developped. For (3), multipoints (6points) dynamic drive system has been introduced.