During the past year, the Multi-Object InfraRed Camera and Spectrograph at Subaru has undergone an upgrade of its science detectors, the housekeeping electronics and the instrument control software. This overhaul aims at increasing MOIRCS' sensitivity, observing efficiency and stability. Here we present the installation and the alignment procedure of the two Hawaii 2RG detectors and the design of a cryogenic focus mechanism. The new detectors show significantly lower read noise, increased quantum efficiency, and lower the readout time.
In 2014 and 2015 the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) instrument at the Subaru Telescope on Maunakea is underwent a significant modernization and upgrade project. We upgraded the two Hawaii2 detectors to Hawaii2-RG models, modernized the cryogenic temperature control system, and rewrote much of the instrument control software. The detector upgrade replaced the Hawaii2 detectors which use the Tohoku University Focal Plane Array Controller (TUFPAC) electronics with Hawaii2-RG detectors using SIDECAR ASIC (a fully integrated FPA controller system-on-a-chip) and a SAM interface card. We achieved an improvement in read noise by a factor of about 2 with this detector and electronics upgrade. The cryogenic temperature control upgrade focused on modernizing the components and making the procedures for warm up and cool down of the instrument safer. We have moved PID control loops out of the instrument control software and into Lakeshore model 336 cryogenic temperature controllers and have added interlocks on the warming systems to prevent overheating of the instrument. Much of the instrument control software has also been re-written. This was necessitated by the different interface to the detector electronics (ASIC and SAM vs. TUFPAC) and by the desire to modernize the interface to the telescope control software which has been updated to Subaru's "Gen2" system since the time of MOIRCS construction and first light. The new software is also designed to increase reliability of operation of the instrument, decrease overheads, and be easier for night time operators and support astronomers to use.
A future plan for the next-generation Subaru adaptive optics, is a system based on an adaptive secondary mirror. A ground-layer adaptive optics combined with a new wide-field multi-object infrared camera and spectrograph will be a main application of the adaptive secondary mirror. A preliminary simulation results show that the resolution achieved by the ground-layer adaptive optics is expected to be better than 0.2 arcsecond in the K-band over 15 arcminutes field-of-view. In this paper, the performance simulation is updated taking dependence on observation conditions, the zenith angle and the season, into account.
A wide-field adaptive optics system based on an adaptive secondary mirror (ASM) is one of a future plan for
the next-generation Subaru adaptive optics system. The main application of ASM based AO will be a groundlayer
adaptive optics (GLAO) with field-of-view larger than 10 arc minutes. The high Strehl-ratio of on-source correction by high-order ASM (expected to be about 1000) and the reduction of emissivity are also attractive points. In this paper, we report a preliminary result of simulations for the these applications of ASM to study conceptual design of the next-generation wide-field Subaru adaptive optics.
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.
An infrared instrument used for observation has to keep the detector and optical components in a very cold environment
during operation. However, because of maintenance, upgrades, and other routine work, there are situations that require
the instrument to be warmed-up and then cooled-down again. At Subaru Observatory, our MOIRCS infrared instrument
has required warm-up and cool-down several times a year for routine maintenance and filter replacement. The MOIRCS
instrument has a large heat capacity and cool-down using only the closed cycle cooler is impractical due to the huge
amount of time it would require. To address this problem Subaru engineers have created a mechanism to allow PRE-COOLING
of the instrument via liquid nitrogen - allowing for a much faster pre-cool process. Even with liquid nitrogen,
the pre-cool process requires 10 tanks and almost a week of continual monitoring in order to reach the desired target
temperature. It is very difficult to work for such a long period of time at the oxygen starved summit of Mauna Kea (4205
meters),and issues of man-power and scheduling conflicts only add to the problems. To address these concerns Subaru
developed an automated pre-cooling system which works continuously and remotely at the summit. The strategy was to
have basic functionality for pre-cooling and user friendly interface. i.e. (1) Continuous cooling until the target
temperature is reached by automated liquid nitrogen tank exchanges and precision temperature control by automated
changes to the liquid nitrogen flow. (2) Remote monitoring and control of all parameter setting by Web browser as user
interface (UI). The goal of the Subaru pre-cooling system was to make it both inexpensive and quick to implement by
using existing technologies. The original goal (to cut down on labor and precision temperature control) has been attained
through several pre-cooling and software/hardware modification cycles. We will report on the progress and status of our
pre-cooling experiences in this presentation.
To study properties of cold dark matter (CDM), which can only be observed through its gravitational interaction
with galaxies, spatially resolved spectra at least to the K-band are desirable. We started designing a spectrograph
which observes multiple targets spatially resolved in a telescope field of view fed with multi-object adaptive
optics (MOAO). The current design either places field lenses on the telescope field of view to image the pupil
onto steering mirrors, or uses a single set of field lens to deliver beams to pick-off arms. The steering mirror on
the pupil image tilts and selects a sub-field from each of the telescope field of view physically split by the field
lenses. This allows cheaper and more robust construction of a method to select the target fields with a limitation
in selections of the target fields. On the other hand, the pick-off arm implementation allows more flexibility
in assigning targets to fields of the integral field units (IFUs) especially when targets are clustered. The IFU
arranges spatial elements of each of sub-field of view to be fed into the spectrograph. If enough pixels are afforded,
using microlens arrays, which image pupils of spatial elements onto the object plane of the spectrograph is ideal
in robustness. Otherwise, an image slicer is to be located to arrange the sub-field of view onto the entrance slit.
The instrument should be built as modules to allow expeditious scientific results.
As the construction of the Subaru Telescope neared the end and the preparation of the first aluminum coating of the primary mirror on the ground floor of the telescope enclosure was in progress in 1997, dust particles blown into the enclosure became a serious issue. The source of the dust particles was mainly volcano cinder rocks in the immediate vicinity of the dome that were crushed through the construction activities, especially by heavy vehicle traffic around the dome. The mitigation measure proposed was to pave the immediate surrounding of the dome. The Subaru dome has a unique design with the special consideration to the airflow through the structure with a few ventilators for the best seeing condition possible. The heat retained by the pavement that may possibly cause thermals was an immediate concern. We examined several types of pavement materials to solve this problem and decided the most suitable materials and method. As a result, we paved the area using asphalt, and were able to improve seeing performance before midnight observation by painting the surface of pavement area white in 2003.
Subaru Telescope has been in operation for open use for six years. As the first-generation instruments became all operational and as minimal engineering time has been spent for the commissioning of the second-generation instrument, science time counts over 80% of the total telescope time since 2002. Downtime is almost minimized thanks to the stability of the telescope and the instruments and to the dedication of the support staff. Due to overwhelming deficiency in national budget of Japan, Subaru Telescope faces more serious budget cut than expected. This paper presents how the observatory is/will be dealing with the reduced budget with minimum impact to the operation that may pose observers any restriction to use the 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.
The design, development, operation and current performance of MOS (multi-object spectroscopy) mode of MOIRCS is described. MOIRCS (Multi-Object Infrared Camera and Spectrograph) is one of the second-generation instruments for the Subaru Telescope and provides imaging and MOS modes with a 4' × 7' field of view for a wavelength range from 0.85 to 2.5 μm. To achieve near-infrared (NIR) MOS up to K-band, MOS mode uses multi-slit masks and a mask exchange system in a cryogenic environment. The masks are housed in a vacuum dewar attached to the MOIRCS main dewar and separated by a large gate valve. The mask dewar is equipped with its own cryogenic cooler and a vacuum pump and is capable of storing eighteen masks. The masks are made of thin aluminum foil. Slits are cut with a laser, with software that corrects for the effects of thermal contraction. The masks are cooled to below 130 K in the mask dewar and transported to the focal plane in the main dewar through the gate valve with a linear motion manipulator. An interlock is equipped on the mask exchange system to secure the cryogenic instrument from accident. Replacing masks can be done in the daytime without breaking the vacuum of the main dewar by isolating the mask dewar with the gate valve. Acquisition occurs by iteratively taking on-sky images through alignment holes on the mask until the rotation and offset between alignment stars and alignment holes become small enough. MOIRCS/MOS mode will be open to the public in late 2006.
MOIRCS is a new Cassegrain instrument of Subaru telescope, dedicated for wide field imaging and multi-object spectroscopy in near-infrared. MOIRCS has been constructed jointly by Tohoku University and the Subaru Telescope and saw the first light in Sept., 2004. The commissioning observations to study both imaging and spectroscopic performance were conducted for about one year. MOIRCS mounts two 2048 × 2048 HAWAII2 arrays and provides a field of view of 4' x 7' with a pixel scale of 0."117. All-lens optical design is optimized for 0.8 to 2.5 μm with no practical chromatic aberration. Observations confirm the high image quality over the field of view without any perceptible degradation even at the field edge. The best seeing we have obtained so far is FWHM=0."18. A novel design of MOIRCS enables us to perform multi-object spectroscopy with aluminum slit masks, which are housed in a carrousel dewar and cooled to ~ 110 K. When choosing MOS mode, a manipulator pulls out a slit mask from the carrousel into the MOIRCS main dewar and sets it properly at the Cassegrain focus. The carrousel is shuttered by a gate valve, so that it can be warmed and cooled independently to exchange slit-mask sets during daytime. We have tested various configurations of 30 or more multi-slit positions in various sky fields and found that targets are dropped at the centers of slits or guide holes within a dispersion of about 0.3 pixels (0."03). MOIRCS has been open to common use specifically for imaging observations since Feb. 2006. The MOS function will be available in next August.
MOIRCS (Multi-Object Infrared Camera and Spectrograph) is a new instrument for the Subaru telescope. In order to perform observations of near-infrared imaging and spectroscopy with cold slit mask, MOIRCS contains many device components, which are distributed on an Ethernet LAN. Two PCs wired to the focal plane array electronics operate two HAWAII2 detectors, respectively, and other two PCs are used for integrated control and quick data reduction, respectively. Though most of the devices (e.g., filter and grism turrets, slit exchange mechanism for spectroscopy) are controlled via RS232C interface, they are accessible from TCP/IP connection using TCP/IP to RS232C converters. Moreover, other devices are also connected to the Ethernet LAN. This network distributed structure provides flexibility of hardware configuration. We have constructed an integrated control system for such network distributed hardwares, named T-LECS (Tohoku University - Layered Electronic Control System). T-LECS has also network distributed software design, applying TCP/IP socket communication to interprocess communication. In order to help the communication between the device interfaces and the user interfaces, we defined three layers in T-LECS; an external layer for user interface applications, an internal layer for device interface applications, and a communication layer, which connects two layers above. In the communication layer, we store the data of the system to an SQL database server; they are status data, FITS header data, and also meta data such as device configuration data and FITS configuration data. We present our software system design and the database schema to manage observations of MOIRCS with Subaru.
We report on the results of the performance tests of the HAWAII-2 FPAs for Multi-Object Infra-Red Camera and Spectrograph (MOIRCS). MOIRCS provides wide-field imaging mode (4'x7' F.O.V.) and multi-object spectroscopy mode for the wavelength range from 0.85 to 2.5 μm. To achieve the wide field-of-view with the high angular resolution, we use two 2048 x 2048 HgCdTe FPAs, HAWAII-2. We have made performance tests of both the engineering-grade and the science-grade HAWAII-2 arrays. Array performances such as stability of bias frames, read noise and dark current are evaluated at the operating temperature of 78K. In addition, we search for the optimum well depth, readout speed by changing bias voltages. We have finished tests of the engineering-grade array and the performance of our science-grade arrays is under investigation.
TUFPAC (Tohoku University Focal Plane Array Controller) is an array control system originally designed for flexible control and efficient data acquisition of 2048 x 2048 HgCdTe (HAWAII-2) array. A personal computer operated by Linux OS controls mosaic HAWAII-2s with commercially available DSP boards installed on the PCI bus. Triggered by PC, DSP sends clock data to front-end electronics, which is isolated from the DSP board by photo-couplers. Front-end electronics supply powers, biases and clock signals to HAWAII2. Pixel data are read from four outputs of each HAWAII2 simultaneously by way of four channel preamps and ADCs. Pixel data converted to 16 bit digital data are stored in the frame memory on the DSP board.
Data are processed in the memory when necessary. PC receives the frame data and stores it in the hard disk of PC in FITS format. A set of the DSP board and front-end electronics is responsible for controlling each HAWAII-2. One PC can operate eight mosaic arrays at most. TUFPAC is applicable to the control of CCDs with minor changes of front-end electronics.
We describe an optical design process and image performance evaluations for Multi-Object near-InfraRed Camera and Spectrograph (MOIRCS). MOIRCS is a near-infrared imager and multi-object spectrograph under construction for the Subaru Telescope. MOIRCS provides direct imaging of 4' x 7' F.O.V. with a pixel scale of 0.12". MOIRCS also provides low-resolution multi-object spectroscopy with grisms and cooled multi-slit masks on the Cassegrain focal plane. CaF2, BaF2, ZnSe, and Fused Silica are used as the lens materials. They have high transmission in the near-infrared wavelength. During the design process, we find that a triplet with an achromatic doublet and a ZnSe singlet shows good performance for chromatic aberration. Therefore, we design our optics on the basis of the triplet with ZnSe. The designed optics shows good performances. Ensquared energy within 2 pixel square is more than 85% over the entire wavelength range and F.O.V. We do not need refocusing with the change of observed wavelengths because chromatic aberration is as small as 100 μm by the triplet with ZnSe over the entire wavelength range from 0.85 to 2.5 μm. Lateral chromatic aberration of 15 μm is less than 1 pixel size. Detailed tolerance analysis is done with possible manufacturing and aligning errors considered. The result shows that designed performances will be kept with a probability of 80% with reasonable tolerances. Ghost analysis is also done over entire F.O.V. and we find a ghost image of 13 magnitude fainter than original image that is not significant for our purpose. Therefore, we conclude that we can obtain enough performances with designed optics.
The Subaru Telescope has seven first generation optical and infrared instruments now being handed-over from the instrument teams to the observatory and being offered for its open use. We describe brief history of the telescope project and overview of the instrumentation program. Brief status of the Individual instruments is given separately. Exchanging focal plane and instruments is important for such multi-purpose telescope and the effectiveness of the system with the Subaru Telescope is discussed. Finally, current challenges of the program and future plans are summarized.
MOIRCS (Multi-Object InfraRed Camera and Spectrograph) is one of the second generation instruments for the Subaru Telescope. This instrument is under construction by the National Astronomical Observatory of Japan and Tohoku University. It has imaging and multi-object spectroscopy (MOS) capabilities in the wavelength range from 0.85 μm to 2.5 μm with 4' x 7' F.O.V. The focal plane is imaged onto two 2048 x 2048 pixel HAWAII-2 HgCdTe arrays with a pixel scale of 0."12 pixel-1 through two independent optical trains. The optical design is optimized to maximize K band performance. Unique design of MOIRCS allows multi-object spectroscopy out to K band with cooled multi-slit masks. Twenty-four masks are stored in a mask dewar and are exchanged in the cryogenic environment. The mask dewar has its own vacuum pump and cryogenic cooler, and the masks can be assessed without breaking the vacuum of the main dewar. The two-channel optics and arrays are mounted back-to-back of a single optical bench plate. A PC-Linux based infrared array control system has been prepared to operate HAWAII-2. The first light of MOIRCS is planned in the spring of 2003.
We use the HAWAII-2 (2048 × 2048 HgCdTe) FPAs in MOIRCS (Multi-Object Infra-Red Camera and Spectrograph) for the astronomical use on the Subaru telescope. MOIRCS, which is currently being constructed by Tohoku University and the National Astronomical Observatory of Japan, is one of the second generation instruments for Subaru. It will provide the wide-field imaging mode (4 × 7 arcmin2) and the multi-object spectroscopy mode with the wavelength range of 0.8 to 2.5 μm.
To achieve the large field of view with the high spatial resolution, we use two large-format near-infrared arrays, HAWAII-2. We have developed an infrared array control system specially designed for flexible control and efficient data acquisition of the HAWAII-2 arrays. The array control system, TUFPAC, consists of a personal computer operated by LINUX OS and commercially available DSP boards. By using TUFPAC and the cryostat for array tests, we have made tests of the HAWAII-2 array. In this paper, we report on our array control system and the results of various performance tests for the HAWAII-2 array.
We report on the status of the Cassegrain Instrument Automatic Exchanger (CIAX) control system for the Subaru Telescope. Devices controlled by a shell program in the previous version are now controlled by a macro. It can now be operated safely from remote site. Features of the new system are: 1. New macro. The new macro has two features: (1) Action skip. The macro can skip actions that have been executed earlier. It judges whether to skip by checking the status of devices. Resumption of interrupted macro or reversal from halfway of a process is possible. (2) Macro flexibility: The script has every possible sequential action and chooses actions by checking device status. For instance, it can determine whether the cart is at the telescope or at one of the instrument standby flanges and select a proper hookup command. 2. GUI for macro operation and CGI for rewriting setup files. The new GUI uses a commercial instrument control language. A CGI application accesses setup files. 3. Omni-directional Infrared (IR) LAN. Omni-directional IR LAN is being tested for the cart because radio frequency wireless LAN is prohibited on Mauna Kea to avoid interference to radio telescopes. Conventional IR LAN failed because of its directionality. The CIAX system is now routinely used for instrument exchange. For complete automatic operation, there are still a few tasks left, such as macro-controlled instrument shutdown and restarting, standardizing interfaces and procedure for all instruments and further increasing reliability which is higher already compared to conventional manual exchange.
MIRTOS, Mid-IR Test Observation System, is a high spatial resolution mid IR (MIR) camera for the Subaru Telescope. It consists of two IR imagers. One is for MIR bands with a Si:As array with 320 by 240 pixels. It has 21 by 16 arcsec field of view (FOV) with a pixel scale of 0.067 arcsec. It also images the pupil of the telescope. The other is a near IR camera. A 256 by 256 InSb array with 0.028 arcsec/pixel is used to image 7 by 7 arcsec FOV at one corner of the MIR FOV. We apply Shift-and-Add (SAA) technique; a technique that shifts images detecting the displacements and adds them to cancel seeing. However it is often difficult to shift and add MIR images using a reference within because of low sensitivity in MIR for short exposure time. We solve this problem utilizing NIR images taken simultaneously as position references. We call this method two-wavelength shift-and-add (TWSAA). In this paper we show result from the test observations. 1) Pupil image was taken. It shows hot structures around the secondary mirror that are now planned to be covered by reflecting plates to direct the beam to the sky. 2) Correlation of motion between MIR peak position and NIR centroid position shows that NIR images can be used as TWSAA reference for MIR observations. 3) On a standard star and the core NGC 1068, SAA method was applied to reconstruct images. Resulting images show higher spatial resolution than previous observations.
The Cassegrain Instrument Automatic eXchanger (CIAX) system for the 8.2 meter Subaru Telescope moves instruments between the Cassegrain mounting flange and stand-by flanges without manual intervention. Observation efficiency improves not only because of quick exchanges, scheduled or emergency, but also because of increased flexibility in selecting an optimum instrument for weather conditions or observation goals. Reliable and safer instrument exchanges are achieved by the precision mechanical positioning system (less than 0.5 mm) and an automatic connector system for electrical cables, optical fibers and fluid lines. Instrument down time due to connector/cable failure by human error is eliminated. Interfaces to the telescope flange are standardized for all five Cassegrain instruments (approximately 2000 kgf each) currently in use or under preparation.
The CIAX system especially CIAX-3 increased observation efficiency for Cassegrain test instruments at the early phase of Subaru telescope test observation. In order to control this system effectively and automatically, a control software for the entire system of the CIAX was developed. The software design goals are (1) redundancy for robust system, (2) the safety of the instrument by interlocking, (3) maximum efficiency by automatic control and (4) easy user interface for operator. In this paper, we describe the software which has been being tested through the telescope and instrument commissioning phase.
One of the major problems to retain the efficiency of a telescope is to achieve and maintain high reflectivity in the wide wavelengths of the coatings of the telescope optics. For coating the large mirrors of Subaru Telescope, we employed the conventional evaporation scheme, in the expectation of uniform coverage of the film. In this paper, we will report the installation and the performance verification of the coating facility. This facility consists of a washing tower for stripping off the old coating, an evaporation coating chamber, two trolleys and a scissors- like lifter for handling the primary mirror. To supply a large number of filaments loaded with uniform quality molten metal, the practical solution is to pre-wet the filaments with the agent metal and keep them in a controlled manner before the evaporation. The aluminum film deposit on the test samples in the 8.3 m coating chamber proved the film thickness uniformity matching with the specification. Reflectivity of the fresh surface was over 90% at visible wavelength. In September 1997, we re-aluminized 1.6 m and 1.3 m mirrors for the first time (at least for ourselves) application to the real astronomical telescopes. The resultant surface reflectivity confirmed the feasibility of using pre-wetted filaments.
We are constructing Mid-IR Test Observation System (MIRTOS) as an IR imaging system to evaluate and monitor the performance of the Japanese National Large Telescope, SUBARU. The system combines two cameras. One of the camera is for near-IR (NIR) and the other for mid-IR (MIR). They capture images simultaneously at the rate fast enough to freeze the seeing. Simultaneous NIR images are useful not only for evaluation of the image quality of the telescope but for two-wavelength shift-and-add that preserves diffraction-limited angular resolution of MIR images for a long integration. The system also has telescope emissivity mapping mode that images the telescope entrance pupil in MIR. For the MIR camera, a Santa Barbara Research Center (SBRC) Si:As IBS array with 320 by 240 pixels is used with pixel scale of 0.067 arcsec/pixel that takes enough samples to make diffraction limited images at 8 microns. For the NIR camera, an SBRC InSb array with 256 by 256 is used. Pixel scale is 0.028 arcsec/pixel. It is optimized to detect position of the brightest speckle in images at the wavelength of 2.2 microns with wide enough field of view to image a reference point source. In the emissivity mapping mode, a temperature controlled black body is inserted just outside the dewar window as an absolute calibration source for the telescope emissivity. In this paper we will present detailed design of MIRTOS.
With the advent of ground-based 8-meter telescopes and large format detector arrays, the mid-IR (MIR) astronomy is expected to produce images with higher angular resolution and improved sensitivity than currently available. TO obtain diffraction limited images, it is necessary to compensate for atmospheric seeing. We proposed a scheme in which, by detecting the near-IR (NIR) speckle positions of a reference star, for which we have higher sensitivity than in the MIR, we superpose the MIR images taken simultaneously by shifting its position to cancel the effects of seeing. We call this two-wavelength shift-and-add (TWSAA) method. In this paper, we describe an observation carried out in the fall of 1995 to test the concept. A NIR camera was built with 256 by 256 InSb array detector. With a dichroic splitter, a pair of images of a single start at two wavelengths were formed on two halves of the array. We obtained 126 pairs of images each integrated for 0.1 seconds simultaneously at the K- and L-bands. With the TWSAA method using the K-band images as the reference, the peak signal to noise ratio of the L-band integrated image was enhanced by a factor of 5.7 compared to simple addition.
The infrared instrumentation plan for the Subaru telescope is described. Four approved infrared instruments and one test observation system are now in the construction phase. They are coronagraph imager using adaptive optics (CIAO), cooled mid- infrared camera and spectrograph (COMICS), infrared camera and spectrograph (IRCS), OH-airglow suppressor spectrograph (OHS) and mid-infrared test observation system (MIRTOS). Their performance goals and construction schedules are summarized. The plan for procurement and evaluation of infrared arrays required by these instruments is briefly described.
The overall updated plan for constructing 7 scientific instruments and 3 baseline programs for the 8 m Subaru telescope is shown. Somewhat detailed descriptions are given further for projects to develop large format CCDs, faint object camera and spectrograph (FOCAS), high dispersion spectrograph (HDS), Subaru prime focus camera (Suprime-Cam), and Cassegrain adaptive optics system (AO).