Showing papers in "Astronomical Telescopes and Instrumentation in 2003"

The DEIMOS spectrograph for the Keck II Telescope: integration and testing

Abstract: The DEIMOS spectrograph is a multi-object spectrograph being built for Keck II. DEIMOS was delivered in February 2002, became operational in May, and is now about three-quarters of the way through its commissioning period. This paper describes the major problems encountered in completing the spectrograph, with particular emphasis on optical quality and image motion. The strategies developed to deal with these problems are described. Overall, commissioning is going well, and it appears that DEIMOS will meet all of its major performance goals.

Advanced CCD imaging spectrometer (ACIS) instrument on the Chandra X-ray Observatory

Abstract: The ACIS instrument has been operating for three years in orbit, producing high quality scientific data on a wide variety of X-ray emitting astronomical objects. Except for a brief period at the very beginning of the mission when the CCDs were exposed to the radiation environment of the Outer van Allen Belts which resulted in substantial radiation damage to the front illuminated CCDs, the instrument has operated nearly flawlessly. The following report presents a description of the instrument, the current status of the instrument calibration and a few highlights of the scientific results obtained from the Guaranteed Observer Time.

MIKE: a double-echelle spectrograph for the Magellan Telescopes at Las Campanas Observatory

Abstract: The Magellan Inamori Kyocera Echelle (MIKE) is a double echelle spectrograph designed for use at the Magellan Telescopes at Las Campanas Observatory in Chile. It is currently in the final stages of construction and is scheduled for commissioning in the last quarter of 2002. In standard observing mode, the blue (320-480 nm) and red (440-1000 nm) channels are used simultaneously to obtain spectra over the full wavelength range with only a few gaps in wavelength coverage at the reddest orders. Both channels contain a three-group set of all-spherical, standard optical glass and calcium fluoride lenses which function as both camera and collimator in a double pass configuration. A single, standard echelle grating is used on each side and is illuminated close to true Littrow. Prism cross-dispersers are also used double-pass, and provide a minimum separation between orders of 6 arcsec. Spectral resolution is 19,000 and 25,000 on the red and blue sides, respectively, with a 1 arcsec slit. Typical rms image diameter is less than 0.2 arcsec, so that resolution increases linearly with decreasing slit width. The standard observing mode will use a slit up to 5" long, however a fiber-fed mode will also be available using blocking filters to select the desired orders for up to 256 objects at a time. In this paper, we describe the optical and mechanical design of the instrument.

Science objectives and early results of the DEEP2 Redshift Survey

Abstract: The DEIMOS spectrograph has now been installed on the Keck-II telescope and commissioning is nearly complete. The DEEP2 Redshift Survey, which will take approximately 120 nights at the Keck Observatory over a three year period and has been designed to utilize the power of DEIMOS, began in the summer of 2002. The multiplexing power and high efficiency of DEIMOS enables us to target 1000 faint galaxies per clear night. Our goal is to gather high-quality spectra of ≈ 60,000 galaxies with z>0.75 in order to study the properties and large scale clustering of galaxies at z ≈ 1. The survey will be executed at high spectral resolution, R=λ/Δλ ≈ 5000, allowing us to work between the bright OH sky emission lines and to infer linewidths for many of the target galaxies (for several thousand objects, we will obtain rotation curves as well). The linewidth data will facilitate the execution of the classical redshift-volume cosmological test, which can provide a precision measurement of the equation of state of the Universe. This talk reviews the project, summarizes our science goals and presents some early DEIMOS data.

SINFONI: integral field spectroscopy at 50-milli-arcsecond resolution with the ESO VLT

Abstract: SINFONI is an adaptive optics assisted near-infrared integral field spectrometer for the ESO VLT. The Adaptive OPtics Module (built by the ESO Adaptive Optics Group) is a 60-elements curvature-sensor based system, designed for operations with natural or sodium laser guide stars. The near-infrared integral field spectrometer SPIFFI (built by the Infrared Group of MPE) provides simultaneous spectroscopy of 32 x 32 spatial pixels, and a spectral resolving power of up to 3300. The adaptive optics module is in the phase of integration; the spectrometer is presented tested in the laboratory. We provide an overview of the project, with particular emphasis on the problems encountered in designing and building an adaptive optics assisted spectrometer.

The 1-meter Swedish solar telescope

Abstract: We describe the 1-meter Swedish solar telescope which replaces the former 50-cm solar telescope (SVST) in La Palma. The un-obscured optics consists of a singlet lens used as vacuum window and two secondary optical systems. The first of these enables narrow-band imaging and polarimetry with a minimum of optical surfaces. The second optical system uses a field mirror to re-image the pupil on a 25 cm corrector which provides a perfectly achromatic image, corrected also for atmospheric dispersion. The adaptive optics system is integrated with the design of the telescope but is sufficiently flexible to allow future upgrades. It consists of a low-order bimorph modal mirror with 37 electrodes, allowing near-diffraction-limited imaging a reasonable fraction of the observing time on La Palma. The new telescope became operational at the end of May 2002 and has already proven to be the most highly resolving solar telescope ever built. In this paper, we describe its mechanical and optical design, the polishing and testing of the optics and the instrumentation in use or planned for this telescope.

NAOS, the first AO system of the VLT: on-sky performance

Abstract: NAOS is the first adaptive optics system installed at the VLT 8m telescopes. It was designed, manufactured and tested by a french Consortium under an ESO contract, to provide compensated images to the high angular resolution IR spectro-imaging camera (CONICA) in the 1 to 5 μ m spectral range. It is equipped with a 185 actuator deformable mirror, a tip/tilt mirror and two wavefront sensors, one in the visible and one in the near IR spectral range. It has been installed in November at the Nasmyth focus B of the VLT UT4. During the first light run in December 2001, NAOS has delivered a Strehl ratio of 50 under average seeing conditions for bright guide stars. The diffraction limit of the telescope has been achieved at 2.2 μ m . The closed loop operation has been very robust under bad seeing conditions. It was also possible to obtain a substantial correction with m V=17.6 and m K=13.1 reference stars. The on-sky acceptance tests of NAOS-CONICA were completed in May 2002 and the instrument will be made available to the European astronomical community in October by ESO. This paper describes the system and present the on-sky performance in terms of Strehl ratio, seeing conditions and guide star magnitude.

NAOS-CONICA first on sky results in a variety of observing modes

Abstract: The Adaptive Optics NIR Instrument NAOS-CONICA has been commissioned at the VLT (UT4) between November 2001 and March 2002. After summarizing the observational capabilities of this multimode instrument in combination with the powerful AO-system, we will present first on sky results of the instrumental performance for several non-direct imaging modes: High spatial resolution slit-spectroscopy in the optical and thermal NIR region has been tested. For compact sources below 2 arcsec extension, Wollaston prism polarimetry is used. For larger objects the linear polarization pattern can be analyzed by wire grids down to the diffraction limit. Coronographic masks are applied to optimize imaging and polarimetric capabilities. The cryogenic Fabry-Perot Interferometer in combination with an 8m-telescope AO-system is shown to be a powerful tool for imaging spectroscopy (3D-scans).

Megacam: the new Canada-France-Hawaii Telescope wide-field imaging camera

Abstract: MegaCam is an imaging camera with a 1 square degree field of view for the new prime focus of the 36 meter Canada-France-Hawaii Telescope This instrument will mainly be used for large deep surveys ranging from a few to several thousands of square degrees in sky coverage and from 24 to 285 in magnitude The camera is built around a CCD mosaic approximately 30 cm square, made of 40 large thinned CCD devices for a total of 20 K x 18 K pixels It uses a custom CCD controller, a closed cycle cryocooler based on a pulse tube, a 1 m diameter half-disk as a shutter, a juke-box for the selection of the filters, and programmable logic controllers and fieldbus network to control the different subsystems The instrument was delivered to the observatory on June 10, 2002 and first light is scheduled in early October 2002

Commissioning and performances of the VLT-VIMOS

Abstract: The Visible Multi-Object Spectrograph VIMOS is a wide field survey instrument in the process of being commissioned for operations at the ESO-VLT. During the first commissioning period, the instrument has confirmed its excellent performances in its three basic modes of operation: direct imaging, multi-slit spectroscopy, and integral field spectroscopy. VIMOS provides the largest imaging field at the VLT with 224 arcmin2. It offers an unprecedented multiplex gain in multi-slit spectroscopy, with on order 800 slits which can be observed simultaneously. The integral field unit has a field up to 54x54 arcsec2, with 6400 spectra recorded at once. The overall efficiency of VIMOS combined to the Melipal unit #3 is confirmed to be as computed on the basis of the measured transmission of optical elements. Image quality is confirmed to be excellent, providing images limited by natural seeing in most conditions. High quality slit masks cut by the laser machine coupled to excellent geometric mask to CCD mapping lead to multi-slit spectra of excellent quality. VIMOS is expected to be offered to the ESO community for reguglar observations in early 2003.

SIRUS: a near infrared simultaneous three-band camera

Abstract: We developed a near infrared simultaneous three-band (J, H and Ks) camera, SIRIUS. The design of SIRIUS is optimized to deep, large area surveys in the three IR bands. SIRIUS is equipped with three 1024 x 1024 HgCdTe (HAWAII) arrays, providing simultaneous three-band images. SIRIUS has obtained its first light on the UH 2.2 m telescope in August 2000. SIRIUS is now mounted on the IRSF 1.4 m telescope in Sutherland and is dedicated to deep survey in the southern sky from November 2000. On this telescope, SIRIUS provides 7'.8 x 7'.8 field of view with a pixel scale of 0".45 in all bands. The typical limiting magnitudes are J = 19.2 mag, H = 18.6 mag, Ks = 17.3 mag (15 min. integration, S/N = 10 σ). The effective exposure time (30 sec exposure for each frame) in an hour is about 37 minutes (60%) for each band. Both the instrument and the 1.4 m telescope are in operation.

Prime Focus Imaging Spectrograph for the Southern African Large Telescope: optical design

Abstract: The University of Wisconsin - Madison, together with Rutgers University and the South African Astronomical Observatory, is designing and building an imaging spectrograph for the Prime Focus Instrument Package of the Southern African Large Telescope (SALT). The Prime Focus Imaging Spectrograph (PFIS) will be a versatile instrument specializing in very high throughput, low and medium resolution (R=500-12,500) imaging spectroscopy, using volume phase holographic (VPH) gratings and a double etalon Fabry-Perot interferometer, and spectropolarimetry from 320 to 900 nm. The optical design includes all transmissive optics for high efficiency and compactness. To maintain throughput in the ultraviolet, only fused silica, CaF2 and NaCl are used. As NaCl is very hygroscopic, the design uses NaCl as the inner element in sealed triplets only. For the highest possible first-order spectral resolution, the collimated beam size is 150 mm - the maximum for practical Fabry-Perot etalons. The F/2.2 camera can be articulated to tune the efficiency of the VPH gratings; a complement of six gratings (5 VPH and 1 standard transmission grating) has been designed to fill the resolution-wavelength space available to the instrument. Linear, circular, and all-stokes spectropolarimetry will be performed through the use of Pancharatnam superachromatic waveplates and a Wollaston beamsplitter.

Gemini near-infrared integral field spectrograph (NIFS)

Abstract: NIFS is a near-infrared integral field spectrograph designed for near diffraction-limited imaging spectroscopy with the ALTAIR facility adaptive optics system on Gemini North. NIFS is currently under construction at the Research School of Astronomy and Astrophysics of the Australian National University. Commissioning is planned for 2003. NIFS uses a reflective concentric integral field unit to reformat its 3.0"x3.0" field-of-view into 29 slitlets each 0.1" wide with 0.04" sampling along each slitlet. The NIFS spectrograph has a resolving power of ~ 5300, which is large enough to significantly separate terrestrial airglow emission lines and resolve velocity structure in galaxies. The output format is matched to a 2048x2048 pixel Rockwell HAWAII-2 detector. The detector is read out through a SDSU-2 detector controller connected via a VME interface to the Gemini Data Handling System. NIFS is a fast-tracked instrument that reuses many of the designs of the Gemini Near-InfraRed Imager (NIRI); the cryostat, On-Instrument Wave Front Sensor, control system, and control software are largely duplicates.

A Wide-Field Infrared Camera for the Palomar 200-inch Telescope

Abstract: The availability of both large aperture telescopes and large format near-infrared (NIR) detectors are making wide-field NIR imaging a reality. We describe the Wide-field Infrared Camera (WIRC), a newly commissioned instrument that provides the Palomar 200-inch telescope with such an imaging capability. WIRC features a field-of-view (FOV) of 4.33 arcminutes on a side with its currently installed 1024-square Rockwell Hawaii-I NIR detector. A 2048-square Rockwell Hawaii-II NIR detector will be installed and commissioned later this year, in collaboration with Caltech, to give WIRC an 8.7 arcminute FOV on a side. WIRC mounts at the telescope's f/3.3 prime focus. The instrument's seeing-limited optical design, optimized for the JHK atmospheric bands, includes a 4-element refractive collimator, two 7-position filter wheels that straddle a Lyot stop, and a 5-element refractive f/3 camera. Typical seeing-limited point spread functions are slightly oversampled with a 0.25 arcsec per pixel plate scale at the detector. The entire optical train is contained within a cryogenic dewar with a 2.5 day hold-time. Entrance hatches at the top of the dewar allow access to the detector without disruption of the optics and optical alignment. The optical, mechanical, cryogenic, and electronic design of the instrument are described, a commissioning science image and performance analyses are presented.

Prime Focus Imaging Spectrograph for the Southern African Large Telescope: operational modes

Abstract: The Prime Focus Imaging Spectrograph (PFIS) will be the workhorse first-light instrument on the Southern African Large Telescope (SALT). Scheduled for commissioning in late 2004, PFIS is a versatile high-throughput imaging spectrograph with a complement of 5 volume-phase holographic gratings for spectroscopic programs from 3200a to 9000a at resolutions of R=1500 to R=6000. A magazine of 6 longslits and 30 custom laser-milled slitmasks enables single- or multi-object spectroscopy over an 8 arcminute diameter field. With the gratings stowed, a dual-etalon Fabry-Perot subsystem enables imaging spectroscopy at R=500, R=3000, and R=12,500. The polarization subsystem, consisting of a polarizing beam-splitter used in conjunction with half- and quarter-wave plates, allow linear or circular polarimetric measurements in ANY of the spectroscopic modes. Three mosaiced rapid-readout frame-transfer CCDs provide the capability for time-resolved sampling at rates in excess of 10 Hz. Combinations of these subsystems permit novel observing modes for specialized scientific programs. Examples include high-time resolution multi-object spectral polarizmetry of accreting compact objects, and Fabry-Perot polarimetry or imaging spectral polarimetry of nebulae and stellar clusters. The demands of queue-scheduled observing on a fixed-altitude telescope require that the instrument be capable of rapid reconfiguration between modes.

Adaptive optics system for the new Swedish solar telescope

Abstract: The 1-meter Swedish solar telescope is a new solar telescope that was put in operation on the island of La Palma in the Canary Islands at the end of May 2002. The goal of this telescope is to reach its diffraction limited resolution of 0.1 arcsec in blue light. This has already been achieved by use of a low-order adaptive optics (AO)system. This paper describes the AO system initially developed for the former 50-cm Swedish Vacuum Solar Telescope (SVST) and further improved for the new telescope. Both systems use a combination of bimorph modal mirrors and Shack-Hartmann wavefront sensors. Unique to these systems are that they rely on a single workstation or a PC to do all the computations required to extract and pre-process the images, measure their positions using cross correlation techniques and for controlling the deformable mirror. This is in the present system possible by using the PERR instruction available on Compaq's Alpha architecture and in the new system using the PSADDBW instruction, available on Pentium 4 and Athlon processors. We describe both these systems with an emphasis on the performance, the ease of support and upgrades of performance. We also describe the optimization of the electrode geometry for the new 37-electrode bimorph mirror, supplied by AOPTIX Technologies, Inc., for controlling Karhunen--Loeve modes. Expected performance, based on closed-loop simulations, is discussed.

SHARC II: a Caltech Submillimeter Observatory facility camera with 384 pixels

Abstract: SHARC II is a background-limited 350 micron and 450 micron facility camera for the Caltech Submillimeter Observatory undergoing commissioning in 2002. The key component of SHARC II is a 12 x 32 array of doped silicon 'pop-up' bolometers developed at NASA/Goddard. Each 1 mm x 1 mm pixel is coated with a 400 Omega/square bismuth film and located lambda/4 above a reflective backshort to achieve greater than 75% absorption efficiency. The pixels cover the focal plane with greater than 90% filling factor. At 350 microns, the SHARC II pixels are separated by 0.65 lambda/D. In contrast to the silicon bolometers in the predecessor of SHARC II, each doped thermistor occupies nearly the full area of the pixel, which lowers the 1/f knee of tile detector noise to less than 0.03 Hz, under load, at tile bath temperature of 0.36 K. The bolometers are AC-biased and read in 'total power' mode to take advantage of the improved stability. Each bolometer is biased through a custom approx. 130 MOmega CrSi load resistor at 7 K and read with a commercial JFET at 120 K. The JFETs and load resistors are integrated with the detectors into a single assembly to minimize microphonic noise. Electrical connection across the 0.36 K to 4 K and 4 K to 120 K temperature interfaces is accomplished with lithographed metal wires on dielectric substrates. In the best 25% of winter nights on Mauna Kea, SHARC II is expected to have an NEFD at 350 micron of 1 Jy Hz(sup -1/2) or better. The new camera should be at least 4 times faster at detecting known point sources and 30 times faster at mapping large areas compared to the prior instrument.

Overview of the Advanced Camera for Surveys on-orbit performance

Abstract: We present an overview of the ACS on-orbit performance based on the calibration observations taken during the first three months of ACS operations. The ACS meets or exceeds all of its important performance specifications. The WFC and HRC FWHM and 50% encircled energy diameters at 555 nm are 0.088" and 0.14", and 0.050" and 0.10". The average rms WFC and HRC read noises are 5.0 e- and 4.7 e-. The WFC and HRC average dark currents are ~ 7.5 and ~ 9.1 e-/pixel/hour at their operating temperatures of - 76°C and - 80°C. The SBC + HST throughput is 0.0476 and 0.0292 through the F125LP and F150LP filters. The lower than expected SBC operating temperature of 15 to 27°C gives a dark current of 0.038 e-/pix/hour. The SBC just misses its image specification with an observed 50% encircled energy diameter of 0.24" at 121.6 nm. The ACS HRC coronagraph provides a 6 to 16 direct reduction of a stellar PSF, and a ~1000 to ~9000 PSF-subtracted reduction, depending on the size of the coronagraphic spot and the wavelength. The ACS grism has a position dependent dispersion with an average value of 3.95 nm/pixel. The average resolution λ/Δλ for stellar sources is 65, 87, and 78 at wavelengths of 594 nm, 802 nm, and 978 nm.

Doppler broadening as a lower limit to the angular resolution of next-generation Compton telescopes

Abstract: The angular resolution of a telescope which detects gamma-rays via the Compton effect is fundamentally limited below a few hundred keV by the fact that the target electrons have an indeterminable momentum inside their atoms which introduces an uncertainty in the recoil energy of the Compton electron and the scattered photon. This additional component in the energy and momentum equation results in a Doppler broadening of the angular resolution compared to the standard Compton equation for a target at rest. The deterioration in resolution is most pronounced for low photon energy, high scatter angle, and high Z of the scatter material. This physical limit to the angular resolution of a Compton telescope is present even if all other parameters (e.g. energy and position) are measured with high accuracy. For different Compton scatter materials such as silicon, germanium and xenon, which are used in current telescope designs, the best possible angular resolution as a function of photon energy and scatter angle is calculated. Averaged over all scatter angles and energies, the Doppler-limited angular resolution of silicon is a factor of ~1.6 better than that of germanium and a factor of ~1.9 better than that of xenon. Looking at the Doppler limit of materials from Z=1 to 90 the best angular resolution can be reached for alkaline and alkaline earth metals, the worst for elements with filled p-orbitals (noble gases) and d-orbitals (e.g. Pd and Au). Of all semiconductors which might be used in a next generation Compton telescope, silicon seems to be the best choice.

SOLIS: an innovative suite of synoptic instruments

Abstract: SOLIS (Synoptic Optical Long-term Investigations of the Sun) is a suite of three innovative instruments under construction that will greatly improve ground-based synoptic solar observations. The Vector Spectromagnetograph (VSM) is a compact, high-throughput vector-polarimeter with an active secondary mirror, an actively controlled grating spectrograph, and two high-speed cameras with silicon-on-CMOS-multiplexer hybrid focal plane arrays. It will measure the magnetic field strength and direction over the full solar disk within 15 minutes. The Full-Disk Patrol (FDP) takes full-disk solar intensity and Doppler images in various spectral lines and in the continuum at a high cadence through liquid-crystal tuned birefringent filters. The Integrated Sunlight Spectrometer (ISS) uses a fiber-fed spectrograph to measure minute changes of the Sun-as-a-star in many spectral lines. A high degree of automation and remote control provides fast user access to data and flexible interaction with the data-collection process. SOLIS is currently in the final assembly phase and will become operational early in 2003.

Second generation instruments for the Laser Interferometer Gravitational Wave Observatory (LIGO)

Abstract: The interferometers being planned for second generation LIGO promise an order of magnitude increase in broadband strain sensitivity-with the corresponding cubic increase in detection volume-and an extension of the observation band to lower frequencies. In addition, one of the interferometers may be designed for narrowband performance, giving further improved sensitivity over roughly an octave band above a few hundred Hertz. This article discusses the physics and technology of these new interferometer designs, and presents their projected sensitivity spectra.

MASS: a monitor of the vertical turbulence distribution

Abstract: The MASS (Multi-Aperture Scintillation Sensor) instrument consists of a 14-cm off-axis reflecting telescope and a detector unit which measures the scintillations of single stars in four concentric zones of the telescope pupil using photo-multipliers. Statistical analysis of these signals yields information of the vertical turbulence profile with a resolution of dh/h=0.5. We describe the instrument and present the results of its first field tests, including comparisons with DIMM seeing monitor and generalized SCIDAR. MASS will be used to obtain the extensive statistics of turbulence profiles at potential sites of future giant telescopes, as needed to predict the quality of adaptive seeing compensation.

ARCES: an echelle spectrograph for the Astrophysical Research Consortium (ARC) 3.5m telescope

Abstract: A new echelle spectrograph was commissioned in 1999 for the ARC 3.5 meter telescope. The key features of the instrument are that it has a resolution of 9 km/sec, limited by the pixel size of the CCD; has no moving parts behind the slit during observation; provides complete spectral coverage from 3200A to 10000A, limited by the prism cross disperser material on the blue side and by the CCD sensitivity on the red side; provides blazeless spectra; achieves S/N>3000; and is remotely operable. The instrument is being used for studies of abundances in stars and for a large survey of diffuse interstellar bands.

The Phoenix Spectrograph at Gemini South

Abstract: Phoenix, a high resolution near-infrared spectrograph build by NOAO, was first used on the Gemini South telescope in December 2001. Previously on the Kitt Peak 2.1 and 4 meter telescopes, Phoenix received a new detector, as well as modified refrigeration, mounting, and handling equipment, prior to being sent to Gemini South. Using a two-pixel slit the resolution is ~75,000, making Phoenix the highest resolution infrared spectrograph available on a 6-10 meter class telescope at the current time. Modifications to and performance of the instrument are discussed. Some results on Magellanic cloud stars, brown dwarf stars, premain-sequence objects, and stellar exotica are reviewed briefly.

The COR1 inner coronagraph for STEREO-SECCHI

Abstract: The Solar Terrestrial Relations Observatory (STEREO) is a pair of identical satellites that will orbit the Sun so as to drift ahead of and behind Earth respectively, to give a stereo view of the Sun. STEREO is currently scheduled for launch in November 2005. One of the instrument packages that will be flown on each of the STEREO spacecrafts is the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI), which consists of an extreme ultraviolet imager, two coronagraphs, and two side-viewing heliospheric imagers to observe solar coronal mass ejections all the way from the Sun to Earth. We report here on the inner coronagraph, labeled COR1. COR1 is a classic Lyot internally occulting refractive coronagraph, adapted for the first time to be used in space. The field of view is from 1.3 to 4 solar radii. A linear polarizer is used to suppress scattered light, and to extract the polarized brightness signal from the solar corona. The optical scattering performance of the coronagraph was first modeled using both the ASAP and APART numerical modeling codes, and then tested at the Vacuum Tunnel Facility at the National Center for Atmospheric Research in Boulder, Colorado. In this report, we will focus on the COR1 optical design, the predicted optical performance, and the observed performance in the lab. We will also discuss the mechanical and thermal design, and the cleanliness requirements needed to achieve the optical performance.

MAD the ESO multi-conjugate adaptive optics demonstrator

Abstract: Multi-Conjugate Adaptive Optics (MCAO) is working on the principle to perform wide field of view atmospheric turbulence correction using many Guide Stars located in and/or surrounding the observed target. The vertical distribution of the atmospheric turbulence is reconstructed by observing several guide stars and the correction is applied by some deformable mirrors optically conjugated at different altitudes above the telescope. The European Southern Observatory together with external research institutions is going to build a Multi-Conjugate Adaptive Optics Demonstrator (MAD) to perform wide field of view adaptive optics correction. The aim of MAD is to demonstrate on the sky the feasibility of the MCAO technique and to evaluate all the critical aspects in building such kind of instrument in the framework of both the 2nd generation VLT instrumentation and the 100-m telescope OWL. In this paper we present the conceptual design of the MAD module that will be installed at one of the VLT unit telescope in Paranal to perform on-sky observations. MAD is based on a two deformable mirrors correction system and on two multi-reference wavefront sensors capable to observe simultaneously some pre-selected configurations of Natural Guide Stars. MAD is expected to correct up to 2 arcmin field of view in K band.

LUCIFER : a multi-mode NIR instrument for the LBT

Abstract: LUCIFER (LBT NIR-Spectroscopic Utility with Camera and Integral-Field Unit for Extragalactic Research) is a NIR spectrograph and imager for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona. It is built by a consortium of five German institutes and will be one of the first light instruments for the LBT. Later, a second copy for the second mirror of the telescope will follow. Both instruments will be mounted at the bent Gregorian foci of the two individual telescope mirrors. The final design of the instrument is presently in progress. LUCIFER will work at cryogenic temperature in the wavelength range from 0.9 μm to 2.5 μm. It is equipped with three exchangeable cameras for imaging and spectroscopy: two of them are optimized for seeing-limited conditions, the third camera for the diffraction-limited case with the LBT adaptive secondary mirror working. The spectral resolution will allow for OH suppression. Up to 33 exchangeable masks will be available for longslit and multi-object spectroscopy (MOS) over the full field of view (FOV). The detector will be a Rockwell HAWAII-2 HgCdTe-array.

The Kepler mission: a wide-field-of-view photometer designed to determine the frequency of Earth-size planets around solar-like stars

Abstract: NASA's Kepler Mission is designed to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. It uses transit photometry from space to determine planet size relative to its star and orbital period. From these measurements, and those of complementary ground-based observations of planet-hosting stars, and from Kepler's third law, the actual size of the planet, its position relative to the habitable zone, and the presence of other planets can be deduced. The Kepler photometer is designed around a 0.95 m aperture wide field-of-view (FOV) Schmidt type telescope with a large array of CCD detectors to continuously monitor 100,000 stars in a single FOV for four years. To detect terrestrial planets, the photometer uses differential relative photometry to obtain a precision of 20 ppm for 12th magnitude stars. The combination of the number of stars that must be monitored to get a statistically significant estimate of the frequency of Earth-size planets, the size of Earth with respect to the Sun, the minimum number of photoelectrons required to recognize the transit signal while maintaining a low false-alarm rate, and the areal density of target stars of differing brightness are all critical to the photometer design.

KAOS: Adaptive optics system for the Vacuum Tower Telescope at Teide Observatory

Abstract: We are completing the integration of a solar adaptive optics system KAOS at the 70 cm diameter Vacuum Tower telescope (VTT) on Tenerife. The system is capable to compensate some 30 modes of wavefront aberration with closed-loop bandwidth of about 100 Hz anywhere on the solar disk. We describe the design goals, the main characteristics of KAOS and present a first demonstration of its performance.

A Novel Double Imaging Camera (ANDICAM)

Abstract: We describe an instrument that is capable of taking simultaneous images at one optical (UBVRI) and one near-infrared (JHK) wavelength. The instrument uses relatively simple optics and a dichroic to image the same field on to an optical CCD and an HgCdTe array. The mechanical and thermal design is similar to previous instruments built by our group and the array controllers are based on the same architecture. The instrument has been in use for the past four years on the CTIO/Yale 1m telescope in Chile and has an excellent operational/reliability record. A number of notable science results have been obtained with the instrument; especially interesting are several photometric monitoring projects that have been possible, since the instrument is available every night on the telescope.