The Sloan Digital Sky Survey represents a new paradigm for optical astronomy. It is a consortium involving several hundred astronomers from the US, Japan, and Germany, and aims to obtain basic photometric and spectroscopic data of a large representative region of the high Galactic latitude sky. Using a dedicated wide-field 2.5m telescope and unique instrumentation and software, it is imaging the sky in five photometric bands, and obtaining high-quality spectra of magnitude-limited samples of galaxies and quasars. Although the original survey goals are oriented towards large-scale structure studies, the survey is yielding major results in fields ranging from high-redshift quasars to Galactic structure, from studies of galaxy properties to asteroids, from brown dwarfs to fluctuations in the Earth’s atmosphere. I will give you a broad overview of some of these results and give thoughts on some of the types of results we can look forward to in the future of the survey.

A large wide-field telescope and camera with optical throughput over 200 m² deg² -- a factor of 50 beyond what we currently have -- would enable the detection of faint moving or bursting optical objects: from Earth threatening asteroids to energetic events at the edge of the optical universe. An optimized design for LSST is a 8.4 m telescope with a 3 degree field of view and an optical throughput of 260 m² deg². With its large throughput and dedicated all-sky monitoring mode, the LSST will reach 24th magnitude in a single 10 second exposure, opening unexplored regions of astronomical parameter space. The heart of the 2.3 Gpixel camera will be an array of imager modules with 10 μm pixels. Once each month LSST will survey up to 14,000 deg² of the sky with many ~10 second exposures. Over time LSST will survey 30,000 deg² deeply in multiple bandpasses, enabling innovative investigations ranging from galactic structure to cosmology. This is a shift in paradigm for optical astronomy: from "survey follow-up" to "survey direct science." The resulting real-time data products and fifteen petabyte time-tagged imaging database and photometric catalog will provide a unique resource. A collaboration of ~80 engineers and scientists are gearing up to confront this exciting challenge.

We explore a possible "killer app" for the LSST and similar surveys: imaging mass in three dimensions. We describe its scientific importance, practical techniques for realizing it, the current state of the art and how it might scale to the LSST.

Some results from the near infrared camera SIRIUS are presented. SIRIUS is designed for deep and wide JHKs-bands simultaneous surveys, being equipped with three science-grade HAWAII (1024×1024) arrays. SIRIUS is attached on a dedicated 1.4m telescope (IRSF) at Sutherland observatory in South Africa. The field of view is 7.8'×7.8', the pixel scale is 0.45", and the limiting magnitude is J=19.2, H=18.6, Ks=17.3 (S/N=10σ and 15minutes integration) with the 1.4m telescope. The survey of southern sky began in November 2000. SIRIUS was also used on the University of Hawaii 2.2m telescope at Mauna Kea for three times in August 2000, October 2000, and September 2001. Surveys of several northern sky areas were done. Unbiased deep survey for 6 degree square area of Large Magellanic Cloud (LMC) is one of the key programs with the 1.4m telescope. Several clusters of intermediate mass YSO candidates have been discovered so far. Monitoring surveys of several selected areas of LMC have also been carried out for detection of variable stars. The other main science programs of SIRIUS are deep imaging surveys of star forming regions in our galaxy, brown dwarf surveys in clusters, search for galaxies behind the Milky way (the Zone of Avoidance), and surveys toward the galactic center.

We give an overview of the current status of the VISTA (Visible and Infrared Survey Telescope for Astronomy) project to build a 4-m wide field survey telescope to be operated by ESO (the European Southern Observatory) at the Cerro Paranal Observatory in Chile. First light in 2006 will be with the Infrared (J, H, Ks) Camera with a 1.65 degrees diameter field of view able to accommodate sixteen 2k × 2k IR detectors with 0.34''pixel size. Some motivations driving the choice of site, current design, and operational mode are discussed. We outline some innovative features of the system, which were necessary to deal with, or arose from, the very large field of view, including a cold baffle (rather than cold stop) in the IR camera, lack of traditional telescope focus, f/1 primary mirror, thermal control of the IR camera etc. These are cross-referenced to more detailed analyses by members of the VISTA Project Office team presented at this meeting. Estimated IR performance for VISTA is given. The scientific gains from adding the 2.1 degrees field of view Visible Camera when funds become available are stressed. The problems of processing 0.4TB of survey data acquired each night are discussed.

This paper is a status report on the VST (VLT Survey Telescope) project, aimed at creating a new-technology wide-field facility at the European Southern Observatory (ESO) at Paranal, Chile. The VST telescope is a 2.6 m alt-az reflector built by INAF - Capodimonte Astronomical Observatory (OAC). The camera is a 16k × 16k CCD mosaic provided by the international OmegaCAM consortium. In spite of a recent disastrous event, which caused the loss of the primary mirror while it was transferred from Europe to Chile by ESO, the goal is still that the facility may start to operate in the first quarter of 2004, as planned.

The Supernova / Acceleration Probe (SNAP) is a proposed space-borne observatory that will survey the sky with a wide-field optical/near-infrared (NIR) imager. The images produced by SNAP will have an unprecedented combination of depth, solid-angle, angular resolution, and temporal sampling. For 16 months each, two 7.5 square-degree fields will be observed every four days to a magnitude depth of AB=27.7 in each of the SNAP filters, spanning 3500-17000Å. Co-adding images over all epochs will give AB=30.3 per filter. In addition, a 300 square-degree field will be surveyed to AB=28 per filter, with no repeated temporal sampling. Although the survey strategy is tailored for supernova and weak gravitational lensing observations, the resulting data will support a broad range of auxiliary science programs.

The Nearby Supernova Factory (Snfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The Snfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000Å for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the Snfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The Snfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. The pipeline to obtain, transfer via wireless and standard internet, and automatically process the search images is in operation. Software and hardware development is now underway to enable the execution of follow-up spectroscopy of supernova candidates at the Hawaii 2.2-m telescope via automated remote control of the telescope and the IFU spectrograph/imager.

The Deep Lens Survey (DLS) is a deep BV Rz' imaging survey of seven 2°×2° degree fields, with all data to be made public. The primary scientific driver is weak gravitational lensing, but the survey is also designed to enable a wide array of other astrophysical investigations. A unique feature of this survey is the search for transient phenomena. We subtract multiple exposures of a field, detect differences, classify, and release transients on the Web within about an hour of observation. Here we summarize the scientific goals of the DLS, field and filter selection, observing techniques and current status, data reduction, data products and release, and transient detections. Finally, we discuss some lessons which might apply to future large surveys such as LSST.

We developed a new 1.0 m telescope with a 3 degree flat focal plane to which a mosaic CCD camera with 10 2k×4k chips is fixed. The system was set up in February 2002, and is now undergoing the final fine adjustments. Since the telescope has a focal length of 3 m, a field of 7.5 square degrees is covered in one image. In good seeing conditions, 1.5 arc seconds, at the site located in Bisei town, Okayama prefecture in Japan, we can expect to detect down to 20th magnitude stars with an exposure time of 60 seconds. Considering a read-out time, 46 seconds, of the CCD camera, one image is taken in every two minutes, and about 2,100 square degrees of field is expected to be covered in one clear night. This system is very effective for survey work, especially for Near-Earth-Asteroid detection.

The design of high performance motion control systems for large telescopes is an area of major interest. To counteract the effects of parameter variations and uncertainties as well as wind buffeting a robust controller must be designed. This paper outlines an approach for designing H-infinity controllers for the main axes of a class of telescopes. Some choices made during the controller design are briefly considered. The impact on system performance arising from structural resonance, wind buffeting, drive train stiffness and drive stiction are discussed. The controllers are developed from state space models that include wind disturbances. Davenport wind power spectrum is used to characterize wind buffeting. Sub-optimal H-infinity controllers are designed using standard tools in Matlab. The controllers are designed to operate in continuous time but for implementation they are discretized with a sampling time interval of 2.5 milliseconds. Experimental results for both azimuth and altitude are presented and discussed. A summary of RMS servo errors for tracking and pointing is also included.

We announce the first public release of the SDSS Moving Object Catalog, with SDSS observations for 58,117 asteroids. The catalog lists astrometric and photometric data for moving objects observed prior to Dec 15, 2001, and also includes orbital elements for 10,592 previously known objects, and confirm that asteroid dynamical families, defined as clusters in orbital parameter space, also strongly segregate in color space. Their distinctive optical colors indicate that the variations in chemical composition within a family are much smaller than the compositional differences between families, and strongly support earlier suggestions that asteroids belonging to a particular family have a common origin.

The Large-aperture Synoptic Survey Telescope, LSST, will have an effective aperture of ~6.5 m and a 3 degree field of view. Its 3-mirror optical system with 8.4 m primary, 3.5 m secondary, 4.2 meter tertiary mirrors and a trapped focus offer unique telescope design challenges. The operation of this telescope will require quick slewing, accurate tracking and alignment maintained actively for 0.25 arcsec images in the presence of wind and gravity perturbations. We describe our current design for which finite element models show a lowest frequency resonance above 7 Hertz. Further refinement promises an even stiffer structure. The design has been optimized for low mass (230 tons), minimal inertia (2.4×10⁶ kg-m² in elevation, 3.2×10⁶ kg-m² in azimuth) for fast response. It takes advantage of several concepts proven in the Large Binocular Telescope mount, which has shown high performance at low cost. These include elevation motion on C rings placed under the primary mirror, a primary mirror cell built as an integral part of the structure, and the elevation axis placed behind and off to the side of the primary vertex, to achieve balance with minimum mass.

This paper presents an improved optical design for the LSST, an f/1.25 three-mirror telescope covering 3.0 degrees full field angle, with 6.9 m effective aperture diameter. The telescope operates at five wavelength bands spanning 386.5 nm to 1040 nm (B, V, R, I and Z). For all bands, 80% of the polychromatic diffracted energy is collected within 0.20 arc-seconds diameter. The reflective telescope uses an 8.4 m f/1.06 concave primary, a 3.4 m convex secondary and a 5.2 m concave tertiary in a Paul geometry. The system length is 9.2 m. A refractive corrector near the detector uses three fused silica lenses, rather than the two lenses of previous designs. Earlier designs required that one element be a vacuum barrier, but now the detector sits in an inert gas at ambient pressure, with the last lens serving as the gas barrier. Small adjustments lead to optimal correction at each band. Each filter has a different axial thickness, and the primary and tertiary mirrors are repositioned for each wavelength band. Features that simplify manufacturing include a flat detector, a far less aspheric convex secondary (10 μm from best fit sphere) and reduced aspheric departures on the lenses and tertiary mirror. Five aspheric surfaces, on all three mirrors and on two lenses, are used. The primary is nearly parabolic. The telescope is fully baffled so that no specularly reflected light from any field angle, inside or outside of the full field angle of 3.0 degrees, can reach the detector.

The number of objects orbiting the Earth has been increasing dramatically since the launch of Sputnik in the late 1950's. Thousands of orbiting objects, active satellites or debris, need to be tracked to ensure the accuracy of their orbital elements. To meet the growing needs for space surveillance and orbital debris tracking, the Air Force Maui Optical and Supercomputing Site (AMOS) on Maui, Hawaii is bringing back one of the original Baker-Nunn cameras as the Phoenix Telescope to contribute to these efforts. The Phoenix Telescope retains the wide-field attribute of the original system, while the addition of enhanced optics allows the use of a 4k × 4k pixels back-illuminated CCD array as the imaging camera to provide a field-of-view of 6.8 degrees square (9.6 degrees diagonal). An integrated software suite automates the majority of the operational functions, and allows the system to process in-frame multiple-object acquisitions. The wide-field capability of the Phoenix Telescope is not only an effective tool in the space surveillance effort, but it also has a very high potential value for efforts in searching for and tracking Near-Earth objects (NEO). The large sky coverage provided by the Phoenix Telescope also has the potential to be used in searching for supernova and other astronomical phenomena. An overview of the Phoenix system and results obtained since first-light are presented.

The Douglas Mawson Telescope (DMT) is a proposed 2 m telescope to be situated on the Antarctic plateau. The proposal comes from Australia, and invites participation by other nations, especially those already active in Antarctic astronomy; such as Italy, France and the United States. The DMT will be equipped with instrumentation to perform wide-field imaging from the near to far infrared. Results from an extensive site testing campaign over the last decade indicates that an Antarctic infrared telescope can be one to two orders of magnitude more sensitive than any other ground based telescope of the same size. The DMT will be an important tool for astrophysical research. It will also be beneficial as a technological test bed for future large (8-10 m class) Antarctic telescopes and interferometers, and for space-based telescopes. This paper analyses the performance of the DMT in terms of the achievable resolution, field-of-view, sensitivity and survey depth and compares it to a similar sized telescope located with the characteristic mid-latitude atmosphere of Mauna Kea.

We present the Advanced Robotic Agile Observatory (ARAGO), a project for a large variability survey of the sky, in the range 10^-8Hz (year) to 1Hz. Among its scientific objectives are the detection of cosmic gamma-ray bursts, both on alert and serendipitously, orphan afterglows, extrasolar planets, AGNs, quasar microlensing, variable and flare stars, trans-neptunian asteroids, Earth-grazers, orbital debris, etc. A large Education and Public Outreach program will be an important part of the project. The telescope itself will be made of Silicon Carbide, allowing, among other advantages, a very light weight and agile capabilities. ARAGO will be fully autonomous, i.e. there will be no human intervention from the request to the data processing and result dissemination, nor to assist night or day operations. ARAGO will start routine observation by mid-2005.

The support and position control systems for both the primary and secondary mirror of the SDSS Telescope allow the mirrors up to 12 mm of precisely positioned axial motion, as well as limited tilt and transverse motion. This paper describes the final design and operation of these systems. Some relative strengths and limitations of the components and problems encountered with their implementation are also summarized.

The IFA and collaborators are embarking on a project to develop a 4-telescope synoptic survey instrument. While somewhat smaller than the 6.5m class telescope envisaged by the decadal review in their proposal for a LSST, this facility will nonetheless be able to accomplish many of the LSST science goals. In this paper we will describe the motivation for a 'distributed aperture' approach for the LSST, the current concept for Pan-STARRS -- a pilot project for the LSST proper -- and its performance goals and science reach. We will also discuss how the facility may be expanded.

The first results obtained from the Site Campaigns performed in the last years in different locations of the Antarctic Continent and the acquired experience obtained from the first astronomical IR measures with SPIREX, have in fact opened the way to a present time challenge, about the installation of a large IR Telescope in the best possible site on earth, that will be competitive with the present frontier of ground based and space telescopes in the Infrared range. A project in this context has been submitted to the Italian Plan for Antarctic Research (PNRA), in collaboration with French and Australian colleagues that began to be funded this year. The project entitled “A preliminary study for a Large Infrared Telescope at Dome C”, will lay the bases for the realization of a non-conventional instrument for the mid-IR domain, suited for the very particular and severe Antarctic situation. In this first paper a general overview is done about the future development plan for the GTA (Grande Telescopio Antartico), paying attention to the following themes: Large aperture and low emissivity and high reliability of Antarctic IR telescopes High resolution and very high sensitivity objectives for a mid-ir Survey Telescope. Non-conventional observing modes for quasi drift-scan measurements.

An important parameter that defines the effectiveness and efficiency of any optical or infrared sky survey is the atmospheric character of the observing site. Of prime importance is the sky spectral brightness, which determines the sensitivities and the observing time required to complete a particular survey. This paper presents observations of the near-infrared sky spectral brightness measured at the South Pole throughout the 2001 winter with an automated instrument, the Near Infrared Sky Monitor (NISM). Results from the NISM confirm that the South Pole sky spectral brightness is up to two orders of magnitude lower than at any other ground-based site, consistent with previous observations. These results indicate that the Antarctic plateau is an ideal place to site a future infrared sky survey telescope.

The Sloan Digital Sky Survey (SDSS) imaging camera saw first light in May 1998, and has been in regular operation since the start of the survey in April 2000. We review here key elements in the design of the instrument driven by the specific goals of the survey, and discuss some of the operational issues involved in keeping the instrument ready to observe at all times and in monitoring its performance. We present data on the mechanical and photometric stability of the camera, using on-sky survey data as collected and processed to date.

OmegaCAM, a 16k×16k-pixel wide field optical camera, and the VLT Survey Telescope (VST) that is to host it, will constitute a major sky surveying machine that becomes operational in 2004 at ESO’s Paranal Observatory. It maps one square degree of sky with 0.21 arcsec sized pixels. Both individual programs, including monitoring programs, and large sky survey programs are planned. Here we present the integrated design of the VST-OmegaCAM survey machine, including the hardware (large filters and shutter, cf(4836-34)), the VLT compliant control software (cf(4848-10)) and the strongly procedurized observing and calibration strategies. The strict data taking procedures facilitate pipeline data reduction procedures both for the calibration and the science data. In turn, the strongly procedurized data handling allows European-wide federations of data-products. The ASTRO-WISE consortium aims to provide a survey system that makes this possible. On-the-fly re-processing of archival data on the request of individual users with their own plug-ins or newly derived calibrations sets are facilitated in an internationally distributed system. Compared to the classical more static wide-field image archives the newly designed system is characterized by a much more dynamical type of archiving.

The 256-Mega-Pixel imager OmegaCAM will become the wide-field camera at the VLT-Survey-Telescope of the ESO Paranal Observatory. The camera will cover 1 square-degree field of view at the 2.6-metre VST telescope with 16k×16k pixel resolution. The opto- and electro-mechanical design is the responsibility of a Dutch-German-Italian consortium whereas the cryogenic detector system is built by ESO. The design phase had been finalized with a successful Final-Design-Review in autumn 2001. Procurement and manufacturing is ongoing till the end of the year 2002 followed by an extensive testing period before Preliminary-Acceptance-in-Europe. The paper will present the camera design including the results of design analyses and performance assessments of which optical and finite-element-analyses will be emphasized. The actual design of large-format optical filters will be addressed as well. Their procurement turned out as a challenging issue.

We describe progress in removing image motion over large fields of view. A camera using a new type of CCD has been commissioned and we report first results which are very promising for wide field imaging. We are embarking on a project to build a new type of astronomical CCD which should provide image motion compensation over arbitrarily large fields of view, very fast readout, autoguiding capability, good red sensitivity, and should be significantly less expensive than the present generation of CCDs.

The WIYN One Degree Imager (ODI) will be a well-sampled (0.11” per pixel) imager that provides a full one degree square field of view (32K×32K pixels). ODI will utilize high resistivity, red sensitive, orthogonal transfer (OT) CCDs to provide rapid correction for image motion arising from telescope shake, guider errors, and atmospheric effects. ODI will correct the full field of view by deploying 64 array packages having a total of 4096 independently controllable OTCCDs that can correct individually for local (2 arcmin) image motion. Each array package is an orthogonal transfer array (OTA) of 64 CCDs arranged in an 8×8 grid. Each CCD has 512×512 pixels. We expect the median image quality at the WIYN 3.5m telescope in RIZ to be 0.52”, 0.43”, and 0.35” FWHM. ODI makes optimal use of the WIYN telescope, which has superb optics, excellent seeing characteristics, a natural 1.4 degree field of view (with a new corrector), and can serve as a pathfinder for LSST in terms of detectors, data pipelines, operations strategies, and scientific motivation.

The LSST Instrument is a wide-field optical (0.3 to 1um) imager designed to provide a three degree field-of-view with better than 0.2 arcsecond sampling. The image surface of the LSST is approximately 55cm in diameter with a curvature radius of 25 meters to flat. The detector format is currently defined to be a circular mosaic of 568 2k × 2k devices faceted to synthesize this surface within the constraints of LSST's f/1.25 focal ratio. This camera will provide over 2.2 Gigapixels per image with a 2 second readout time. With an expected typical exposure time of as short as 10s, this will yield a nightly data set on order of 3 terapixels. The scale of the LSST Instrument is equivalent to a square mosaic of 47k × 47k. The LSST Instrument will also provide a filter mechanism, as well as optical shuttering capability. Imagers of this size pose interesting challenges in many design areas including detectors, interface electronics, data acquisition and processing pipelines, dewar construction, filter and shutter mechanisms. Further more, the LSST 3 mirror optical system places this instrument in a highly constrained volume where these challenges are compounded. Specific focus is being applied to meeting defined scientific performance requirements with an eye to total cost, system complexity, power consumption, reliability, and risk. This paper will describe the current efforts in the LSST Instrument Concept Design.

The baseline design for the Large Synoptic Survey Telescope (LSST) requires a detector mosaic of over 2 Gigapixels covering a 55 cm diameter focal plane with 0.2 arcsec sampling. The camera and detector package for this telescope will benefit greatly by utilizing advanced concepts not normally required for astronomical telescope instrumentation. For the detector assembly, these concepts include low-cost, back illuminated CMOS or CCDs detectors with integrated electronic modules, curved detectors which would allow fewer but larger individual sensors, small pixels which maintain high MTF and full well capacity, anti-blooming techniques, fully-buttable packaging, and near room temperature operation. The camera may require a low thermal conductance gas-filled dewar to reduce atmosphere loading on the window, interchangeable and compact optical filters, and a flexible internal shutter. In this paper we discuss these issues relating to LSST focal plane technology.

CMOS-based imaging system-on-chip (i-SoC) technology is successfully producing large monolithic and hybrid FPAs that are superior in many respects to competing CCD-based imaging sensors. The hybrid approach produces visible 2048 by 2048 FPAs with <6 e- read noise and quantum efficiency above 80% from 400 nm to 920 nm; 4096 by 4096 mosaics are now being developed. The monolithic approach produces visible 12-bit imaging system-on-chips such as a 1936 by 1088 with higher quantum efficiency than mainstream CCDs, <25 e- read noise, <0.02% fixed pattern noise, automatic identification and replacement of defective pixels, black-level clamping, total power dissipation of only 180 mW, and various programmable features. Several successors having ≥12 Mpixels are in development. In both cases low-light-level performance is boosted by coupling the sensors to image intensifiers.

The optical design for the WIYN One Degree Imager (ODI) is based on well-known princples for the design of secondary focus correctors of Ritchey-Chrétien telescopes. It started as the classical two element plus/minus pair of lenses required to correct moderate and wide fields of view whilst working with wide spectral regions. However, since this corrector is required to cover a one degree square and plane field of view, accommodate filters and an atmospheric dispersion compensator, it evolved into three elements. In order to avoid the addition of more glass than was absolutely necessary the third element was designed to serve the dual function of field flattener and dewar window. The final form presented here is plus/minus/minus in power distribution with well-separated elements. The ADC is situated between the first and second elements with filter between the second and third elements in an accessible position. Theoretically the worst-case image given is 90% of the ensquared energy into 2 by 2 pixels in the corner of the one degree square field.

A 512×512 CMOS Active Pixel Sensor (APS) imager has been designed, fabricate, and tested for frontside illumination suitable for use in astronomy specifically in telescope guider systems as a replacement of CCD chips. The imager features a high-speed differential analog readout, 15 μm pixel pitch, 75 % fill factor (FF), 62 dB dynamic range, 315Ke- pixel capacity, less than 0.25% fixed pattern noise (FPN), 45 dB signal to noise ratio (SNR) and frame rate of up to 40 FPS. Design was implemented in a standard 0.5 μm CMOS process technology consuming less than 200mWatts on a single 5 Volt power supply. CMOS Active Pixel Sensor (APS) imager was developed with pixel structure suitable for both frontside and backside illumination holding large number of electron in relatively small pixel pitch of 15 μm. High-speed readout and signal processing circuits were designed to achieve low fixed pattern noise (FPN) and non-uniformity to provide CCD-like analog outputs. Target spectrum range of operation for the imager is in near ultraviolet (300-400 nm) with high quantum efficiency. This device is going to be used as a test vehicle to develop backside-thinning process.

We describe a new technique for ground-based telescopic surveys that can deliver a wide field of view and nearly diffraction-limited image quality. We discuss a very low cost, yet sensitive and efficient, concept to perform science previously considered from space. For ground-based telescopes with small D/r₀ (aperture over turbulence cell diameter) a significant improvement in point source sensitivity can be achieved with tip-tilt correction only. However, the solid angle over which image motion is constant is typically less than an arcminute. To achieve tip-tilt correction over a larger field we propose to use a high order adaptive optics system where one pupil sub-aperture now corresponds to one isokinetic patch. The high order deformable mirror is conjugated to an atmospheric height where the tip-tilt "beams" separate from each other while the overall tip-tilt can be taken out with a tip-tilt secondary mirror conjugated to low height. One source per square arcminute with V ≤ 18^m is required for the determination of the image motion, allowing a sky coverage of more than 50%. The improvement over seeing limited observations is maximal at D/r₀ ≈ 4 with a S/N improvement of a factor of four. An inexpensive system with 500 actuators can correct a field of view of 0.4 × 0.4 deg². It is thus well-suited for searches of point sources, e.g. high-z SN Ia or other transient phenomena.

The Echidna concept is an attractive solution to performing wide-field spectroscopy in fast beam systems (around F/2.5 or faster) where traditional pick and place multi-fiber positioners are not viable. We introduce a concept design for a 2000+ fiber Echidna-style positioner for the prime focus of a telescope optimized for wide field spectroscopy. A summary of the original 400-fiber Echidna positioner for the Subaru prime focus is presented. The natural extension of this design to a 2000+ fiber system is discussed. Two proposals currently under development incorporating such a positioner are introduced. The 2250 fiber Ukidna spectrograph is a stellar radical velocity engine for the UK Schmidt telescope at Siding Spring Observatory. More ambitious is the 4000 fiber Kilo-Aperture Optical Spectrograph (KAOS) enabling the 8-m Gemini telescopes with a 1.5° field of view for multi-object spectroscopy. Both instruments offer an order of magnitude increase in spectroscopic survey power compared with current day facilities.

The VIsible Replicable Ultra-cheap Spectrograph (VIRUS) is a multi-spectrograph made up of 64 individually small and simple “spectrographlets”. It represents a new approach to the design of a highly multiplexed spectrograph, offering the science multiplex advantage of ~10³ objects per exposure, coupled with the engineering multiplex advantage of ~10² spectrographs making up a whole. We argue that this is a cost-effective approach when compared to traditional spectrograph design, where each instrument is essentially a one-off prototype with heavy expenditure on engineering effort. In this paper we describe the conceptual design of VIRUS and compare its cost to conventional spectrographs.

UKIDSS is the next generation near-infrared sky survey. The survey will commence in early 2004, and over 7 years will collect 100 times as many photons as 2MASS. UKIDSS will use the UKIRT Wide Field Camera to survey 7500 square degrees of the northern sky, extending over both high and low Galactic latitudes, in JHK to K=18.5. This depth is three magnitudes deeper than 2MASS. UKIDSS will be the true near-infrared counterpart to the Sloan survey, and will produce as well a panoramic clear atlas of the Galactic plane. In fact UKIDSS is made up of five surveys and includes two deep extra-Galactic elements, one covering 35 square degrees to K=21, and the other reaching K=23 over 0.77 square degrees. This paper provides the details of the five UKIDSS surveys and describes the main science goals.

This paper describes the conceptual design for a near infrared camera for the Visible and Infrared Survey Telescope for Astronomy (VISTA). VISTA is a 4m class survey telescope that is being designed to perform pre-planned, ground-based astronomical surveys of the Southern sky from ESO's Cerro Paranal Observatory in Chile. The IR Surveys will be carried out in the J, H and K_short wave-bands at fainter magnitudes than those produced by the current generation of survey telescopes. To maximise throughput and survey efficiency, the camera has been completely integrated with the overall optical design with the telescope mirrors providing the power and the camera optics the wavefront correction. The camera design employs a non-traditional approach to control stray light by using cryogenic baffles rather than the more traditional cold-stop approach. The very large optical field available, 1.6° diameter with a plate scale of approximately 57μm/arcsec, means that the focal plane can accommodate sixteen 2k×2k IR detectors thus forming the largest IR focal plane used in ground based astronomy to date. The 67 Mpixel focal plane will generate a significant data rate. Each exposure will comprise 270 MB and a typical night will generate 400 GB.

Science is becoming very data intensive. Today's astronomy datasets with tens of millions of galaxies already present substantial challenges for data mining. In less than 10 years the catalogs are expected to grow to billions of objects, and image archives will reach Petabytes. Imagine having a 100GB database in 1996, when disk scanning speeds were 30MB/s, and database tools were immature. Such a task today is trivial, almost manageable with a laptop. We think that the issue of a PB database will be very similar in six years. In this paper we scale our current experiments in data archiving and analysis on the Sloan Digital Sky Survey data six years into the future. We analyze these projections and look at the requirements of performing data mining on such data sets. We conclude that the task scales rather well: we could do the job today, although it would be expensive. There do not seem to be any show-stoppers that would prevent us from storing and using a Petabyte dataset six years from today.

The Sloan Digital Sky Survey (SDSS) data handling presents two challenges: large data volume and timely production of spectroscopic plates from imaging data. A data processing factory, using technologies both old and new, handles this flow. Distribution to end users is via disk farms, to serve corrected images and calibrated spectra, and a database, to efficiently process catalog queries. For distribution of modest amounts of data from Apache Point Observatory to Fermilab, scripts use rsync to update files, while larger data transfers are accomplished by shipping magnetic tapes commercially. All data processing pipelines are wrapped in scripts to address consecutive phases: preparation, submission, checking, and quality control. We constructed the factory by chaining these pipelines together while using an operational database to hold processed imaging catalogs. The science database catalogs all imaging and spectroscopic object, with pointers to the various external files associated with them. Diverse computing systems address particular processing phases. UNIX computers handle tape reading and writing, as well as calibration steps that require access to a large amount of data with relatively modest computational demands. Commodity CPUs process steps that require access to a limited amount of data with more demanding computations requirements. Disk servers optimized for cost per Gbyte serve terabytes of processed data, while servers optimized for disk read speed run SQLServer software to process queries on the catalogs. This factory produced data for the SDSS Early Data Release in June 2001, and it is currently producing Data Release One, scheduled for January 2003.

The SDSS project has taken 5-band data covering approximately 3000 deg², or 4Tby of data. This has been processed through a set of image-processing pipelines, and the resulting catalogues of about 100 million objects have been used for a number of scientific projects. We discuss our software infrastructure, and outline the architecture of the SDSS image processing pipelines. In order to process this volume of data the pipelines have to be robust and reasonably fast; because we have been interested in looking for rare objects, the number of outliers due to deficiencies in the data and bugs in the software must be small. We have found that writing the codes has been one of the harder and more expensive aspects of the entire survey.

Over a 5-year observing period, the Sloan Digital Sky Survey (SDSS) will acquire data to construct a digital 5-color photometric map of the Northern Galactic sky to about 23^rd magnitude, and a correspondingly large and homogeneous spectroscopic survey. The SDSS is in a unique class of projects, in that all aspects of the SDSS infrastructure, from the telescopes and instruments, to software and operations staffing, were designed and assembled specifically to conduct this Survey. To ensure success, observing operations are run in production mode and performance metrics are used to measure progress over time. The methodology of preparing the performance baseline plan, and an assessment of Survey progress after two full years of operation, are reviewed and some lessons learned discussed. In particular, the SDSS has benefited greatly by asking peers in the field to participate in external reviews that periodically assess performance and offer independent, fresh views of potential areas of concerns. Additionally, difficulties caused by the absence of an experienced systems-engineering staff during the final phase of construction and commissioning are reviewed. The challenges of building a production machine out of complex and state-of-the-art sub-systems cannot be overstated. In the case of the SDSS, insufficient systems engineering led to problems meeting initial image quality requirements, primarily because of problems with the thermal performance of the telescope and its environment. A concerted campaign to deal with these issues was successful, but that success came rather later than we would have liked. The improvements made to address the situation, and the resulting increase in operational performance, are discussed.

In recent years massive CCD photometry has dramatically increased the number of known variable stars in the Milky Way and nearby galaxies of the Local Group. Some surveys are related to microlensing studies, distance determinations and the study of Cepheids and other pulsating stars, and are based on relatively small telescopes. The comparison of the performances of the various instruments shows the present limitations of the variable star research, and the requirements are to increase the sensitivity, spatial resolution and field of view. In order to get a better sensitivity, we adopted the Wh-photometry, or unfiltered observations. We discuss the merits and defects of this technique in the context of recent studies with the ESO 0.9m Dutch telescope and Wide Field Imager at the 2.2 m telescope. As regards the high precision photometry, we remark that a better control of the various error sources (including the stability of the instrumentation) is needed in order to detect very small amplitude variations with good confidence.

We compare the efficiencies of a relational database, MySQL, and an object oriented database, Objectivity, for simple functionalities, like handling data produced by a reduction pipeline. For each test, we then challenge two designs as similar as possible, both capable to handle the same amount of useful data, and which both have the same functionalities implemented on top of the design. From this study, we then discuss which system is more suited or more efficient for these types of applications. In particular, the impact of the design on the global application efficiency is addressed, as well as the advantages and limitations of the two systems. The tests show that relational system are more efficient for simple queries. The absence of a global query syntax for object oriented database turns out to be a disadvantage when dynamic behavior is needed or required. Moreover, it implies an additional effort in API (Application Programming Interface) development, which reduces the strength of object oriented system when handling complex data structure and related queries.

The era of large survey datasets has arrived, and the era of large survey telescope projects is upon us. Many of these new telescope projects will not only produce large datasets, they will produce datasets that require real-time astronomical analysis, including object detection, photometry, and classification. These datasets promise to open new horizons in the exploration of the time domain in astrophysical systems on large scales. But to fulfill this promise, the projects must design and develop data management systems on a much larger scale (many Terabytes per day continuously) than has previously been achieved in astronomy. Working together, NOAO and the University of Washington are developing prototype pipeline systems to explore the issues involved in real-time time-variability analysis. These efforts are not simply theoretical exercises, but rather are driven by NOAO Survey programs which are generating large data flows. Our survey projects provide a science-driven testbed of data management strategies needed for future initiatives such as the Large Synoptic Survey Telescope and other large-scale astronomical data production systems.

The Capodimonte Deep Field (OACDF) is a multi-colour imaging survey on two 0.5×0.5 square degree fields performed in the BVRI bands and in six medium-band filters (700 - 900 nm) with the Wide Field Imager (WFI) at the ESO 2.2 m telescope at La Silla, Chile. In this contribution the adopted strategies for the OACDF data reduction are discussed. Preliminary scientific results of the survey are also presented.

The UKIRT Wide Field Camera (WFCAM) is an IR mosaic camera that represents an enormous leap in deep IR survey capability. It will be used as both an open time facility, and to perform a public IR Deep Sky Survey (the UKIDSS project), starting in early 2004. Here we present current plans for the data archive system, which will be provided as a standard service for all UK WFCAM data whether private or public survey data. The data rate is an order of magnitude larger than any previous survey experiment. WFCAM is therefore a crucial stepping stone between current day surveys such as SuperCOSMOS, APM and SDSS, and future facilities such as VISTA and the LSST. Pipeline processing presents a technical challenge, but the strongest challenges come in operation and curation of such a pipeline and of the rapidly accumulating database. For the public archive, there is little technical challenge in simply storing the data, and the real challenge comes in the rapidly increasing expectations of the user community for the kind of on-line services available with the archive. We describe three levels of archive service and the challenges they present, and discuss the hardware and software solutions we are likely to deploy.

The current status and future developments of highly accurate, dense, astrometric surveys on the International Celestial Reference System (ICRS) are discussed. The U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project is an ongoing, observational program aiming at a global sky coverage with 20 to 70 mas positional accuracy for the 10 to 16 mag range. This program extends the reference star density by a factor of about 30 over the Tycho-2 catalog, with about 10 times higher positional accuracy than the GSC I. The second UCAC release fall 2002) gives positions and proper motions for stars between -90 and about +40 degrees declination. The first release and unpublished updates have been supporting the Sloan Digital Sky Survey, 2MASS, the minor planet community, and SOAR. The next step, a 1-meter class, dedicated, robotic, wide-field, astrometric instrument is already designed (10k by 10k single CCD) and a global sky catalog to 20th magnitude could be observed in only 2 years with 10 mas accurate positions in the magnitude range between 15 to 18.

The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) will improve range measurements to the moon by at least an order-of-magnitude, with the goal of achieving millimeter precision. Lunar ranging provides the most stringent tests of Einstein's strong equivalence principle, as well as placing the tightest constraints on the time evolution of Newton's gravitational constant. At the heart of APOLLO is an integrated array of avalanche photodiodes (APDs) developed at MIT Lincoln Laboratories. These devices are capable of detecting the arrival of a single photon with high temporal precision (< 100 ps), with detection efficiencies as high as 50%. The thin APD arrays have breakdown voltages in the neighborhood of 25 volts, active areas 20, 30, or 40 microns in diameter, placed on 100 micron centers in a square pattern. APOLLO will initially work with a 4×4 array, but may eventually upgrade to a larger format. The potential use of APD array technology in other areas of astronomy is briefly discussed.