This PDF file contains the front matter associated with SPIE Proceedings Volume 7017, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

The Advanced Technology Solar Telescope (ATST) project is near the end of its design and development phase and ready to begin construction. This paper describes the current status of ATST and a few of the lessons learned during design and development from a systems-engineering perspective. It highlights some of the important differences between nighttime and daytime solar observing with emphasis on the resulting impacts on telescope design and operational concepts. We have had to adopt somewhat non-standard primary mirror polish specifications to support our requirement to observe the sun's corona very close to solar limb. Our suite of image-quality error budgets are examined to show the progression of system requirements that are derived from each use case, and the value of Monte Carlo simulations as a means of controlling user expectations. We discuss PDMWorks® Enterprise and other elements of our configuration management system as well as the tools we have developed (and are developing) to document the requirements flow-down and to establish a trace-back mechanism. We expect to use this trace-back capability during contract negotiations and later in the fabrication process to quickly assess the potential impact of any exceptions to our specifications that may be requested by our vendors.

A large ground-based astronomical telescope project, like the Thirty Meter Telescope (TMT), is rivaling space projects in technical complexity, design and construction time span, budget, as well as organizational diversity and geographical distribution. A unique challenge in large ground based projects is implementing appropriate systems engineering methods and tools in the absence of the strong institutional backdrop that space projects can rely on. This paper provides a critical overview of the established system engineering practice in the TMT project, including requirements engineering, document and configuration control, as well as performance allocation and estimation. In particular, we introduce a new performance metric, the Point Source Sensitivity (PSS), and show how it is superior to the 80% enclosed energy diameter measure. The overall strategy for estimating the performance of TMT is outlined, showing how the various elements of performance modeling, reported in detail in other papers, fit together to provide a probabilistic assessment of the achievable image quality of the observatory. An overview of the estimated system performance is presented with critical analysis of the major factors limiting the seeing limited observations.

We survey the current status of the modelling and simulation process and its resulting products in current day groundbased astronomical instrument developments whilst highlighting the areas where improvements can be made. There follows a description of a novel integrated systems approach for modelling, as used by the European Extremely Large Telescope (E-ELT) EAGLE instrument team for the development of a Multi-Object Infrared Spectrometer. Also illustrated in this paper is how to use and record the simulation results early in the development cycle of an instrument in such a way as to contribute to the verification of the overall instrument performance.

Efficient assignment of science targets to the individual channels of a multi-object astronomical instrument, such as EAGLE for the European Extremely Large Telescope (E-ELT), is crucial for maximising the utility of the instrument. This paper presents the results obtained by modelling the efficiencies of various pick-off system concepts: free standing Pick-Off Mirrors (POMs), POMs at the tip of moving arms, or a tiled focal plane. Consideration is also taken of the way in which the freestanding POMs are placed: by a pick and place robot, or a swarm of micro autonomous robots. Allocation algorithms were developed for each concept and applied to target fields which are representative of EAGLE's likely science cases. It is shown how the results of the modelling were used to generate a new system comparison criterion called Allocation Flexibility and how this influences the choice of the baseline solution. The allocation flexibility suggests that the best system will use free standing POMs with as small a footprint as possible, which reflect light to a raised beam steering mirror.

The heart of the KMOS instrument is a complex optical system with over 300 separate optical paths. The optical design is spread between 4 sub-systems which have been designed at three different institutions. In order that the end to end performance of the final design can be monitored and controlled it is necessary to specify the performance and interface requirements of each sub-system clearly. This paper describes the parameters that were necessary to control so that the sub-system designs could be carried out independently while maintaining visibility and control of the end to end performance. The method of apportioning the budgets between the sub-systems and the modeling performed to verify compliance is also described.

This paper elaborates the system engineering methods that are being successfully employed within the European Consortium (EC) to deliver the Optical System of the Mid Infa-Red Instrument (MIRI) to the James Webb Space Telescope (JWST). The EC is a Consortium of 21 institutes located in 10 European countries and, at instrument level, it works in a 50/50 partnership with JPL who are providing the instrument cooler, software and detector systems. The paper will describe how the system engineering approach has been based upon proven principles used in the space industry but applied in a tailored way that best accommodates the differences in international practices and standards with a primary aim of ensuring a cost-effective solution which supports all science requirements for the mission. The paper will recall how the system engineering has been managed from the definition of the system requirements in early phase B, through the successful Critical Design Review at the end of phase C and up to the test and flight build activities that are presently in progress. Communication and coordination approaches will also be discussed.

On the James Webb Space Telescope (JWST), the Mid-Infrared Instrument (MIRI) is unique among the four science instruments in that it operates around 7K as opposed to 40K like the other three near infrared instruments. Remote cooling of the MIRI is achieved through the use of a Joule-Thomson (J-T) Cooler, which is precooled by a multistage Pulse Tube Cooler. The MIRI Cooler systems engineering is elaborate because the Cooler spans a multitude of regions in the observatory that are thermally and mechanically unique with interfaces that encompass a number of different organizations. This paper will discuss how a significant change to the MIRI Cooling System from a solid hydrogen Dewar to a Cooler was achieved after the instrument Preliminary Design Review (PDR), and it will examine any system compromises or impacts that resulted from this change so late in the instrument design. A general overview of the Dewar and the Cooler systems management, the roles of the systems teams in the different organizations, how the requirements are managed in such an elaborate environment, and the distinct design and Integration and Test (I&T) challenges will also be provided.

The WISE observatory contains solid hydrogen to achieve cooling, which precludes many of the "test as you fly" (TAYF) methods for the integration and test of the WISE flight system due to the hazardous nature of the solid hydrogen. Additionally, there is reluctance to remove the optical cover after integration to the spacecraft due to increased risk. This paper discusses the WISE approach to verification and validation (V&V) given these constraints. As payloads increase in size and complexity more missions will necessarily deviate from the TAYF approach. The WISE system combines full testing of the instrument while the fight system uses an interment simulator for many of the flight system environmental tests. The test planning, simulator design, and the analyses which indicate why this would be a low-risk V&V approach for the WISE mission are discussed.

The effects of alignment perturbations on the aberration fields of two mirror astronomical telescopes are discussed. It is demonstrated that expressions describing alignment induced field-linear astigmatism, published by McLeod based on the work of Schroeder, can be obtained using nodal aberration theory. Rather than merely providing a different derivation for alignment induced astigmatism, it is shown that nodal theory can provide several insights that are significant for the development of effective alignment techniques. In the example of a specific telescope sited on Mt. Hopkins (Ritchey- Chretien), two approaches to identify misalignments of the secondary mirror are demonstrated. One approach utilizes the eccentricity of defocused star images and their orientation angles to calculate the misalignment of the secondary mirror after axial coma is removed. A second approach based on the location of the two zeros of the astigmatic aberration field is then shown to give equivalent results, but at the same time ensuring a complete model of all possible effects of misalignment on the performance of the telescope.

The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems Company in Sunnyvale, CA is designed for the verification and testing of optical systems. The facility consists of a large, temperature stabilized vacuum chamber that also functions as a class 10k cleanroom. Within this chamber and atop an advanced vibration-isolation bench are the 6.5 meter diameter LOTIS Collimator and Scene Generator, LOTIS alignment and support equipment. The optical payloads are also placed on the vibration bench in the chamber for testing. The Scene Generator is attached to the Collimator forming the Scene Projection System (SPS) and this system is designed to operate in both air and vacuum, providing test imagery in an adaptable suite of visible/near infrared (VNIR) and midwave infrared (MWIR) point sources, and combined bandwidth visible-through-MWIR point sources, for testing of large aperture optical payloads. The heart of the SPS is the LOTIS Collimator, a 6.5m f/15 telescope, which projects scenes with wavefront errors <85 nm rms out to a ±0.75 mrad field of view (FOV). Using field lenses, performance can be extended to a maximum field of view of ±3.2 mrad. The LOTIS Collimator incorporates an extensive integrated wavefront sensing and control system to verify the performance of the system, and to optimize its actively controlled primary mirror surface and overall alignment. Using these optical test assets allows both integrated component and system level optical testing of electro-optical (EO) devices by providing realistic scene content. LOTIS is scheduled to achieve initial operational capability in 2008.

The Atacama Large Millimeter/submillimeter Array (ALMA) is the largest astronomical ground based global collaboration. The project is a partnership of organisations and institutes located in four continents, each bringing its own organisational structures, scientific objectives, and management. This brings a richness of different experiences and expertise to the project, but is also a challenge to build and provide the public and the science users a unified project. In this talk we will review the ALMA organisation and management structure, its successes, difficulties and experience gained for future projects of similar complexity and challenge.

TMT is a big science project and its scale is greater than previous ground-based optical/infrared telescope projects. This paper will describe the ideal "linear" project and how the TMT project departs from that ideal. The paper will describe the needed adaptations to successfully manage real world complexities. The progression from science requirements to a reference design, the development of a product-oriented Work Breakdown Structure (WBS) and an organization that parallels the WBS, the implementation of system engineering, requirements definition and the progression through Conceptual Design to Preliminary Design will be summarized. The development of a detailed cost estimate structured by the WBS, and the methodology of risk analysis to estimate contingency fund requirements will be summarized. Designing the project schedule defines the construction plan and, together with the cost model, provides the basis for executing the project guided by an earned value performance measurement system.

Previous studies of the scaling of the costs of ground based optical observatories suggest that total costs scale as the primary mirror diameter to a power between 1.7 and 3.0. It has been suggested that observatory costs may scale as primary mirror diameter squared reflecting the dependence on thinner mirrors in the current generation of observatory design. Upon completing the detailed cost estimate in support of the Preliminary Design for the Thirty Meter Telescope, an in depth study was undertaken to understand the sensitivity of the estimate to mirror diameter and thickness in addition to other leading parameters of TMT such as segmentation, primary focal ratio, and enclosure diameter. Based upon this analysis, and expressing the costs scaled solely to the mirror diameter, our analysis suggests that the TMT design scales effectively as the diameter to the power 1.2. We will describe the assumptions used to guide this study, the methods used to build the cost model, and the general results of the model.

The SPHERE is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the vicinity of bright stars and to characterize them through spectroscopic and polarimetric observations. It is built by a consortium of 11 institutes from five countries. Rather than a traditional instrument, it is a complete system with a core made of an extreme-Adaptive Optics (AO) turbulence correction, pupil tracker and interferential coronagraphs feeding 3 different science instruments: working in Near Infrared Y, J, H and Ks bands (0.95 - 2.32μm) and in visible (0.5 - 0.9μm) light. In this paper, we focus on project organization matters like the make-up of the consortium and the decision flow. We try to identify if the management is adequate to the size and scope of the project and the consortium that is in charge of developing it. Our view regarding the organization of future multi-site complex fast track projects are presented.

WISE is a NASA MIDEX mission to survey the entire sky in four bands from 3 to 25 microns with sensitivity about 500 times greater than the IRAS survey. WISE will find the most luminous galaxies in the universe, find the closest stars to the Sun, and detect most of the main belt asteroids larger than 3 km. WISE launch is scheduled in November, 2009 on a Delta 7320-10 to a 525 km Sun-synchronous polar orbit. This paper gives an overview of WISE including development status and management approach. WISE flight system design is single string with selected redundancy and graceful degradation. Wherever possible, design heritage from prior missions is pursued and properly reviewed to reduce development time and cost. Further risk reduction is achieved since the WISE spacecraft has no deployable mechanisms and no propulsion. Nonetheless, a complex space mission with a sophisticated cryogenic IR telescope such as WISE demands a partnership of multiple organizations in government research, academia, and industry. With a cost cap and relatively short development schedule, it is essential for all WISE partners to work seamlessly together. This is accomplished by a single management team representing all key partners and disciplines in science, systems engineering, mission assurance, project and contract management. WISE uses a variety of management tools including frequent team interaction, schedule, milestone and critical path analysis, risk analysis, reliability analysis, earned value analysis, configuration management, and management of schedule and budget reserves. After a successful mission critical design review in June, 2007, WISE has completed building most of the flight hardware, and started integration and test within payload and spacecraft.

The Mid-Infrared Instrument (MIRI) of the James Webb Space Telescope (JWST) is developed in a partnership between JPL and a large European Consortium (EC) for delivery via ESA to the JWST project at NASA's Goddard Space Flight Center (GSFC). The four parties have created an effective management and system engineering structure to deal with distributed and international management, system engineering, and testing teams. This paper describes the organizational and team structure created to manage and develop MIRI in an efficient and productive manner. This paper also addresses the challenges and subsequent solutions for merging sometimes disparate cultures and approaches to managing technical programs.

Telescope enclosures are used to limit the disturbance caused by the wind on the pointing and tracking performances of telescopes and to preserve primary mirror optical shape. Within the framework of the EC program "ELT Design Study - Contract No. 011863", extended wind tunnel test have been performed to characterize wind turbulent structure inside two different types of enclosures and with different wind screen positions. Also Power Spectral Densities of the turbulent flow have been directly measured. In this paper the results are summarized, together with the limitations associated to the use of scaled models. Mean speed distributions and turbulent energy distributions have been measured. The results are compared with the fields determined with quasisteady approach based on existing turbulence models (namely von Karman). Measurements obtained on the field in the VST enclosure at Paranal are crossed checked with the results obtained in the Boundary Layer wind tunnel.

Cylindrical (carousel) and spherical dome designs for the Large Synoptic Survey Telescope (LSST) were analyzed for air flow characteristics using computational fluid dynamic models. The primary objective was to determine the level of dome flushing achieved with natural ventilation and representative site wind conditions. The domes were 30 meters in diameter at the base, designed to enclose the LSST and provide adequate space for servicing requirements with the smallest possible major dimensions. The carousel style enclosure allowed moderately superior flushing with better uniformity which will produce superior local seeing conditions. Since the cylindrical style enclosure was also determined to be less costly, this concept was chosen as the baseline enclosure design for the LSST.

The performance requirements of the Thirty Meter Telescope (TMT) dictate, among others, a thorough understanding of the flow field inside and around the observatory. Mirror and dome seeing as well as dynamic wind loading on the optics, telescope structure and enclosure constitute significant sources of image degradation. A summary of the current status of Computational Fluid Dynamics (CFD) simulations for TMT is presented, with special attention given to the choice of thermal boundary conditions. Detailed simulations of the mirror support assemblies determine the direction of heat flow from important heat sources and provide feedback to the design. They also provide estimates of the heat transfer coefficients for the solid thermal models. A transient radiation model has also been developed for the enclosure and telescope surfaces in order to estimate the heat flux exchange with the air volume. It also provides estimates of the effective emissivity for the solid thermal models. Finally, a complete model of the observatory on a candidate summit is used to calculate air velocity, pressure and temperature for a matrix of given telescope orientations and enclosure configurations. Calculated wind velocity spectra above M1 and around M2 as well as the wind force on the enclosure are used as inputs in the TMT integrated dynamic model. The temperature and flux output of the aforementioned thermal models are used as input surface boundary conditions in the CFD model. Generated records of temperature variations inside the air volume of the optical paths are fed into the TMT thermal seeing model.

Mirror and dome seeing are critical effects influencing the optical performance of ground based telescopes. The Thirty Meter Telescope project has been utilizing a combination of optical simulations and Computational Fluid Dynamics to model the dome and mirror seeing. A set of optical modeling tools has been developed in MATLAB to post-process high spatial resolution thermal CFD results and calculate image degradation due to dome seeing and mirror seeing. The same tools can provide the distribution of seeing contribution along optical path in order to recognize potential problems and guide the observatory design. The method, including limiting assumptions for the optical modeling tools are discussed.

Integrated models including optics, structures, control systems, and disturbances are important design tools for Extremely Large Telescopes (ELTs). An integrated model has been formulated for the European ELT and it includes telescope structure, main servos, primary mirror segment control system, wind, optics, wavefront sensors, deformable mirror, and an AO reconstructor and controller. There are three model phases: Initialization, execution of a solver to determine time responses, and post-processing. In near future, the model will be applied for performance studies and design trade-offs for the European ELT.

We investigate a new metric, Normalized Point Source Sensitivity (PSSN), for characterizing the seeing limited performance of the Thirty Meter Telescope. As the PSSN metric is directly related to the photometric error of background limited observations, it truly represents the efficiency loss in telescope observing time. The PSSN metric properly accounts for the optical consequences of wavefront spatial frequency distributions due to different error sources, which makes it superior to traditional metrics such as the 80% encircled energy diameter. We analytically show that multiplication of individual PSSN values due to individual errors is a good approximation for the total PSSN when various errors are considered simultaneously. We also numerically confirm this feature for Zernike aberrations, as well as for the numerous error sources considered in the TMT error budget using a ray optics simulator, Modeling and Analysis for Controlled Optical Systems. We also discuss other pertinent features of the PSSN including its relations to Zernike aberration and RMS wavefront error.

We consider high-resolution optical modeling of the Thirty Meter Telescope for the purpose of error budget and instrumentation trades utilizing the Modeling and Analysis for Controlled Optical Systems tool. Using this ray-trace and diffraction model we have simulated the TMT optical errors related to multiple effects including segment alignment and phasing, segment surface figures, temperature, and gravity. We have then modeled the effects of each TMT optical error in terms of the Point Source Sensitivity (a multiplicative image plane metric) for a seeing limited case and an adaptive optics corrected case (for the NFIRAOS). This modeling provides the information necessary to rapidly conduct design trades with respect to the planned telescope instrumentation and to optimize the telescope error budget.

This presentation describes a strategy for assessing the performance of the Thirty Meter Telescope (TMT). A Monte Carlo Simulation Framework has been developed to combine optical modeling with Computational Fluid Dynamics simulations (CFD), Finite Element Analysis (FEA) and controls to model the overall performance of TMT. The framework consists of a two year record of observed environmental parameters such as atmospheric seeing, site wind speed and direction, ambient temperature and local sunset and sunrise times, along with telescope azimuth and elevation with a given sampling rate. The modeled optical, dynamic and thermal seeing aberrations are available in a matrix form for distinct values within the range of influencing parameters. These parameters are either part of the framework parameter set or can be derived from them at each time-step. As time advances, the aberrations are interpolated and combined based on the current value of their parameters. Different scenarios can be generated based on operating parameters such as venting strategy, optical calibration frequency and heat source control. Performance probability distributions are obtained and provide design guidance. The sensitivity of the system to design, operating and environmental parameters can be assessed in order to maximize the % of time the system meets the performance specifications.

Dynamic disturbance sources affecting the optical performance of the Thirty Meter Telescope (TMT) include unsteady wind forces inside the observatory enclosure acting directly on the telescope structure, unsteady wind forces acting on the enclosure itself and transmitted through the soil and pier to the telescope, equipment vibration either on the telescope itself (e.g. cooling of instruments) or transmitted through the soil and pier, and potentially acoustic forces. We estimate the characteristics of these disturbance sources using modeling anchored through data from existing observatories. Propagation of forces on the enclosure or in support buildings through the soil and pier to the telescope base are modeled separately, resulting in force estimates at the telescope pier. We analyze the resulting optical consequences using integrated modeling that includes the telescope structural dynamics, control systems, and a linear optical model. The dynamic performance is given as a probability distribution that includes the variation of the external wind speed and observing orientation with respect to the wind, which can then be combined with dome seeing and other time- or orientation-dependent components of the overall error budget. The modeling predicts acceptable dynamic performance of TMT.

This paper is part five of a series on the ongoing optical modeling activities for the James Webb Space Telescope (JWST). The first two papers discussed modeling JWST on-orbit performance using wavefront sensitivities to predict line of sight motion induced blur, and stability during thermal transients. The third paper investigates the aberrations resulting from alignment and figure compensation of the controllable degrees of freedom (primary and secondary mirrors), which may be encountered during ground alignment and on-orbit commissioning of the observatory, and the fourth introduced the software toolkits used to perform much of the optical analysis for JWST. The work here models observatory operations by simulating line-of-sight image motion and alignment drifts over a two-week period. Alignment updates are then simulated using wavefront sensing and control processes to calculate and perform the corrections. A single model environment in Matlab is used for evaluating the predicted performance of the observatory during these operations.

The James Webb Space Telescope (JWST) Observatory is the successor mission to the Hubble Space Telescope and will lead to great scientific advancements in near- and mid-infrared astronomy. One of the four science instruments on board the spacecraft is NIRSpec, which is being developed by the European Space Agency (ESA) with EADS Astrium Germany GmbH as the prime contractor. This multi-object spectrograph will be able to measure the spectra of at least 100 objects simultaneously in the near infrared wavelength range from 0.6µm to 5.0µm and at various spectral resolutions. In order to assess the performance of the instrument, a simulator has been developed to calculate key characteristics of the optical design and the final instrument output. It uses Fourier Optics with wavefront error maps to predict the point spread function on the Micro Shutter Assembly (MSA) and the detector and can include real, as measured, spectral data of filters and dispersive elements. With the implementation of parameterized image distortion and detector features, it is possible to obtain full realistic detector frames for any optical input. Still the computation time is comparably short. The program will be of great use to predict and verify response of NIRSpec during the test and calibration campaigns.

The future James Webb space telescope (JWST), developed jointly by the American, European and Canadian space agencies (NASA, ESA and CSA), is scheduled for launch in 2013. Among its instrument suite, the spectrograph NIRSpec will provide astronomers with multi-object, integral-field and classical slit spectrographic capabilities in the near-infrared (0.6-5.0 μm). NIRSpec is being built by EADS Astrium for ESA and it was quickly realized that given the complexity of the instrument, it was necessary to develop dedicated software for the modeling of its performances. In this context, the Centre de Recherche Astrophysique de Lyon (CRAL) is responsible of the development of the so-called NIRSpec instrument performance simulator (IPS) that will serve as a basis for early performance verification purposes; provide inputs and support for the verification and calibration campaigns, as well as for the development of the instrument calibration, target acquisition and data reduction procedures. In this paper, we present the IPS software itself, emphasizing its capability to generate simulated NIRSpec detector exposures for the various modes of the instrument (multi-object, integral field unit, fixed slits) and for a large variety of situations (test, calibration, scientific observations...). We will also show simulations results.

The Multi Unit Spectroscopic Explorer (MUSE) instrument is a second-generation integral-field spectrograph in development for the Very Large Telescope (VLT), operating in the visible and near IR wavelength range (465-930 nm). Given the complexity of MUSE we have developed a numerical model of the instrument, which includes the whole chain of acquisition from the atmosphere down to the telescope and including the detectors, and taking into account both optical aberrations and diffraction effects. In this paper we present the software, discuss the problems that have been encountered and the solutions that have been implemented, and we conclude by presenting examples of simulations.

The Gemini Planet Imager (GPi) is comprised of three main opto-mechanical systems: the Adaptive Optics (AO) system, the Calibration (CAL) system, and the Integral Field Spectrograph (IFS). Each of these subsystems are built and aligned independently, and then integrated into the final instrument. A truss framework called the Flexure Sensitive Structure (FSS) has been designed to locate each optical subsystem within the instrument, utilizing kinematic bipods to eliminate distortion due to flexure and thermal changes. Due to the distributed nature of the optical system, an end-to-end opto-mechanical modeling approach is taken using the NRC Integrated Model (NRCIM). This set of numerical tools was originally developed to support the Canadian VLOT and TMT telescope studies. The instrument structural response is calculated using a commercial finite element package; and the 6 degree-of-freedom rigid body motions of the optical elements are then passed to an optical model. Ray-tracing is performed to determine the line-of-sight errors at numerous critical focal planes and pupil planes. Disturbances to the system include gravity induced flexure and thermal distortions. Optical compensation using a combination of closedloop feedback and open-loop models are then applied using steering mirrors to improve the line-of-sight figures of merit. Finally, these figures of merit are compared against the system optical error budget to assess the overall performance of the opto-mechanical system.

The core of the High Frequency Instrument (HFI) on-board the Planck satellite consists of 52 bolometric detectors cooled at 0.1 Kelvin. In order to achieve such a low temperature, the HFI cryogenic architecture consists in several stages cooled using different active coolers. These generate weak thermal fluctuations on the HFI thermal stages. Without a dedicated thermal control system these fluctuations could produce unwanted systematic effects, altering the scientific data. The HFI thermal architecture allows to minimise these systematic effects, thanks to passive and active control systems described in this paper. The passive and active systems are used to damp the high and low frequency fluctuations respectively. The results of the simulation of these active and passive control systems are presented here. These simulations based on the use of thermal transfer functions for the thermal modelling can then be used for finding the optimal working point of the HFI PID active thermal control system.

The primary mirror control system (M1CS) keeps the 492 segments of the Thirty Meter Telescope primary mirror aligned in the presence of disturbances. A global position control loop uses feedback from inter-segment edge sensors to three actuators behind each segment that control segment piston, tip and tilt. If soft force actuators are used (e.g. voice-coil), then in addition to the global position loop there will be a local servo loop to provide stiffness. While the M1 control system at Keck compensates only for slow disturbances such as gravity and thermal variations, the M1CS for TMT will need to provide some compensation for higher frequency wind disturbances in order to meet stringent error budget targets. An analysis of expected high-wavenumber wind forces on M1 suggests that a 1Hz control bandwidth is required for the global feedback of segment edge-sensorbased position information in order to minimize high spatial frequency segment response for both seeing-limited and adaptive optics performance. A much higher bandwidth is required from the local servo loop to provide adequate stiffness to wind or acoustic disturbances. A related paper presents the control designs for the local actuator servo loops. The disturbance rejection requirements would not be difficult to achieve for a single segment, but the structural coupling between segments mounted on a flexible mirror cell results in controlstructure interaction (CSI) that limits the achievable bandwidth. Using a combination of simplified modeling to build intuition and the full telescope finite element model for verification, we present designs and analysis for both the local servo loop and global loop demonstrating sufficient bandwidth and resulting wind-disturbance rejection despite the presence of CSI.

Thermal analysis for the Thirty Meter Telescope (TMT) optics (the primary mirror segment, the secondary mirror, and the tertiary mirror) was performed using finite element analysis in ANSYS and I-DEAS. In the thermal analysis, each of the optical assemblies (mirror, mirror supports, cell) was modeled for various thermal conditions including air convections, conductions, heat flux loadings, and radiations. The thermal time constant of each mirror was estimated and the temperature distributions of the mirror assemblies were calculated under the various thermal loading conditions. The thermo-elastic analysis was made to obtain the thermal deformation based on the resulting temperature distributions. The optical performance of the TMT optics was evaluated from the thermally induced mirror deformations. The goal of this thermal analysis is to establish thermal models by the FEA programs to simulate for an adequate thermal environment. These thermal models can be utilized for estimating the thermal responses of the TMT optics. In order to demonstrate the thermal responses, various sample time-dependent thermal loadings were modeled to synthesize the operational environment. Thermal responses of the optics were discussed and the optical consequences were evaluated.

X-shooter is a high-efficiency spectrograph capable of simultaneously observing the complete spectral range of 300- 2500 nm. The instrument will be located at the Cassegrain focus of one of the VLT UTs. To allow sky back ground limited observations the 120 kg Optical Bench of the NIR Spectrograph and the HAWAII-2RG detector are cooled to 105 K and 82 K respectively. To ensure vibrationless operation the cooling is performed by a LN2 bath-cryostat. The thermal stability requirements for the Optical Box are very tight (order of 100 mK) considering that the NIR-cryostat is subject to telescope movement and LN2 level variations. Large glass optics are limiting the cooldown. To speed up the cooldown the cooling concept of the Optical Box includes the utilization of LN2 heat exchangers. To avoid asymptotic stabilizing times the Optical Box is cooled below the operating temperature. When the optics reach a temperature slightly above the operating temperature the temperature of the Optical Box is quickly brought back to stabilize the optics. Dedicated controllers, strapping and heaters are used for temperature stabilization during steady state. A cryostat hold time of 24 hours with the minimum amount of LN2 in view of the tight mass budget requires strict control of the power budget and careful control of the design margins. This is ensured by precise modeling of the temperature behavior. The thermal model is compared with the actual measured thermal behavior.

We have performed finite element thermal analysis of our 6.5 meter primary mirror in the hopes of improving the accuracy of our open loop models and reducing the need to interrupt science observations to tune our optics. In the analysis we apply temperature variations to the front, back, and middle of the mirror to correspond to the locations of installed thermocouples. The input temperature variations and the predicted steady-state surface distortions are modeled as Zernike polynomials. The most significant effect we find is the focus error generated by a temperature gradient between the front and back of the mirror. Comparison with wavefront sensor data shows that we can get reasonably good agreement between predicted and measured focus errors. However, we do not yet get good agreement for other, higher order terms. There is also poorer agreement when conditions are changing rapidly.

The exterior of the Advanced Technology Solar Telescope enclosure requires cooling to eliminate so-called external dome seeing caused by solar loading during the observing day. This is achieved by way of coolant circulation through external plate coil panels, thereby maintaining the exterior surfaces of the enclosure at or just below ambient air temperature. As the distance from the optical path increases (e.g., on the surface of the lower enclosure), the stringency of the temperature requirement is diminished, thereby allowing a greater difference between the surface temperature and the ambient air temperature. This paper presents a comparison of the modeled performance of an active thermal control strategy on the lower enclosure to a passive strategy that employs concrete panels. A life-cycle cost analysis of each option is also presented.

Simulation models of new opto-mechanical systems are often based on engineering experience with older, potentially dissimilar systems. This can result in inaccuracies in the model prediction. A method is needed to gauge the fidelity of new system models in the initial design phases, often in the absence of hardware data. The Nyquist criterion is used to develop a quantitative measure of model fidelity, called the Nyquist fidelity metric. The spatial Nyquist fidelity method is presented which uses the Nyquist fidelity metric to both assess the fidelity of existing complex models and to synthesize new multi-component models starting from architectural considerations such as geometric and material properties of the system. This method also estimates the error bound on the output figures of merit based on the fidelity levels and sensitivity analysis. The Nyquist fidelity method is applied to the Modular Optical Space Telescope (MOST), the Thirty Meter Telescope, and the Stratospheric Observatory for Infrared Astronomy. It is shown in the MOST case study that the Nyquist fidelity method provides a 40% improvement in computational time while assuring less than 5% modal frequency error, and less than 2.2% error in the output figure of merit.

The NRC Herzberg Institute of Astrophysics (NRC-HIA) is currently responsible to contribute Band 3 (84-116 GHz) receivers to the international ALMA project - a partnership involving North America, Europe and, now, Asia. Not only are the technical requirements for these receivers far more stringent than those for any existing radio astronomy receivers operating at these frequencies, but the delivery schedule for these receivers is equally challenging. Since the Asian partnership joined the ALMA project in 2006, NRC-HIA has been asked to deliver an additional 11 cartridges, for a total of 73 units. Some of these new cartridges will be used for the ALMA Compact Array (ACA) and others as spares. Moreover, the project has also requested that these additional cartridges be delivered in the same time period as the original 62 units. To meet this requirement, production must increase from the existing rate of one unit every four weeks to one every two, taxing the existing production infrastructure at NRC-HIA. Additional test facilities and human resources must be planned to sustain the required production rate over the next several years. Industrial involvement is one of the important elements in our production plan. In order to supplement the existing human resources at NRC-HIA, we are planning to outsource a number of low-risk and labor-intensive tasks to industry. However, NRC-HIA will retain overall project management responsibility and will conduct all the cartridge integration and acceptance test activities in-house. This paper focuses on the resource estimation, planning and project management required to deliver the Band 3 receivers to the ALMA project on time and on budget.

Estimates of the cost to construct the Thirty Meter Telescope (TMT) have progressed from rough order parametric analyses at the early Reference Design stage to detailed bottom up estimating at the lowest levels of the TMT Work Breakdown Structure during the Conceptual and Preliminary Design phases. This detailed estimating process is guided by uniform estimating procedures and a contingency estimating methodology that assesses technical, cost and schedule risks for each item that is estimated. Details of the cost estimating techniques, their implementation, uses of the results, and planned next steps will be described.

In the last two years the National Observatory at Tonantzintla Puebla, México (OAN Tonantzintla), has been undergoing several facilities upgrades in order to bring to the observatory suitable conditions to operate as a modern Observational Astronomy Teaching Laboratory. In this paper, we present the management, requirement definition and project advances. We made a quantitative diagnosis about of the functionality of the Tonantzintla Observatory (mainly based in the 1m f/15 telescope) to take aim to educational objectives. Through this project we are taking the steps to correct, to actualize and to optimize the observatory astronomical instrumentation according to modern techniques of observation. We present the design and the first actions in order to get a better and efficient use of the main astronomical instrumentation, as well as, the telescope itself, for the undergraduate, postgraduate levels Observacional Astronomy students and outreach publics programs for elementary school. The project includes the development of software and hardware components based in as a common framework for the project management. The Observatory is located at 150 km away from the headquarters at the Instituto de Astronomía, Universidad Nacional Autónoma de México (IAUNAM), and one of the goals is use this infrastructure for a Remote Observatory System.

This paper describes the FRACTAL Systems & Projects suite. This suite is composed by several tools (GECO, DOCMA and SUMO) that provide the capabilities that all organizations need to store and manage the system information generated along the project's lifetime, from the design phase to the operation phase. The amount of information that is generated in a project keeps growing in size and complexity along the project's lifetime, to an extent that it becomes impossible to manage it without the aid of specific computer-based tools. The suite described in this paper is the solution developed by FRACTAL to assist the execution of different scientific projects, mainly related with telescopes and instruments, for astronomical research centres. These tools help the system and project engineers to maintain the technical control of the systems and to ensure an optimal use of the resources. GECO eases the control of the system configuration data; DOCMA provides the means to organise and manage the documents generated in the project; SUMO allows managing and scheduling the operation, the maintenance activities and the resources during the operational phase of a system. These tools improve the project communication making the information available to the authorized users (project team, customers, Consortium's members, etc). Finally and depending on the project needs, these three tools can be used integrated or in an independent manner.

VST is a survey telescope with a wide field of view (1°x1°). This makes necessary to investigate the image quality over the whole field of view and not just in the centre. The image quality is studied in terms of diameter enclosing the 80% of the PSF energy. Several error sources are analyzed and optical sensitivity analysis are carried out to know the effect of each individual error source on the image quality. The individual contributions are added quadratically in the assumption they are uncorrelated. The worst case is generally found in the border of the field. The average of the results obtained in a number of fields along the whole field of view is considered as a metric for the telescope optical quality. The overall budget is a continuous work in progress because the requirements for the different subsystems, starting from the initial predictions, are then fed back by test data and further analysis.

Large telescopes pose a continuous challenge to systems engineering due to their complexity in terms of requirements, operational modes, long duty lifetime, interfaces and number of components. A multitude of decisions must be taken throughout the life cycle of a new system, and a prime means of coping with complexity and uncertainty is using models as one decision aid. The potential of descriptive models based on the OMG Systems Modeling Language (OMG SysML^TM) is examined in different areas: building a comprehensive model serves as the basis for subsequent activities of soliciting and review for requirements, analysis and design alike. Furthermore a model is an effective communication instrument against misinterpretation pitfalls which are typical of cross disciplinary activities when using natural language only or free-format diagrams. Modeling the essential characteristics of the system, like interfaces, system structure and its behavior, are important system level issues which are addressed. Also shown is how to use a model as an analysis tool to describe the relationships among disturbances, opto-mechanical effects and control decisions and to refine the control use cases. Considerations on the scalability of the model structure and organization, its impact on the development process, the relation to document-centric structures, style and usage guidelines and the required tool chain are presented.

The Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST) provides the critical functions and the environment for the four science instruments on JWST. This complex system development across many international organizations presents unique challenges and unique solutions. Here we describe how the requirement flow has been coordinated through the documentation system, how the tools and processes are used to minimize impact to the development of the affected interfaces, how the system design has matured, how the design review process operates, and how the system implementation is managed through reporting to ensure a truly world class scientific instrument compliment is created as the final product.

The integrated modelling approach is fundamental in telescopes design where it is necessary to merge different disciplines together. This paper describes the integration of optical ray-tracing capabilities within the Matlab computational environment. This approach allows to write automatic procedures to implement a huge number of computations, that are very unpractical to perform in interactive mode by ray tracing software packages. Data produced by computations are stored and automatically analyzed. One of the main benefits from this approach comes from the traceability of the work, that is intrinsically impossible when the optical designer works in interactive mode. The right procedure is built and tuned just the first time and the computation software is available for inspection and check. Furthermore computations and results are easily reproducible simply re-running Matlab scripts. An automatic approach is especially helpful in wide-field telescope projects where the optical quality has to be studied over a wide field of view. This leads to repeat the same computations many times in a number of fields. In interactive mode this would cause a significant waste of optical designer time to repeat many times the same manual procedures. The solution proposed here allows to save time and prevent occasional mistakes.

FAST (Five-hundred-meter Aperture Spherical radio Telescope) focus cabin is driven by 6 cables, moving on a spherical cap of ~ 206 meters in diameter. In order to achieve the required pointing accuracy of the telescope by positioning and orienting the receiver properly, X/Y positioner and Stewart manipulator are employed. In addition, reaction mass dampers (RMD) are investigated to depress the cabin's vibrations at high frequencies. In this paper, a simulation model of FAST focus cabin is created. Control simulation is carried out to evaluate control performance of the focus cabin. As a result of this simulation work, X/Y positioner, Stewart manipulator and reaction mass dampers show satisfied performance in compensating the residual position and orientation errors and depressing vibrations. The simulation work approves the feasibility of this engineering concept, and also paves an efficient approach for optimization in the future design work.

Data avalanche faced in astronomy, astronomical data covers from radio, infrared, optical, X-ray, even gamma ray band. Astronomy enters an all sky-survey era. Transforming data into knowledge depends on data mining techniques. How to effectively and efficiently extract knowledge from databases is an important issue. Especially mining knowledge from different bands or multiband is of great significance. In this paper, we design a system which includes four fundamental blocks: the first is used to create databases; the second for cross-matching objects from different bands, the third for mining knowledge from the large data volume and the last one for final result evaluation. The functionalities of the four blocks are described. The cross-match results are divided, and the analysis mode for each of them is touched upon. Moreover the schemes of classification, regression, clustering analysis and outlier detection are demonstrated.

During operation, astronomical telescope will undergo thermal disturbance, especially more serious in solar telescope, which may cause degradation of image quality. As drives careful thermal load investigation and measure applied to assess its effect on final image quality during design phase. Integrated modeling analysis is boosting the process to find comprehensive optimum design scheme by software simulation. In this paper, we focus on the Finite Element Analysis (FEA) software-ANSYS-for thermal disturbance analysis and the optical design software-ZEMAX-for optical system design. The integrated model based on ANSYS and ZEMAX is briefed in the first from an overview of point. Afterwards, we discuss the establishment of thermal model. Complete power series polynomial with spatial coordinates is introduced to present temperature field analytically. We also borrow linear interpolation technique derived from shape function in finite element theory to interface the thermal model and structural model and further to apply the temperatures onto structural model nodes. Thereby, the thermal loads are transferred with as high fidelity as possible. Data interface and communication between the two softwares are discussed mainly on mirror surfaces and hence on the optical figure representation and transformation. We compare and comment the two different methods, Zernike polynomials and power series expansion, for representing and transforming deformed optical surface to ZEMAX. Additionally, these methods applied to surface with non-circular aperture are discussed. At the end, an optical telescope with parabolic primary mirror of 900 mm in diameter is analyzed to illustrate the above discussion. Finite Element Model with most interested parts of the telescope is generated in ANSYS with necessary structural simplification and equivalence. Thermal analysis is performed and the resulted positions and figures of the optics are to be retrieved and transferred to ZEMAX, and thus final image quality is evaluated with thermal disturbance.

Planned Extremely Large Telescopes will rely on availability of large Deformable Mirror in the 2-3m class. Design and construction of such mirrors are challenging and call for powerful simulation tools. We present an evaluation model which is used to study performance of a large deformable mirror for three actuator topologies. Back sensors topologies are discussed from the point of view of sensor noise propagation. Two methods for estimating the deflection at the actuator locations on the basis of sensor signal are presented and compared regarding the computational power needed.

We have developed physical models of the dispersive optics of several astronomical spectrographs (STIS, CRIRES, X-shooter). The primary goal is to use these models to provide a physically motivated wavelength calibration of these instruments. However, a further advantage of this approach is the possibility to produce detailed simulations of spectroscopic observations as they would appear on the instrumental detectors in 2D. In the case of operational spectrographs, such data can be further processed by the instrument pipeline creating all of the products that would be produced for real data. This enables observers to project existing spectra or theoretical model spectra of their proposed target onto the resolution, sensitivity and format of a given instrument. For instruments in the planning phase, this approach provides a highly accurate method for visualising the capabilities of the proposed instrument under a wide range of possible operating conditions - such as alignment errors, setting angles of gratings, miss-rotation of detector grids to name a few. Mitigation strategies and operational concepts can thus be integrated into the design at a very early stage.

In order to perform detailed dynamic simulation the FEM model must be reduced in order to decrease simulation calculation time while maintaining the essential mechanical characteristics. A mathematical approach has been exploited instead of a "trial and error" procedure, with springs and masses: a more accurate fitting to the FEM model is therefore available. This paper describes the integration of Nastran and Ansys finite element software capabilities within the Matlab - Simulink computational environment.

The VST telescope is a wide field survey telescope partially installed at Cerro Paranal (Chile). Due to the geological nature of the area, telescopes in Chile are always submitted to unpredictable and sometimes severe earthquake conditions. The proper design of an "ad hoc" safety system for the main mirror inside the cell is therefore mandatory for a safe operation of the telescope, in order to avoid unpleasant consequences in terms of critical loss of the main optical element. A multi-step detailed dynamic analysis has been performed in order to asses the characteristic of safety devices, in term of stiffness, damping and positions with respect to the mirror. The paper describes the procedure followed while giving an overview of dynamic analysis capabilities of MSC-Nastran code. The procedure proposed follows the requirements of Eurocode 8 regulations for the design of earthquake safe structures.

We describe the implementation of differential wavefront sampling(DWS) in optical alignment of a pupil-segmented telescope system. As a wavefront-based optical alignment method, DWS can efficiently provide estimations of misalignments present in an optical system by deliberately perturbing optical elements in a systematic manner. This has been demonstrated in our previous numerical studies with realistic uncertainties in wavefront measurements, motion control, and optical surface deformations, suggesting that the method has potential in optical alignment and phasing of pupil-segmented systems such as the future Extremely Large Telescopes (ELTs). The basic idea and procedures of DWS are first described. We then present and discuss preliminary simulations using the currently proposed European Extremely Large Telescope (E-ELT) as an example system.

The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) planet finder instrument for ESO's VLT telescope, scheduled for first light in 2011, aims to detect giant extra-solar planets in the vicinity of bright stars by the aid of an extreme-AO turbulence compensation system and coronagraphic diffraction suppression. Objects found will be characterized through spectroscopic and polarimetric observations. I consider here the effects of micro-obstructions of the beam due to dust and cosmetic defects on the SPHERE image quality.

Image based wavefront sensing methods such as Adaptive Modified Gerchberg-Saxton Phase Retrieval1 (MGS) require a matrix of a-priori phase knowledge to avoid high dynamic range "phase wrapping" during estimation. Previous unwrapping methods have met with limited success or have required some degree of expert intervention. We have succeeded in developing a method and algorithm for automatically unwrapping the phase estimate to generate "prior phase knowledge". By utilizing first-round wavefront sensing results and image processing techniques, the algorithm is able to create sufficient a-priori phase information to feed back to the phase retrieval software. The autonomous phase unwrapping algorithm utilizes edge detection, morphological processing, and spatial filtering, and is able to perform well on a variety of phase wrapping anomalies for both monolithic and segmented optical systems.

The spectral radiance received by a remote sensor is consisted of the self-emitted component directly from the target surface, the reflected component of the solar irradiance at the target surface, and the scattered component by the atmosphere without ever reaching the object surface. The self-emitted radiance from a surface can be calculated by using the temperature and optical characteristics of the surface together with the spectral atmospheric transmittance. The reflected radiance can be calculated by using the BRDF model. MODTRAN4 is used to model the scattered radiance by the atmosphere, and the solar radiation including the direct and diffuse solar energy components. In this paper, the infrared signatures received by a remote sensor are computed by using the spectral transmittances obtained for different sensor positions and for different surface materials.

Telescope-Enclosure-Soil Interaction could result in additional telescope movement due to two main sources: (i) enclosure windshake and (ii) vibrations of machinery located at enclosure, summit and utility facilities. To analyze and minimize these vibrations, a novel FE model was developed based on existing FE models for the TMT enclosure and telescope structures. This integrated structural model adequately represents propagation of vibrations from the source to the telescope structure through surrounding soil/rock region. The model employs 3-D linear-elastic harmonic analysis using commercial FE code ANSYS. Special attention was devoted to adequate modeling of reflecting and non-reflecting boundary conditions. Based on the FE model developed, we examined the effects of soil/rock stiffness and damping upon telescope vibrations and, ultimately, seeing quality. The effects of location, intensity and spectral content of main sources of machinery vibrations were also investigated.

Increasing dimensions of ground based telescopes while implementing Adaptive Optics systems to cancel both structural deformations and atmospheric effects require very large diameters deformable mirrors (DM) and a high number of actuators with large strokes. This has led for the future E-ELT to a 2.5 m diameter DM getting about 8000 actuators. This paper presents a local and a global model of the DM in order to both study its influence function and its dynamical behavior. In the first part, influence function of the mirror is calculated. Results obtained by an analytical way are compared to those obtained numerically. In the second part, modal analysis of the mirror is presented. Results are limited to the first modes. Modal analysis is also only made for the base plate to derive the specific influence of DM's components on the global dynamic behavior. In the last part, optimization methods are used to help designing a 1 m prototype of the DM.