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The Daniel K. Inouye Solar Telescope (DKIST), formerly the Advanced Technology Solar Telescope (ATST), is now in its sixth year of construction. During the two years that have elapsed since our last systems engineering update we have been through factory acceptance of several major subsystems including the enclosure, telescope mount assembly, and the primary mirror. With these major milestones behind us, site assembly in progress, and with the integration, test, and commissioning phase about to begin, we will discuss what has been working well in terms of DKIST systems engineering processes along with some things we could have done better and would do differently if given another chance. The paper examines examples of successes including full-scale factory assembly of major mechanical components and some less optimum outcomes. We explore the reasons for success or failure, including the early delivery and level of detail in factory acceptance test procedures.

The National Solar Observatory’s (NSO) Advanced Technology Solar Telescope (ATST) is the first large U.S. solar telescope accessible to the worldwide solar physics community to be constructed in more than 30 years. The 4-meter diameter facility will operate over a broad wavelength range (0.35 to 28 μm ), employing adaptive optics systems to achieve diffraction limited imaging and resolve features approximately 20 km on the Sun; the key observational parameters (collecting area, spatial resolution, spectral coverage, polarization accuracy, low scattered light) enable resolution of the theoretically-predicted, fine-scale magnetic features and their dynamics which modulate the radiative output of the sun and drive the release of magnetic energy from the Sun’s atmosphere in the form of flares and coronal mass ejections. In 2010, the ATST received a significant fraction of its funding for construction. In the subsequent two years, the project has hired staff and opened an office on Maui. A number of large industrial contracts have been placed throughout the world to complete the detailed designs and begin constructing the major telescope subsystems. These contracts have included the site development, AandE designs, mirrors, polishing, optic support assemblies, telescope mount and coude rotator structures, enclosure, thermal and mechanical systems, and high-level software and controls. In addition, design development work on the instrument suite has undergone significant progress; this has included the completion of preliminary design reviews (PDR) for all five facility instruments. Permitting required for physically starting construction on the mountaintop of Haleakalā, Maui has also progressed. This paper will review the ATST goals and specifications, describe each of the major subsystems under construction, and review the contracts and lessons learned during the contracting and early construction phases. Schedules for site construction, key factory testing of major subsystems, and integration, test and commissioning activities will also be discussed.

The Advanced Technology Solar Telescope (ATST) has recently received National Science Foundation (NSF) approval to begin the construction process. ATST will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. This paper gives an overview of the project, and describes the project management principles and practices that have been developed to optimize both the project's success as well as meeting requirements of the project's funding agency.

The 4m Advance Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading ground-based resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. The project has successfully passed its final design review and the Environmental Impact Study for construction of ATST on Haleakala, Maui, HI has been concluded in December of 2009. The project is now entering its construction phase. As its highest priority science driver ATST shall provide high resolution and high sensitivity observations of the dynamic solar magnetic fields throughout the solar atmosphere, including the corona at infrared wavelengths. With its 4 m aperture, ATST will resolve features at 0."03 at visible wavelengths and obtain 0."1 resolution at the magnetically highly sensitive near infrared wavelengths. A high order adaptive optics system delivers a corrected beam to the initial set of state-of-the-art, facility class instrumentation located in the coude laboratory facility. The initial set of first generation instruments consists of five facility class instruments, including imagers and spectropolarimeters. The high polarimetric sensitivity and accuracy required for measurements of the illusive solar magnetic fields place strong constraints on the polarization analysis and calibration. Development and construction of a fourmeter solar telescope presents many technical challenges, including thermal control of the enclosure, telescope structure and optics and wavefront control. A brief overview of the science goals and observational requirements of the ATST will be given, followed by a summary of the design status of the telescope and its instrumentation, including design status of major subsystems, such as the telescope mount assembly, enclosure, mirror assemblies, and wavefront correction

The temperature of magnetic nanoparticles can be estimated with excellent accuracy using the ratio of the harmonics of the magnetization induced by a harmonic magnetic field. The harmonics can be measured in vivo with high sensitivity. The method has been generalized to measure any physical property influencing the nanoparticle Brownian motion, including temperature, viscosity and bound state. We present theory and preliminary data suggesting that the phase of the harmonics can also be used to estimate the viscosity. The use of the phase should allow more sensitive measurements and alternative ways of separating dynamic from static effects.

The 4m ATST will be the most powerful solar telescope in the world, providing a unique scientific tool to study the Sun and other astronomical objects. The design and development phase for the Advance Technology Solar Telescope (ATST) is progressing. The conceptual design review (CoDR) for the ATST is scheduled for August 2003. We present a brief description of the science requirements of ATST, and remind the reader of some of the technical challenges of building a 4-m solar telescope. We will discuss some of the design strategies that will allow us to achieve the required performance specifications, present conceptual designs for the ATST, and summarize the results of trades we have made on our path to the CoDR. The thermal impacts to local, self-induced seeing with respect to some of our system level trades that have been completed will be discussed.

The Advanced Technology Solar Telescope (ATST) project pl ans to implement thermal control of the primary mirror using jet impingement of temperature controlled air on the back side of the meniscus mirror. This technique will be used to minimize temperature rise of the optical surface due to coating absorption, minimizing mirror seeing effects. The performance of this system has been evaluated using numerical modeling techniques and weather data recorded at the proposed observatory site. To aid in the design of the M1 thermal control system for the ATST, a prototype test bed was designed, fabricated and tested. This paper reviews the progress and results of this development program Keywords: solar telescope, thermal control, mirror seeing 1. INTRODUCTION Telescope image quality is degraded by “seeing” or wavefront error due to non-uniform refractive index of the air within the optical path. In this case, the index variation is due to temperature variations within the convective heat transfer boundary layer adjacent to the optical surface when it is at a different temp erature from the surro unding ambient air. For a solar telescope, this effect, if uncontrolled, can be many orders of magnitude more pronounced than for night time telescopes due to the high level of incident solar radiation. To mitigate seeing, temperature control of all mirrors within the ATST will be required. Thermal contro l of the primary mirror is particularly problematic because the use of a low conductivity glass or glass ceramic meniscus design limits the options for effective control of front surface temperature. Engineering work began by assessing the potential impact of primary mirror seeing. General correlations were developed for seeing based on previous work as well as original analysis in the forced convection regime. Seeing dependence on temperature differences and wind speed over the mirror, or flushing , were then used to estimate seeing based on ‘average’ temperature and wind site characteristics. Th is work helped to both evaluate potential sites as well as provide initial input to image quality based error budgeting. After reviewing a number of potential concepts, the temperature control method selected for the primary mirror was jet impingement cooling on the back surface. This technique provides the high heat transfer coefficient required with moderate air jet velocities. Modeling the performance of such a system was done using a one dimensional heat transfer model subjected to historic temperature and wind conditions r ecorded on the proposed telescope site combined with the seeing correlations developed for the four meter primary mirror. The results are a statistical measure of optical image degradation relative to the error budget allocation. To further mitigate the risk associated with this novel thermal control concept a prototype testing program was developed and implemented. A subscale mirror was used to demonstrate the concept, pin the numerical modeling assumptions, check the optical surface temperature uniformity a nd evaluate edge effects. This information was then used to refine the final system design.

The Advanced Technology Solar Telescope (ATST) has a 4.24m off-axis primary mirror designed to deliver diffraction-limited images of the sun. Its baseline secondary mirror (M2) design uses a 0.65m diameter Silicon Carbide mirror mounted kinematically by a bi-pod flexure mechanism at three equally spaced locations. Unlike other common telescopes, the ATST M2 is to be exposed to a significant solar heat loading. A thermal management system will be developed to accommodate the solar loading and minimize "mirror seeing effect" by controlling the temperature difference between the M2 optical surface and the ambient air at the site. Thermo-elastic analyses for steady state thermal behaviors of the ATST secondary mirror was performed using finite element analysis by I-DEAS TM and PCFRINGE TM for the optical analysis. We examined extensive heat transfer simulation cases and their results are discussed. The goal of this study is to evaluate the optical performances of M2 using thermal models and mechanical models. Thermal responses from the models enable us to manipulate time dependent thermal loadings to synthesize the operational environment for the design and development of TMS.

Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters, stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to adapt to changes in payload mass properties and geometry, through active control of a smart material. MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload geometry and mass properties with modification limited to support structures only. The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally, Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while the active piezoelectric actuator is used for enhanced low frequency isolation. MVIS-II struts are 90% smaller in size and have 91% less mass than previous struts including Honeywell's Vibration Isolation, Suppression, and Steering (VISS). The MVIS-II system is currently integrated in the TacSat-2, which has successfully launched from Wallops Flight Facility on Wallops Island, Virginia in December 2006. MVIS-II was launched under direction of the DoD Space Test Program. This paper will discuss the adaptive design of the MVIS-II isolation system including simulation, testing, and integration. Active and passive strut test results will be presented that demonstrate the wide bandwidth attenuation of vibration disturbances. Simulation results of expected on-orbit performance will also be discussed.

When constructed on the summit of Haleakala on the island of Maui, Hawaii, the Advanced Technology Solar Telescope (ATST) will be the world's largest solar telescope. The ATST is a unique design that utilizes a state-of-the-art off-axis Gregorian optical layout with five reflecting mirrors delivering light to a Nasmyth instrument rotator, and nine reflecting mirrors delivering light to an instrument suite located on a large diameter rotating coude lab. The design of the telescope mount structure, which supports and positions the mirrors and scientific instruments, has presented noteworthy challenges to the ATST engineering staff. Several novel design solutions, as well as adaptations of existing telescope technologies to the ATST application, are presented in this paper. Also shown are plans for the control system and drives of the structure.

The Advanced Technology Solar Telescope (ATST) will be the most powerful solar telescope and the world's leading resource for studying solar magnetism that controls the solar wind, flares, coronal mass ejections and variability in the Sun's output. Development of this four-meter off-axis solar telescope has presented many optical design challenges including: • support of both Nasmyth and flexible coude lab instrumentation, • incorporation of an integrated adaptive optics system, • thermal control of optics, and • optical alignment of multiple off-axis conics. This paper gives an overview of the optical design, error budgeting, and the performance modeling done to ensure the telescope will satisfy its optical performance requirements.

Photobleaching causes progressive fading in successive slices of a through-focus series, so that the last image taken in the series can have a significantly lower signal-to-noise ratio than the first. Bleaching is oftensuccessfully minimized by including antifade additives in the specimen preparation and/or by reducing theoptical dose to the specimen. However, these measures may not be sufficient in a through-focus series where many slices must be taken. This paper presents a simple approach to ameliorating the effects of bleaching, which is to progressively increase the integration times so as to maintain constant signal level from slice to slice. I refer to the sequence of integration times as an integration schedule. I develop the equations for integration scheduling from the physical assumptions and discuss how the method affects image quality.Keywords: microscopy, fluorescence, photobleaching, confocal, three-dimensional microscopy, photodetector 1. INTRODUCTION In fluorescence microscopy, a structure or function of interest in a specimen is labeled with a fluorescent probe.

A new algorithm is presented which uses maximum likelihood (ML) estimation and convex constraints to restore edge information in a robust and accurate way for microscope images. The convex constraints are spatially variant bounds on the image intensities and the directions of gradients, and they are extracted from an image restored with strong smoothing constraints. The high resolution estimate is obtained by maximizing the ML objective under the convex constraints and relaxed smoothing, using conjugate gradient and constrained optimization techniques. Relaxed smoothing allows edges in the final estimate, while the bound constraints preserve the robustness of the estimate. The convex constraints can be considered as a generalization of the positivity constraint which has been widely used in image restoration. The method does not impose any constraints on the profile of the edges, and it compares favorably with first order Bayesian methods which are frequently used for edge enhanced restoration in medical imaging. The performance of the method is demonstrated by restoring an image obtained from a confocal microscope.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

When a confocal fluorescence microscope with a high numerical aperture oil immersion objective is focused deep into an aqueous medium, aberrations result which weaken and blur the observed image. We have designed, fabricated and tested a two-level binary phase mask which partially corrects these aberrations, improving image brightness and resolution. A four- level mask was also designed, fabricated and tested with further brightness and resolution improvement. The mask designs and simulated and measured results are presented in this paper.

Even in confocal scanning, longitudinal resolution is poorer than lateral resolution. It is therefore of interest to go `beyond confocal' and achieve still better optical sectioning by image restoration methods. In our previous work we applied two methods to simulated 3D microscope images: the constrained Jansson-van Cittert (JVC) method, which is a deterministic regularized image restoration algorithm, and the expectation-maximization (EM) algorithm, which is a method to obtain the maximum likelihood solution of the restoration problem under Poisson image statistics. In this paper we apply both the JVC algorithm and the EM algorithm to real image data obtained from our laser scanning confocal microscope. Slices of the original and restored images agree with our earlier numerical simulations. Specifically: (a) optical sectioning is improved by both algorithms; (b) the JVC restoration is noisier than the image restored with the EM algorithm, showing the advantage of the ML approach under low light conditions; (c) noise in the EM restoration shows that regularization is still needed.

A major limiting factor in polarization microscopy is the rotation of the plane of polarization at oblique interfaces in the optical train, which leads to severe degradation of image quality. Polarization aberration theory has provided an effective framework for studying two- dimensional image formation and optical restoration in these systems. Here we extend the polarization aberration model to three dimensions. A model system is chosen in which polarization aberrations are optically corrected and image quality restored. Closed-form expressions for the aberrated and restored 3-D space-variant point spread functions are derived, and the contributions of the various kinds of polarization aberrations are described.

The anatomic and functional localization of brain lesions for neurologic diagnosis and brain surgery is facilitated by labeling the cortical surface in 3D images. This paper presents a method which extracts cortical contours from magnetic resonance (MR) image series and then produces a planar surface map which preserves important anatomic features. The resultant map may be used for manual anatomic localization as well as for further automatic labeling. Outer contours are determined on MR cross-sectional images by following the clear boundaries between gray matter and cerebral-spinal fluid, skipping over sulci. Carrying this contour below the surface by shrinking it along its normal produces an inner contour that alternately intercepts gray matter (sulci) and white matter along its length. This procedure is applied to every section in the set, and the image (grayscale) values along the inner contours are radially projected and interpolated onto a semi-cylindrical surface with axis normal to the slices and large enough to cover the whole brain. A planar map of the cortical surface results by flattening this cylindrical surface. The projection from inner contour to cylindrical surface is unique in the sense that different points on the inner contour correspond to different points on the cylindrical surface. As the outer contours are readily obtained by automatic segmentation, cortical maps can be made directly from an MR series.

A long-standing problem in polarized light microscopy has been the inability, due to polarization aberrations, to achieve simultaneously high spatial resolution and high contrast. The rotation of the plane of polarization at oblique interfaces between crossed polars causes the pupil function to resemble a dark cross rather than being uniformly dark. Likewise, the point spread function has the visual appearance of a four-leaf clover rather than the ideal Airy disk, and is also space-variant. Images formed with these systems are severely degraded. In this paper the theory of polarization aberrations is applied to the analysis of three solutions to this problem: Reducing the system aperture to block troublesome high-aperture rays; the AVEC-POL method, in which high bias compensation introduces counterbalancing aberrations; and the polarization rectifier, an optical element designed to introduce equal and opposite rotations of the electric vector.

We report on the development of a laser scanning fluorescence microscope possessing several features which facilitate its application to biological and biophysical analyses in living cells. It is built around a standard inverted microscope stand, enabling the use of standard optics, micromanipulation apparatus, and conventional (including video) microscopy in conjunction with laser scanning. The beam is scanned across the specimen by a pair of galvanometer-mounted mirrors, driven by a programmable controller which can operate in three modes: full raster scan, region of interest, and random-access. A full 512x512 pixel image can be acquired in one second. In region of interest mode, several subareas of the field can be selected for more rapid or detailed analysis. For those cases where the time scale of the observed phenomenon precludes full-field imaging, or where a full-field image is unnecessary, the random access mode enables an arbitrary pattern of isolated points to be selected and rapidly sequenced through. Via a graphical user interface implemented on the system's host computer, a user will be able to take a scout image either with video or a full-field laser scan, select regions or points on the scout image with a mouse, and set up experimental parameters such as detector integration times with a window-style menu. The instrument is designed to be a flexible testbed for investigating new techniques, without compromising its utility as a tool for biological research.