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We provide an update on the construction status of the Daniel K. Inouye Solar Telescope. This 4-m diameter facility is designed to enable detection and spatial/temporal resolution of the predicted, fundamental astrophysical processes driving solar magnetism at their intrinsic scales throughout the solar atmosphere. These data will drive key research on solar magnetism and its influence on solar winds, flares, coronal mass ejections and solar irradiance variability. The facility is developed to support a broad wavelength range (0.35 to 28 microns) and will employ state-of-the-art adaptive optics systems to provide diffraction limited imaging, resolving features approximately 20 km on the Sun. At the start of operations, there will be five instruments initially deployed: Visible Broadband Imager (VBI; National Solar Observatory), Visible SpectroPolarimeter (ViSP; NCAR High Altitude Observatory), Visible Tunable Filter (VTF (a Fabry-Perot tunable spectropolarimeter); Kiepenheuer Institute for Solarphysics), Diffraction Limited NIR Spectropolarimeter (DL-NIRSP; University of Hawaii, Institute for Astronomy) and the Cryogenic NIR Spectropolarimeter (Cryo-NIRSP; University of Hawaii, Institute for Astronomy). As of mid-2016, the project construction is in its 4th year of site construction and 7th year overall. Major milestones in the off-site development include the conclusion of the polishing of the M1 mirror by University of Arizona, College of Optical Sciences, the delivery of the Top End Optical Assembly (L3), the acceptance of the Deformable Mirror System (Xinetics); all optical systems have been contracted and are either accepted or in fabrication. The Enclosure and Telescope Mount Assembly passed through their factory acceptance in 2014 and 2015, respectively. The enclosure site construction is currently concluding while the Telescope Mount Assembly site erection is underway. The facility buildings (Utility and Support and Operations) have been completed with ongoing work on the thermal systems to support the challenging imaging requirements needed for the solar research. Finally, we present the construction phase performance (schedule, budget) with projections for the start of early operations.

The Daniel K. Inouye Solar Telescope (DKIST) is a 4-meter solar observatory under construction at Haleakala, Hawaii [1]. The Visible Broadband Imager (VBI) is a first light instrument that will record images at the highest possible spatial and temporal resolution of the DKIST at a number of scientifically important wavelengths [2]. The VBI is a pathfinder for DKIST instrumentation and a test bed for developing processes and procedures in the areas of unit, systems integration, and user acceptance testing. These test procedures have been developed and repeatedly executed during VBI construction in the lab as part of a "test early and test often" philosophy aimed at identifying and resolving issues early thus saving cost during integration test and commissioning on summit. The VBI team recently completed a bottom up end-to-end system test of the instrument in the lab that allowed the instrument’s functionality, performance, and usability to be validated against documented system requirements. The bottom up testing approach includes four levels of testing, each introducing another layer in the control hierarchy that is tested before moving to the next level. First the instrument mechanisms are tested for positioning accuracy and repeatability using a laboratory position-sensing detector (PSD). Second the real-time motion controls are used to drive the mechanisms to verify speed and timing synchronization requirements are being met. Next the high-level software is introduced and the instrument is driven through a series of end-to-end tests that exercise the mechanisms, cameras, and simulated data processing. Finally, user acceptance testing is performed on operational and engineering use cases through the use of the instrument engineering graphical user interface (GUI). In this paper we present the VBI bottom up test plan, procedures, example test cases and tools used, as well as results from test execution in the laboratory. We will also discuss the benefits realized through completion of this testing, and share lessons learned from the bottoms up testing process.

We are developing a high sensitivity and fast readout near-infrared (NIR) detector and an integral field unit (IFU) for making spectro-polarimetric observations of rapidly varying chromospheric spectrum lines, such as He I 1083 nm and Ca II 854 nm, in the next space-based solar mission SOLAR-C. We made tests of a 1.7 μm cutoff H2RG detector with the SIDECAR ASIC for the application in SOLAR-C. It’s important to verify its perfor- mance in the temperature condition around -100 °C, which is hotter than the typical temperature environment used for a NIR detector. We built a system for testing the detector between -70 °C and -140 °C. We verified linearity, read-out noise, and dark current in both the slow and fast readout modes. We found the detector has to be cooled down lower than -100 °C because of significant increase of the number of hot pixels in the hotter environment. The compact and polarization maintenance IFU was designed using fiber-optic ribbons consisting of rectangular cores which exhibit good polarization maintenance. A Silicone adhesive DC-SE9187L was used to hold the fragile fiber-optic ribbons in a metal housing. Polarization maintenance property was confirmed though polarization calibration as well as temperature control are required to suppress polarization crosstalk and to achieve the polarization accuracy in SOLAR-C.

ASO-S is a mission proposed for the 25th solar maximum by the Chinese solar community. The scientific objectives are to study the relationships among solar magnetic field, solar flares, and coronal mass ejections (CMEs). ASO-S consists of three payloads: Full-disk Magnetograph (FMG), Lyman-alpha Solar Telescope (LST), and Hard X-ray Imager (HXI), to measure solar magnetic field, to observe CMEs and solar flares, respectively. ASO-S is now under the phase-B studies. This paper makes a brief introduction to the mission. © 2015 SPIE.

In this paper we present Big Bear Solar Observatory’s (BBSO) newest adaptive optics system – AO-308. AO-308 is a result of collaboration between BBSO and National Solar Observatory (NSO). AO-308 uses a 357 actuators deformable mirror (DM) from Xinetics and its wave front sensor (WFS) has 308 sub-apertures. The WFS uses a Phantom V7.3 camera which runs at 2000 Hz with the region of interest of 416×400 pixels. AO-308 utilizes digital signal processors (DSPs) for image processing. AO-308 has been successfully used during the 2013 observing season. The system can correct up to 310 modes providing diffraction limited images at all wavelengths of interest.

Chinese Giant Solar Telescope (CGST) is the next generation ground-based solar telescope which was formally listed into the National Plans of Major Science and Technology Infrastructures. We have got series progresses of CGST in the recent years, from site testing to detailed designs. CGST is currently designed to be an 8m Ring Solar Telescope (RST). As an 8-meter solar telescope, the designing of CGST still faces some serious problems, although the ring structure is propitious to the thermo controlling and the high precision magnetic field measuring. The active control and the optical system of CGST are introduced. Then, simulations and the key calculations of the telescope, including the polarization analysis and the thermo calculation result are displayed. The present site testing methods and some results are introduced too. Finally, as the comparison in science and technology, the Chinese space solar telescope plans, such as the Deep Space Solar Observatory (DSO) and its progress are simply introduced.

We report on the multi-conjugate adaptive optics (MCAO) system of the New Solar Telescope (NST) at Big Bear Solar Observatory which has been integrated in October 2013 and is now available for MCAO experiments. The NST MCAO system features three deformable mirrors (DM), and it is purposely flexible in order to offer a valuable facility for development of solar MCAO. Two of the deformable mirrors are dedicated to compensation of field dependent aberrations due to high-altitude turbulence, whereas the other deformable mirror compensates field independent aberrations in a pupil image. The opto-mechanical design allows for changing the conjugate plane of the two high-altitude DMs independently between two and nine kilometers. The pupil plane DM can be placed either in a pupil image upstream of the high-altitude DMs or downstream. This capability allows for performing experimental studies on the impact of the geometrical order of the deformable mirrors and the conjugate position. The control system is flexible, too, which allows for real-world analysis of various control approaches. This paper gives an overview of the NST MCAO system and reveals the first MCAO corrected image taken at Big Bear Solar Observatory.

A multi-conjugate adaptive optics (MCAO) system is being built for the world's largest aperture 1.6m solar telescope, New Solar Telescope, at the Big Bear Solar Observatory (BBSO). The BBSO MCAO system employs three deformable mirrors to enlarge the corrected field of view. In order to characterize the MCAO performance with different optical configurations and DM conjugated altitudes, the BBSO MCAO setup also needs to be flexible. In this paper, we present the optical design of the BBSO MCAO system.

The Massively Multiplexed Spectrograph (mxSPEC) is a new instrument concept that takes advantage of modern high-speed large-format focal plane arrays (FPAs) and high efficiency bandpass isolation filters to multiplex spectra from many slices of the telescope field simultaneously onto the FPAs within a single grating spectrograph. This design greatly reduces the time required to scan a large telescope field, and with current technologies can achieve more than a factor of 50 or more improvement of the system efficiency over a conventional long-slit spectrograph. Furthermore, several spectral lines can be observed at the same time with proper selection of the diffraction grating, further improving the efficiency of this design to more than two orders of magnitude over conventional single-slit, single-wavelength instrument. This paper describes an experimental, proof-of-concept, 40-slit full-disk spectrograph that demonstrates the feasibility of this new instrument concept and its potential for solar physics research including helioseismology, dynamic solar events, and global scale magnetic field observation of the solar disk and the corona. We also present the preliminary design of a 4-line, 55-slit spectroheliograph that can serve as the template for the instruments of the next generation synoptic solar observatory.

The Visible Broadband Imager (VBI) is one of several first-light instruments of the Daniel K. Inouye Solar Telescope (DKIST, formerly known as the Advanced Technology Solar Telescope (ATST)). Operating at discrete wavelengths within a range of 390-860 nm, the VBI will be capable of sampling the solar atmosphere in several layers at the diffraction limit of DKIST’s 4 meter aperture. The layers are selected by the peak wavelength and bandpass width of its interference filters that have to be manufactured to very tight specifications. We present the results of testing performed at the National Solar Observatory’s Dunn Solar Telescope (DST) to confirm that the requirements were met by the vendor.

The SpectroPolarimetric Imager for the Energetic Sun (SPIES) is a project to develop a new class of spectropolarimetric instrument for the study of highly dynamic solar phenomena. Understanding the physics of dynamic solar phenomena requires detailed information about the magnetic, thermal, and dynamic properties of the solar atmosphere at every stage of their evolution. Although these properties can be obtained with existing highperformance spectropolarimeters such as the SpectroPolarimeter onboard the Hinode space solar observatory or the Facility IR Spectropolarimeter of the Dunn Solar Telescope, these instruments cannot observe the required field of view with temporal resolution that can resolve the dynamic timescale of these energetic events. SPIES-2K is an experimental true-imaging spectropolarimeter developed under this program to address this deficiency in our observing capability. It is based on a fiber-optic integral field unit containing 2,048 standard multimode fused silica fibers, and is capable of observing a 64 x 32 pixels field simultaneously with high spatial and spectral resolution. Moreover, it can obtain the full Stokes spectra of the field with a maximum temporal resolution of a few seconds. This paper presents the design and characteristics of the instrument, as well as preliminary results obtained at Fe I 1565 nm wavelength. Additionally, this paper also reports on recent studies of the polarization maintenance optical fiber ribbon constructed from rectangular element fibers for the Birefringence Fiber-Optic Image Slicer, and discusses its application to future generation of SPIES and other astronomical spectropolarimetry projects.

The Advanced Technology Solar Telescope (ATST) is a 4-meter solar observatory under construction at Haleakala, Hawaii. The simultaneous use of multiple instruments is one of the unique capabilities that makes the ATST a premier ground based solar observatory. Control of the instrument suite is accomplished by the Instrument Control System (ICS), a layer of software between the Observatory Control System (OCS) and the instruments. The ICS presents a single narrow interface to the OCS and provides a standard interface for the instruments to be controlled. It is built upon the ATST Common Services Framework (CSF), an infrastructure for the implementation of a distributed control system. The ICS responds to OCS commands and events, coordinating and distributing them to the various instruments while monitoring their progress and reporting the status back to the OCS. The ICS requires no specific knowledge about the instruments. All information about the instruments used in an experiment is passed by the OCS to the ICS, which extracts and forwards the parameters to the appropriate instrument controllers. The instruments participating in an experiment define the active instrument set. A subset of those instruments must complete their observing activities in order for the experiment to be considered complete and are referred to as the must-complete instrument set. In addition, instruments may participate in eavesdrop mode, outside of the control of the ICS. All instrument controllers use the same standard narrow interface, which allows new instruments to be added without having to modify the interface or any existing instrument controllers.

L-3 Integrated Optical Systems (IOS) Division has been selected by the National Solar Observatory (NSO) to design and produce the Top End Optical Assembly (TEOA) for the 4-meter Advanced Technology Solar Telescope (ATST) to operate at Haleakalā, Maui. ATST will perform to a very high optical performance level in a difficult thermal environment. The TEOA, containing the 0.65-meter silicon carbide secondary mirror and support, mirror thermal management system, mirror positioning and fast tip-tilt system, field stop with thermally managed heat dump, thermally managed Lyot stop, safety interlock and control system, and support frame, operates in the "hot spot" at the prime focus of the ATST and so presents special challenges. In this paper, we describe progress in the L-3 technical approach to meeting these challenges, including silicon carbide off-axis mirror design, fabrication, and high accuracy figuring and polishing all within L-3; mirror support design; the design for stray light control; subsystems for opto-mechanical positioning and high accuracy absolute mirror orientation sensing; Lyot stop design; and thermal management of all design elements to remain close to ambient temperature despite the imposed solar irradiance load.

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 Coronal Solar Magnetism Observatory (COSMO) is a facility dedicated to measuring magnetic fields in the corona and chromosphere of the Sun. It will be located on a mountaintop in the Hawaiian Islands and will replace the current Mauna Loa Solar Observatory (MLSO). COSMO will employ a suite of instruments to determine the magnetic field and plasma conditions in the solar atmosphere and will enhance the value of data collected by other observatories on the ground (SOLIS, ATST, FASR) and in space (SDO, Hinode, SOHO, GOES, STEREO, DSCOVR, Solar Probe+, Solar Orbiter). The dynamics and energy flow in the corona are dominated by magnetic fields. To understand the formation of Coronal Mass Ejections (CMEs), their relation to other forms of solar activity, and their progression out into the solar wind requires measurements of coronal magnetic fields. The COSMO suite includes the Large Coronagraph (LC), the Chromosphere and Prominence Magnetometer (ChroMag) and the K-Coronagraph. The Large Coronagraph will employ a 1.5 meter fuse silica singlet lens and birefringent filters to measure magnetic fields out to two solar radii. It will observe over a wide range of wavelengths from 500 to 1100 nm providing the capability of observing a number of coronal, chromospheric, and photospheric emission lines. Of particular importance to measuring coronal magnetic fields are the forbidden emission lines of Fe XIII at 1074.7 nm and 1079.8 nm. These lines are faint and require the very large aperture. NCAR and NSF have provided funding to bring the COSMO Large Coronagraph to a preliminary design review (PDR) state by the end of 2013.

A low-order solar adaptive optics (AO) system, which consists of a fine tracking loop with a tip/tilt mirror and a correlation tracker, and a high-order correction loop with a 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor and a high-order wavefront correction controller, had been successfully developed and installed at 1-m New Vacuum Solar Telescope of Full-shine Lake (also called Fuxian Lake) Solar Observatory. This system is an update of the 37-element solar AO system designed for the 26-cm Solar Fine Structure Telescope at Yunnan Astronomical Observatory in 2009. The arrangement of subapertures of the Shack-Hartmann wavefront sensor was changed from square to hexagon to achieve better compensation performance. Moreover, the imaging channel of the updated system was designed to observe the Sun at 710nm and 1555nm simultaneously. The AO system was integrated into the solar telescope in 2011, and AO-corrected high resolution sunspots and granulation images were obtained. The observational results show that the contrast and resolution of the solar images are improved evidently after the correction by the AO system.

Mankind has been eager to know the variation of the atmospheric change processes in which the sun play a most important role, So research the Sun activity is a hot point. Observe and analyze its ultraviolet(UV) spectra is a valid way to know the Sun activity, solar UV radiation flux and upper atmospheric absorption of UV is representative of the sun activity. The solar UV emission lines are generally optically thin, so the detection aroused great attention. This paper provide an overview of the past two decades advances instrumentation for solar UV observation. Emphasis is given to the great mission such as OSO 8(Orbiting Solar Observatory 8), SOHO(Solar and Heliospheric Observatory), TRACE(Transition Region and Coronal Explorer), SDO(Solar Dynamics Observatory) and KuaFu, especially to their UV instrumentation and scientific objective, some outlook is proposed.

The discrepancy in annual changes of Earth albedo anomaly among the Had3CM prediction, ground and low Earth orbit measurements attracts great academic attention world-wide. As a part of our on-going study for better understanding of such discrepancy, we report a new earthshine measurement simulation technique. It combines the light source (the Sun), targets (the Earth and the Moon) and a hypothetical detector in a real scale Integrated Monte-Carlo Ray Tracing (IRT) computation environment. The Sun is expressed as a Lambertian scattering sphere, emitting 1.626x10 26 W over 400nm- 750nm in wavelength range. Whilst we are in the process of developing a complex Earth model consisting of land, sea and atmosphere with appropriate BRDF models, a simplified Lambertian Earth surface with 0.3 in uniform albedo was used in this study. For the moon surface, Hapke's BRDF model is used with double Henry-Green phase function. These elements were then imported into the IRT computation of radiative transfer between their surfaces. First, the irradiance levels of earthshine and moonshine lights were computed and then confirmed that they agree well with the measurement data from Big Bear Solar Observatory. They were subsequently used in determination of the Earth bond albedo of about 0.3 that is almost identical to the input Earth albedo of 0.3. These computations prove that, for the first time, the real scale IRT model was successfully deployed for the Earthshine measurement simulation and, therefore, it can be applicable for other ground and space based measurement simulation of reflected lights from the Earth and the Moon.

The 1.6-meter New Solar Telescope (NST) is currently the world's largest aperture solar telescope. The NST is newly built at Big Bear Solar Observatory (BBSO). Among other instruments, the NST is equipped with several focal plane instruments operating in the near infrared (NIR). In order to satisfy the diverse observational requirements of these scientific instruments, a 1024 × 1024 HgCdTe TCM8600 CMOS camera manufactured by Rockwell Scientific Company has been repackaged and upgraded at Infrared Laboratories Inc. A new ND-5 dewar was designed to house the TCM8600 array with a low background filter wheel, inverted operation and at least 12 hours of hold time between fills. The repackaged camera will be used for high-resolution NIR photometry at the NST Nasmyth focus on the telescope and high-precision NIR spectro-polarimetry in the NST Coud´e Lab below. In March 2010, this repackaged camera was characterized in the Coud´e Lab at BBSO. This paper presents the design of new dewar, the detailed process of repackaging and characterizing the camera, and a series of test results.

The Multi-Application Solar Telescope (MAST) is a 50 cm diameter class telescope to be installed by AMOS on the Udaipur Solar Observatory's Island on the Lake Fatehsagar in India. Despite its limited size, the telescope is expected to be competitive with respect to worldwide large and costly projects thanks to its versatility regarding science goals and due to its demanding optomechanical and thermal specification. This paper describes the latest, on-going and forthcoming activities, including factory assembly, integration and testing, followed by on-site installation and commissioning activities. Emphasis is put on the highly demanding thermal control of the telescope, showing development and results for the specific techniques employed on this purpose. Other key features also depicted are the unusual tracking and alignment control solutions on such a specific science target like the Sun.

The largest solar telescope, the 1.6-m New Solar Telescope (NST) has been installed and is being commissioned at Big Bear Solar Observatory (BBSO). It has an off-axis Gregorian configuration with a focal ratio of F/52. Early in 2009, first light scientific observations were successfully made at the Nasmyth focus, which is located on the east side of the telescope structure. As the first available scientific instruments for routine observation, Nasmyth focus instrumentation (NFI) consists of several filtergraphs offering high spatial resolution photometry in G-band 430 nm, Ha 656 nm, TiO 706 nm, and covering the near infrared 1083 nm, 1.6 μm, and 2.2 μm. With the assistance of a local correlation tracker system, diffraction limited images were obtained frequently over a field-of-view of 70 by 70 after processed using a post-facto speckle reconstruction algorithm. These data sets not only serve for scientific analysis with an unprecedented spatial resolution, but also provide engineering feedback to the NST operation, maintenance and optimization. This paper reports on the design and the implementation of NFI in detail. First light scientific observations are presented and discussed.

The Common Services Framework (CSF) is a software architecture developed at the National Solar Observatory for control of the Advanced Technology Solar Telescope (ATST). The framework was designed with the intent to make it independent of the ATST application and freely available to other projects. As part of the System Design phase for the Telescope Control System upgrade and Next Generation Adaptive Optics projects at the W. M. Keck Observatory a number of software frameworks and middleware were evaluated. Of those evaluated, CSF was selected as one of the primary choices for all or part of the software architecture and will be pursued further in the next design phases. This paper discusses the evaluation of CSF at Keck and some possible evolutions of the framework.

New Jersey Institute of Technology, in collaboration with the University of Hawaii and the Korea Astronomy & Space Science Institute, has successfully developed and installed a 1.6 m clear aperture, off-axis New Solar Telescope (NST) at the Big Bear Solar Observatory. The NST will be the largest aperture solar telescope in the world until the 4 m Advanced Technology Solar Telescope (ATST) and 4 m European Solar Telescope (EST) begin operation in the next decade. Meanwhile, the NST will be the largest off-axis telescope before the 8.4 m segmented Giant Magellan Telescope (GMT) comes on-line. The NST is configured as an off-axis Gregorian system consisting of a parabolic primary, prime focus field stop and heat reflector, elliptical secondary and diagonal flats. The primary mirror is made of Zerodur from Schott and figured to a final residual error of 16 nm rms by Steward Observatory Mirror Lab. The final focal ratio is f/52. The 180 circular opening in the field stop defines the maximal square field-of-view. The working wavelength range will cover 0.4 to 1.7 μm in the Coud´e Lab two floors beneath the telescope, and all wavelengths including far infrared at the Nasmyth focus on an optical bench attached to the side of the telescope structure. First-light scientific observations have been attained at the Nasmyth focus and in the Coud´e Lab. This paper presents a detailed description of installation and alignment of the NST. First-light observational results are also shown to demonstrate the validity of the NST optical alignment.

We present a low cost adaptive optics system developed for the solar observatory at Istituto Ricerche Solari Locarno (IRSOL), Switzerland. The Shack-Hartmann Wavefront Sensor is based on a Dalsa CCD camera with 256 pixels × 256 pixels working at 1kHz. The wavefront compensation is obtained by a deformable mirror with 37 actuators and a Tip-Tilt mirror. A real time control software has been developed on a RTAI-Linux PC. Scicos/Scilab based software has been realized for an online analysis of the system behavior. The software is completely open source.

We present our recent process on a portable solar adaptive Optics system, which is aimed for diffraction-limited imaging in the 1.0 ~ 5.0-μm infrared wavelength range with any solar telescope with an aperture size up to 1.6 meters. The realtime wave-front sensing, image processing and computation are based on a commercial multi-core personal computer. The software is developed in LabVIEW. Combining the power of multi-core imaging processing and LabVIEW parallel programming, we show that our solar adaptive optics can achieve excellent performance that is competitive with other systems. In addition, the LabVIEW's block diagram based programming is especially suitable for rapid development of a prototype system, which makes a low-cost and high-performance system possible. Our adaptive optics system is flexible; it can work with any telescope with or without central obstruction with any aperture size in the range of 0.6~1.6 meters. In addition, the whole system is compact and can be brought to a solar observatory to perform associated scientific observations. According to our knowledge, this is the first adaptive optics that adopts the LabVIEW high-level programming language with a multi-core commercial personal computer, and includes the unique features discussed above.

The area of high precision solar spectropolarimetry has made great advances in recent years and the Zurich IMaging POLarimeter (ZIMPOL) systems have played a major role in that. ZIMPOL reaches a polarimetric accuracy of 10-5 by using fast (kHz) polarization modulation/demodulation of the light beam in combination with large-area array detectors. A new generation of improved cameras (ZIMPOL-3) are being implemented for the scientific observations at the solar observatory at Istituto Ricerche Solari Locarno. The new system is based on a flexible and compact modular design, which easily adapts to new applications. A faster electronics and new sensors with higher quantum efficency compared to the previous ZIMPOL versions, allow to achieve a better overall efficency. Future plans include observing campaigns at foremost large telescopes and the exploration of new technologies (e.g. CMOS).

The design of the 4 telescopes that make up the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDOAIA) is described. This includes the optical design, optical mounting system, front aperture filters, and launch protection system. SDO-AIA is a study of taking a difficult telescope design and making four of them. We describe the technical challenges associated with the telescope mounting, mirror mounting, and the front aperture filter design and launch protection.

We have developed a state-of-the-art image slicer Integral Field Unit (IFU) for the McMath-Pierce Solar Telescope (McMP) located at Kitt Peak National Solar Observatory. The IFU will be used for high-resolution 3-dimensional spectroscopy and polarimetry over a small field of view that is well corrected by adaptive optics. It consists of 19 effective slices that correspond to a field of view of 6.27"x 7". The IFU delivers a 152" long slit to an existing spectrograph producing diffraction-limited 3-dimensional spectroscopy. The 3-D instrument is being used for highspatial and high-temporal resolution imaging of the Sun, which is crucial for the magnetic field and spectroscopic studies of 2-dimensional solar fine structures. We discuss the instrument construction, laboratory test and on-site trial observations with the McMP.

The New Solar Telescope (NST) is an off-axis Gregorian telescope at Big Bear Solar Observatory (BBSO). This paper presents the expected aberrations due to misalignments of the secondary mirror for a general Gregorian telescope using an optical model of the on-axis "parent" telescope version of NST. The sensitivities of linear astigmatism and constant coma found by perturbing the axisymmetric model are presented and shown to match those predicted by the theory. Then we discuss how the actual aberrations are different due to the off-axis nature of the NST. Finally, we discuss the effect of the misalignments on the pointing of the telescope.

High-altitude profiles of the parameters of atmospheric air currents in the lower surface layer were measured with the use of a meteorological mast of 32 m in height. A mobile ultrasonic meteosystem was used for the measurements. The theory of similarity for turbulence in anisotropic boundary layer has been verified. The measured vertical profiles of main turbulence parameters have an oscillating character. High-altitude profiles of vertical outer scale are given, reconstructed from measurements by two independent techniques. An equation for the outer turbulence scale is given, determined by the departure from the 2/3-law in the structure temperature function. This scale depends on temperature dispersion and structural characteristic of temperature fluctuations. A satisfactory agreement between values of such outer scale and those of the Tatarskii outer scale is observed.

We are constructing a spectro-­polarimeter using the 40-­cm coronagraph at the Evans Solar Facility of the National Solar Observatory in Sunspot, NM for the purpose of measuring the vector magnetic field in prominences and filaments. The Prominence Magnetometer (ProMag) is comprised of a polarization modulation package and a spectrograph. The modulation optics are located at the prime focus of the coronagraph along with calibration optics and a beamsplitter that creates two beams of orthogonal Stokes states. The spectrograph resides at the coude focus of the coronagraph. The polarizations of the two chromospheric lines of neutral helium, at 587.6 nm and 1083.0 nm, are to be observed simultaneously. We present details of the design of the spectro-­polarimeter.

Understanding the Sun's magnetic field related activity is far from complete as reflected in the limited ability to make accurate predictions of solar variability. To advance our understanding of solar magnetism, the National Solar Observatory (NSO) constructed the Synoptic Optical Long-term Investigations of the Sun (SOLIS) suite of instruments to conduct high precision optical measurements of processes on the Sun whose study requires sustained observations over long time periods. The Vector Spectromagnetograph (VSM), the principal SOLIS instrument, has been in operation since 2003 and obtains photospheric vector data, as well as photospheric and chromospheric longitudinal magnetic field measurements. Instrument performance is being enhanced by employing new, high-speed cameras that virtually freeze seeing, thus improving sensitivity to measure the solar magnetic field configuration. A major operational goal is to provide real-time and near-real-time data for forecasting space weather and increase scientific yield from shorter duration solar space missions and ground-based research projects. The National Solar Observatory proposes to build two near-duplicates of the VSM instrument and place them at international sites to form a three-site global VSM network. Current electronic industry practice of short lifetime cycles leads to improved performance and reduced acquisition costs but also to redesign costs and engineering impacts that must be minimized. The current VSM instrument status and experience gained from working on the original instrument is presented herein and used to demonstrate that one can dramatically reduce the estimated cost and fabrication time required to duplicate and commission two additional instruments.

This work presents the results of measurements of intradome astroclimate parameters of the AZT-14 telescope of Sayan solar observatory of the ISTP SB. The picture of airflows concerned with the warm air run-out though leaky connections and air mixing inside the telescope after dome opening is obtained. It is shown that the value of the structure characteristic of the refractive index Cn2 in closed and open dome can 1.5-2 times differ. Essential turbulence intensification in front of the entrance telescope mirror when dome opening is ascertained. Strongly unstable stratification near the receiver is observable, caused by the stair opening in the concrete floor of the dome, which can result in intensification of the refractive index fluctuations in the presence of even small heat sources. Conclusions are drawn from the measurements, which can be related to all telescope of the considered class. It is necessary to prevent foreign heat sources in the dome and block warmer airflows from the stair opening; astronomical observations are to be carried out after completion of transient processes related to the dome opening.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Solar EUV band has a very important meaning of detecting the physical processes and its controlling factors of solar surface, and the Earth's environment as well as changes in the Earth's climate. In the thesis we introduce the basic design of the solar ultraviolet telescope and imaging system .Because of small-band transmission of the vacuum ultraviolet optical prism, we take double-Cassegrain reflector optical system. The sunlight could be gathered to CCD detection system in order to image the sun in three specific spectrums involving 30.4nm, 58.4nm and 121.6nm. The reason we choose the center wavelength of 30.4 nm. 58.4nm and 121.6nm is that these three spectrums contain a lot of bright lines, have a great radiation flux and play a significant role in ionizing and heating the Earth's upper atmosphere. We make UV telescope imaging system and ultraviolet light as a whole, then pump the whole system into vacuum to simulate space environment. We introduce the calibration device in our system innovatively. Our thesis gives a detailed description of the way of simulation of optical design, the vacuum system design and system calibration. Owing that our system have the characteristic of Lightness, simple structure, small power, it is rather fit for astronomical observations on the moon. The imaging results could provide very important research data for the middle and upper atmospheric composition and ionospheric electron changes in density and communications research.

The NASA Solar Dynamics Observatory (SDO), scheduled for launch in early 2009, incorporates a suite of instruments including the EUV Variability Experiment (EVE). Two channels of EVE, the Multiple EUV Grating Spectrograph (MEGS) A and B channels use concave reflection gratings to image solar spectra onto CCDs to measure the solar extreme ultraviolet (EUV) irradiance from 5 to 105 nm. MEGS provides these spectra at 0.1nm spectral resolution every 10 seconds with an absolute accuracy of better than 25% over the SDO 5-year mission. The calibration of the MEGS channels in order to convert the instrument counts in to physical units of W/m2/nm was performed at the National Institute for Standards and Technology (NIST) Synchrotron Ultraviolet Radiation Facility III (SURF III) located in Gaithersburg, Maryland. Although the final post-environmental calibrations have yet to be performed, preliminary results from the pre-environmental calibrations show very good agreement with the theoretical optical design given by Crotser et al. Further analysis is still needed in regards to the higher order contributions to determine the final first order QT for all channels, but two techniques are currently being analyzed and show promising results.

In-situ instrumentation for proposed future solar and heliophysics missions close to the sun, e.g., ESA's Solar Orbiter and NASA's Solar Sentinels, have challenging requirements. Notably, the two major challenges are the large dynamic range required to be covered and the mission lifetime. For example, the proposed orbit of Solar Orbiter ranges from 0.22 AU to 1.39 AU, resulting in up to 2 orders of magnitude change in flux that the instrument is required to handle, with a proposed mission life of greater than 10 years. We present details of a prototype instrument that is currently being developed to address some of these challenges. The instrument is a conventional "top-hat" type symmetric quadrispheric analyzer with a pair of electrostatic deflector plates designed to accept approximately ± 40° in elevation. Optimization of the geometry of the deflector plates will be discussed and preliminary results of the performance of the instrument will be presented. In addition, some of the other techniques and strategies that will be required to deliver the necessary performance will also be discussed.

An image stabilization system has been developed and demonstrated for solar observations in the visible wave-length at Udaipur Solar Observatory (USO) with a 15 cm Coude-refractor. The softwa4re and hardware components of the system are similar to that of the low cost solar adaptive optics system developed for the 1.5 m McMath-Pierce solar telescope at Kitt Peak observatory for solar observations in the infrared. The first results presented. The system has a closed loop correction bandwidth in the range of 70 to 100 Hz. The root mean by a factor of 10 to 20. The software developes and key issues concerning optimum system performance have been addressed.

A Multi-Application Solar Telescope (MAST) is proposed to be installed at the Udaipur Solar Observatory (USO) in India to monitor the Sun in optical and near infra-red wavelengths. The median value of the Fried's parameter at this site is 4 cm. USO is in the process of building an Adaptive optics (AO) system in order to have diffraction limited performance of the MAST under this moderate seeing condition. AO helps in achieving high-resolution imaging by compensating the atmospheric turbulence in real-time. We have performed simulations to evaluate the performance of AO for various seeing conditions. It was concluded that with the present availability of AO system components, a 55 cm aperture telescope would yield optimum performance with AO, in combination with post-processing techniques like speckle imaging and phase diversity. At present, we are developing a proto-type AO system at USO to demonstrate its performance with a 15 cm Coude´ refracting telescope as a preparation for the main AO system to be deployed on the MAST. The prototype AO system is being realized in two phases. In the first phase, we have developed an image stabilization system to compensate the global tilt of the wave-front. The second phase consists of sensing and correcting the local tilts of the wave-front by integrating a micro-machined membrane deformable mirror with the image stabilization system and is currently in progress. Here, we present the details of our proto-type AO system. We also present preliminary results obtained from simulations using Phase Diversity as a post processing technique.

The NASA Solar Dynamics Observatory (SDO), scheduled for launch in 2009, incorporates a suite of instruments including the EUV Variability Experiment (EVE). The EVE instrument package contains grating spectrographs that will measure the solar extreme ultraviolet (EUV) irradiance from 0.1 to 105 nm. The Multiple EUV Grating Spectrograph (MEGS) channels use concave reflection gratings to image solar spectra onto CCDs. MEGS will provide 0.1nm spectral resolution between 5-105nm every 10 seconds with an absolute accuracy of better than 25% over the SDO 5- year mission. MEGS-A utilizes a unique grazing-incidence, off-Rowland circle (RC) design to minimize angle of incidence at the detector while providing ≥ 0.1nm resolution between 5-37 nm. MEGS-B utilizes a double-pass, cross-dispersed double-Rowland circle design while providing ≥ 0.1nm resolution between 35-105 nm. We present the as-built performance of the MEGS optical design, including spectral resolution, wavelength shift, focus and alignment.

The zero expansion glass ceramic material, ZERODUR®, is well known for night-time telescope mirror substrates. Also for solar telescopes ZERODUR® is often selected as mirror blank material. Examples are the Swedish 1 m Solar Telescope (SST), the balloon-born telescope SUNRISE, and the New Solar Telescope (NST) of the Big Bear Solar Observatory. The properties of ZERODUR® are discussed with respect to the special technical requirements of solar observatories, resulting in the conclusion that mirrors made of this glass ceramic material are an excellent choice for solar telescopes.

The NASA Solar Dynamics Observatory (SDO), scheduled for launch in 2009, incorporates a suite of instruments including the EUV Variability Experiment (EVE). The Multiple EUV Grating Spectrograph (MEGS) channels use concave reflection gratings to image solar spectra onto CCDs that are operated at -100°C. MEGS provides 0.1nm spectral resolution between 5-105nm every 10 seconds with an absolute accuracy of better than 25% over the SDO 5- year mission. Characterizations and selection testing of the CCDs and the thin foil filters for SDO EVE have been performed with both in-band and visible illumination. CCD selection was based on results from testing in LASP facility Calibration and Test Equipment (CTE3) as well as results from at testingMIT. All CCDs meet the requirements for electronics gain, flat field, Quantum Efficiency (QE), dark current, reverse clock, CTE, bad pixels and the -120°C survival test. The thin foil filters selection was based on tests performed at LASP facilities and NIST. All filters provide >106 attenuation of visible light with the proper EUV transmission needed for order sorting capabilities and are free of critical pinholes.

Zoom lenses are usually designed for a specified waveband and change magnification, and thus resolution, for different object sizes or different object distances. However, the Advanced Technology Solar Telescope (ATST)/ Visible Light Broadband Imager (VLBI), under development by the National Solar Observatory, require constant resolution for different wavelengths over a wide spectral range (388.3 nm 3o 854.2 nm). An eight-element zoom lens meeting this requirement is presented, and yields diffraction-limited performance over the field of view at nine specific wavelength/zoom positions. Each zoom position, corresponding to a specific wavelength, has a focal length and f/number for achieving constant CCD sampling. The Strehl ratio of the telescope is greater than 90% over all zoom positions.

The AZT-33 astronomic telescope has been testes at Sayan solar observatory (Institute of Solar-Terrestrial Physics SB RAS) with respect to the characteristics of intradome airflows, affecting the image quality. From the results of testing the airflows in the telescope, some conclusions have been drawn, which allow the quality of astronomic images in telescopes similar to AZT-33 to be improved. For example, there should be no foreign heat sources inside the telescope dome during measurements. This means that measures should be undertaken to remove open slits in the concrete floor and to block out warm airflows from the stair well. In addition, measurements should be carried out only after the transient processes associated with the opening of the dome slit are fully accomplished.

The New Solar Telescope (NST) project at Big Bear Solar Observatory (BBSO) now has all major contracts for design and fabrication in place and construction of components is well underway. NST is a collaboration between BBSO, the Korean Astronomical Observatory (KAO) and Institute for Astronomy (IfA) at the University of Hawaii. The project will install a 1.6-meter, off-axis telescope at BBSO, replacing a number of older solar telescopes. The NST will be located in a recently refurbished dome on the BBSO causeway, which projects 300 meters into the Big Bear Lake. Recent site surveys have confirmed that BBSO is one of the premier solar observing sites in the world. NST will be uniquely equipped to take advantage of the long periods of excellent seeing common at the lake site. An up-to-date progress report will be presented including an overview of the project and details on the current state of the design. The report provides a detailed description of the optical design, the thermal control of the new dome, the optical support structure, the telescope control systems, active and adaptive optics systems, and the post-focus instrumentation for high-resolution spectro-polarimetry.

We present the basic design of the THermal Control System (THCS) for the 1.6-meter New Solar Telescope (NST) at the Big Bear Solar Observatory (BBSO), California. The NST is an off-axis Gregorian telescope with an equatorial mount and an open support structure. Since the telescope optics is exposed to the air, it is imperative to control the local/dome seeing, i.e., temperature fluctuations along the exposed optical path have to be minimized. To accomplish this, a THCS is implemented to monitor the dome environment and interact with the louver system of the dome to optimize instrument performance. In addition, an air knife is used to minimize mirror seeing. All system components have to communicate with the Telescope Control System (TCS), a hierarchical system of computers linking the various aspects of the entire telescope system, e.g., the active mirror control, adaptive optics, dome and telescope tracking, weather station, etc. We will provide an initial thermal model of the dome environment and first measurements taken in the recently replaced BBSO dome.

The New Solar Telescope at Big Bear Solar Observatory will use a distributed system to control the telescope, dome, adaptive optics, thermal environment and instrumentation. The Telescope Pointing and Tracking Subsystem has the tasks of controlling the telescope dome and acting as a wrapper for the telescope mount software (provided by the mount manufacturer) and adding the specific control features needed for a large solar telescope. These include features for offset pointing to specific regions on the solar disk, safety interlock systems for the primary mirror, and provision for the alignment of the relatively small dome opening with the telescope optical axis.

The New Solar Telescope (NST) is an advanced solar telescope at Big Bear Solar Observatory (BBSO). It features a 1.6-m clear aperture with an off-axis Gregorian configuration. An open structure will be employed to improve the local seeing. The NST Telescope Control System (TCS) is a complex system, which provides powerful and robust control over the entire telescope system. At the same time, it needs to provide a simple and clear user interface to scientists and observers. We present an overview of the design and implementation of the TCS as a distributed system including its several subsystems such as the Telescope Pointing and Tracking Subsystem, Wavefront Sensing Subsystem etc. The communications between different subsystems are handled by the Internet Communication Engine (Ice) middleware.

The New Solar Telescope (NST) is an innovative 1.6-meter, off-axis, open telescope currently being developed and built at the Big Bear Solar Observatory (BBSO). The observatory is situated on a small peninsula in Big Bear Lake, a mountain lake at an altitude of about 2100 m in the San Bernardino Mountains of Southern California. The lake effectively suppresses the boundary layer seeing. Thus, providing consistently very good daytime seeing conditions. BBSO has been identified by the site survey for the Advanced Technology Solar Telescope (ATST) as one of the best sites for solar observations. It is uniquely qualified for long-duration observations requiring high-spatial resolution. This type of observations is typically encountered in solar activity monitoring and space weather forecast. The ATST site survey has collected more than two years of data linking seeing conditions to geographical parameters and local climate. We have integrated these data in a MySQL database and we will use this information in connection with a real-time seeing monitor and weather station to predict the seeing conditions at Big Bear such that scheduling and prioritization of observing programs (e.g., synoptic vs. high-resolution modes) becomes possible.

Ground-based telescopes can achieve diffraction-limited images when equipped with adaptive optics (AO). A major limitation of AO is the small field of view, which is due to the limited isoplanatic patch size. Nevertheless, conventional long-slit spectrographs cannot sample the entire AO-corrected field of view in a single exposure. However, equipped with a modern, large detector array, the Integral Field Unit (IFU) technique will allow a 3-dimensional (3-D) data cube to be recorded simultaneously over the entire AO corrected field of view, with a conventional long-slit spectrographs. We are building a state-of-the-art image slicer IFU for the National Solar Observatory's (NSO) McMath-Pierce Solar Telescope (McMP). This will be the first time that an advanced image slicer IFU is used for 3-D spectroscopy and polarimetry at a solar telescope. The IFU consists of 25 slices that will sample a 6.25" x 8" AO corrected field of view simultaneously, and produces a 200" long slit for diffraction-limited 3-D spectroscopy and polarimetry. This IFU 3-D technique will provide the most high spatial, high temporal resolution with high throughput for solar spectroscopy and polarimetry. This is critical for state-of-the-art spectral diagnosis of solar velocity and magnetic fields. We discuss the design, construction, and testing of this new IFU.

An important part of a large solar telescope is the ability to correct, in real time, optical alignment errors caused by gravitational bending of the telescope structure and wavefront errors caused by atmospheric seeing. The National Solar Observatory is currently designing the 4 meter Advanced Technology Solar Telescope (ATST). The ATST wavefront correction system, described in this paper, will incorporate a number of interacting wavefront control systems to provide diffraction limited imaging performance. We will describe these systems and summarize the interaction between the various sub-systems and present results of performance modeling.