The Air Force/NASA Solar Mass Ejection Imager (SMEI) launched January 6, 2003 is now recording whole sky data on each 100-minute orbit. Precise photometric sky maps of the heliosphere around Earth are expected from these data. The SMEI instrument extends the heritage of the HELIOS spacecraft photometer systems that have recorded CMEs and other heliospheric structures from close to the Sun into the anti-solar hemisphere. SMEI rotates once per orbit and views the sky away from Earth using CCD camera technology. To optimize the information derived from this and similar instruments, a tomographic technique has been developed for analyzing remote sensing observations of the heliosphere as observed in Thomson scattering. The technique provides 3-dimensional reconstructions of heliospheric density. The tomography program has been refined to analyze time-dependent phenomena such as evolving corotating heliospheric structures and more discrete events such as coronal mass ejections (CMEs), and this improved analysis is being applied to the SMEI data.

Our tomographic techniques developed over the last few years are based on kinematic models of the solar wind. This allows us to determine the large-scale three-dimensional extents of solar wind structures using interplanetary scintillation (IPS) observations and Thomson scattering brightness data in order to forecast their arrival at Earth in real time. We are specifically interested in a technique that can be combined with observations presently available from IPS velocity data and with observations which will become available from the Solar Mass Ejection Imager. In this paper, we introduce magnetic field projections from solar surface magnetogram data using the Stanford Current-Sheet Source Surface model at the source surface of our model and extrapolate the magnetic field out to and beyond Earth. The results are compared with in situ data. Real time projections of these data are available on our web site at: http://cassfos02.ucsd.edu/solar/forecast/index_v_n.html and http://cassfos02.ucsd.edu/solar/forecast/index_br_bt.html

The solar Total Irradiance Monitor (TIM) on NASA's SORCE mission began taking data in early 2003. This instrument continues the 25-year record of space-borne, total solar irradiance (TSI) measurements, with improved precision from its new technologies and calibration methods. We present an overview of the TIM instrument, including the design features enabling its high precision, and we present preliminary on-orbit TSI data.

The LASCO-C2 coronagraph onboard the SOHO solar probe have been providing for the last seven years an unprecedented long sequence of coronal images at high cadence (about 75 images/day). The LASCO-C2 calibrations included the determination of the geometric characteristics (attitude, distortion) as well as the photometric and photopolarimetric responses. Such calibrations needed resort to a complementary set of approaches including optical-modelling, pre-flight measures and in-orbit measures and monitoring. In this paper we discuss about the specific contribution of each of them, the example of radiometric calibration of LASCO-C2 is dominated by the strong vignetting induced by the occultors. The occultors fully mask the extended circular area centered on the Sun image. Due to operational constraints the vignetting function has been obtained using a complementary set of approaches: 1) ray tracing, 2) the geometric convolution of diaphragms, 3) the measure of uniform sources in laboratory, 4) the measures in orbit of the stars and F-corona. Finaly the relationship of radiometry with geometric calibrations, strylight calibration and the log term stability monitoring is discussed.

The primary scientific objective of RHESSI Small Explorer mission is to investigate the physics of particle acceleration and energy release in solar flares, through imaging and spectroscopy of X-ray/gamma-ray continuum and gamma-ray lines emitted by accelerated electrons and ions, respectively. RHESSI utilizes rotating modulator collimators together with cooled germanium detectors to image X-rays/gamma-rays from 3 keV to 17 MeV. It provides the first hard X-ray imaging spectroscopy, the first high resolution spectroscopy of solar gamma-ray liens, and the first imaging of solar gamma-ray lines and continuum. Here we briefly describe the mission and instrumentation, and illustrate its capabilities with solar and cosmic observations obtained in the first 17 months of operation.

The Solar Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory will characterize the dynamical evolution of the solar plasma from the chromosphere to the corona, and will follow the connection of plasma dynamics with magnetic activity throughout the solar atmosphere. The AIA consists of 7 high-resolution imaging telescopes in the following spectral bandpasses: 1215Å. Ly-a, 304 Å He II, 629 Å OV, 465 Å Ne VII, 195 Å Fe XII (includes Fe XXIV), 284 Å Fe XV, and 335 Å Fe XVI. The telescopes are grouped by instrumental approach: the MAGRITTE Filtergraphs (R. MAGRITTE, famous 20th Century Belgian Surrealistic Artist), five multilayer EUV channels with bandpasses ranging from 195 to 1216 Å, and the SPECTRE Spectroheliograph with one soft-EUV channel at OV 629 Å. They will be simultaneously operated with a 10-second imaging cadence. These two instruments, the electronic boxes and two redundant Guide Telescopes (GT) constitute the AIA suite. They will be mounted and coaligned on a dedicated common optical bench. The GTs will provide pointing jitter information to the whole SHARPP assembly. This paper presents the selected technologies, the different challenges, the trade-offs to be made in phase A, and the model philosophy. From a scientific viewpoint, the unique combination high temporal and spatial resolutions with the simultaneous multi-channel capability will allow MAGRITTE / SPECTRE to explore new domains in the dynamics of the solar atmosphere, in particular the fast small-scale phenomena. We show how the spectral channels of the different instruments were derived to fulfill the AIA scientific objectives, and we outline how this imager array will address key science issues, like the transition region and coronal waves or flare precursors, in coordination with other SDO experiments. We finally describe the real-time solar monitoring products that will be made available for space-weather forecasting applications.

The next generation of the National Oceanic and Atmospheric Administration's (NOAA) Geo-Stationary Operational Environmental Satellite (GOES) spacecraft will include an X-ray telescope that will monitor the Sun for predicting solar energetic events and for providing information about the large-scale solar magnetic field. The Solar X-ray Imager that will be flown on the GOES N spacecraft in late 2004 makes use of a super-polished grazing incidence mirror, a highly efficient back-thinned CCD, and thin metalized filters to observe the million-degree corona with 10-arcsec resolution (5 arcsec pixel size). Full-sun images will be acquired with SXI on a one-minute cadence at wavelengths between approximately 10 and 60 Å. SXI data will be used to forecast 'space weather', i.e., the effects of charged particles that are produced at the Sun as they interact at the earth. Major contributors to space weather include: variations in the Sun's solar wind, solar flares, and solar mass ejections. Effects of space weather include: radiation damage and particle events in high-inclination orbit spacecraft, disruption of various kinds of communications equipment, degradation of navigational tools such as GPS, potential health hazards during space walks, and power blackouts. Data acquired by the SXI will additionally provide invaluable context information for upcoming solar missions such as STEREO and SDO. The Lockheed Martin Solar and Astrophysics Laboratory has prepared two flight model SXIs that are being readied for flight on the GOES N and GOES O or P spacecraft.

A new Solar X-ray Imager (SXI) using back-illuminated, anti-blooming CCD technology will become part of the instrument complement on NOAA's GOES (Geosynchronous Orbiting Environmental Satellite) N and O spacecraft, with probable launch dates beginning in the 2004-2005 time frame. SXI N and O were developed under a NASA contract by the Solar and Astrophysics Laboratory at the Lockheed Martin Advanced Technology Center, and are currently being integrated into their respective spacecrafts by Boeing Space Systems. SXI N and O will each provide full disk images of the Sun from 0.2 to 1.2 keV (10-60 Å) through the combination of a grazing incidence telescope, bandpass filters, and an X-ray imaging CCD. The custom designed, back-illuminated CCDs were fabricated and initially tested by Marconi Technologies (formerly EEV Ltd, now e2v technologies), screened in visible light by the Mullard Space Science Laboratory, and fully characterized in both visible light and X-rays at LMSAL. By minimizing the field-free region within the CCD, the spatial resolution at low X-ray energies was significantly improved. The SXI CCDs also exhibit only very modest response changes as a result of solar X-ray exposure, based upon extended life tests. The flight CCDs meet or surpass all specifications for quantum efficiency (QE), spatial uniformity, defects, charge transfer efficiency, QE stability in vacuum, read noise, linearity, full well and dark current. A QE model based on earlier work with ion-implanted, laser-annealed CCDs provides a consistent picture of the CCD response from soft X-rays through far UV wavelengths.

The X-ray calibration of the GOES Solar X-ray Imagers (SXI) was accomplished at the component level and at the instrument level. The CCD and thin film filters were characterized in the facilities at the Lockheed Martin Solar and Astrophysics Laboratory. The grazing incidence telescope mirrors and the completed instruments were calibrated at the X-ray Calibration Facility (XRCF) at NASA’s Marshall Space Flight Center. The XRCF consists of an X-ray source at one end of a 518 m long evacuated tube and a large vacuum chamber at the opposite end. The X-ray source has a variety of interchangeable anodes and filters to provide filtered characteristic K- and L-shell line emission in the range from 0.109 to 8.6 keV. The absolute Photometric calibration of the SXI telescopes is very important for analysis and interpretation of their data, and to monitor the long-term solar variations at X-ray wavelengths. This paper describes the results of these calibrations.

A jitter compensation system is incorporated in the Solar X-ray Imager (SXI) that will be mounted to the solar array wing of the GOES N spacecraft, the next in the series of NOAA weather satellites. The SXI obtains images in a back-thinned CCD with 5 arcsec pixels. The SXI incorporates a pointing aspect sensor manufactured by the Adcole Corporation that is used in a semi-closed loop system with the SXI flight computer to shift the detected image during an exposure along the readout columns of the CCD in order to compensate for jitter in one dimension. Simulations of the predicted motions caused by the GOES spacecraft and self-induced by the SXI filter wheels indicate that the jitter as experienced by the SXI instrument will be primarily along one axis, parallel to the east-west direction, with amplitudes in the tens of arcseconds and with dominant frequencies less than approximately 10 Hz. The SXI CCD columns are aligned along this direction in order to make possible on-chip compensation. The SXI motion compensation system has been evaluated with realistic models for the expected spacecraft jitter and assuming a performance algorithm for the SXI instrument. Our analysis indicates that the X-ray spatial imaging performance will be improved when the jitter compensation system is used. We discuss the design and analysis predictions.

The Extreme Ultraviolet Imager (EUVI) is part of the SECCHI instrument suite currently being developed for the NASA STEREO mission. Identical EUVI telescopes on the two STEREO spacecraft will study the structure and evolution of the solar corona in three dimensions, and specifically focus on the initiation and early evolution of coronal mass ejections (CMEs). The EUVI telescope is being developed at the Lockheed Martin Solar and Astrophysics Lab. The SECCHI investigation is led by the Naval Research Lab. The EUVI’s 2048 x 2048 pixel detectors have a field of view out to 1.7 solar radii, and observe in four spectral channels that span the 0.1 to 20 MK temperature range. In addition to its view from two vantage points, the EUVI will provide a substantial improvement in image resolution and image cadence over its predecessor SOHO-EIT, while complying with the more restricted mass, power, and volume allocations on the STEREO mission.

Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission, the Solar Orbiter will study the Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the probe to within 45 solar radii (0.21 AU) of our star, and to solar latitudes as high as 38°. The scientific payload to be carried by the Orbiter will include a sophisticated remote-sensing package, as well as state-of-the-art in-situ instruments. Given the technical and financial constraints associated with this mission, it is essential that key technologies requiring significant development be identified as early as possible. ESA has therefore set up a Payload Working Group (PWG), made up of members of the scientific community with expertise in instrumentation of the kind envisaged for the Solar Orbiter. The tasks of the PWGs included: 1) a realistic assessment of the strawman payload, including definition of mass, size, power requirements; 2) identification of key problem areas arising as a result of the extreme thermal and radiation environments; 3) identification of necessary technological developments; and 4) provision of detailed input to a Solar Orbiter Payload Definition Document (PDD). This contribution summarizes the activities and findings by the Solar Orbiter Payload Working Group.

The SIde-Looking Coronagraph (SILC) is one of the solar remote-sensing instruments proposed for the payload of the Solar Orbiter mission. The Solar Orbiter is a mission selected in September 2000 by the European Space Agency (ESA) for the definition study phase. The Solar Orbiter will describe elliptic orbits with a large range of heliocentric distance, from 0.21 to 0.6 AU (astronomical units), that is a factor 3 for the geometric conditions and will reach heliographic latitudes as high as 38 degrees. Furthermore, the spacecraft will have offset pointing capability so as to target any point of the solar disk. These constraints (in addition to the severe thermal environment) lead us to propose an externally occulted coronagraph entirely protected from direct sunlight by remaining in the shadow of the spacecraft and looking sideways. The optical design follows the general principles of an externally-occulted coronagraph adapted to the side-looking concept. Although SILC loses the full spatial coverage of the corona, it can observe the inner part of the corona (down to 1.5R) during the whole mission and compensate the off-pointing of the spacecraft in the two directions. The performances, resulting from ray-tracing calculations, are presented here together with the expected stray light level.

We report on the concept design and the theoretical ray trace analysis of the complex solar X-ray and EUV imaging telescope (CSIT) which is composed of a grazing incidence optical system and a normal incidence optical system. The CSIT can image the full sun in the wavelength bands from 0.4 to 6 nm and one EUV wavelength of 19.5nm with the same detector. The CSIT is a compact structure and can satisfy top-level image quality requirements.

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 Sun is an ideal object for the development and application of Multi-Conjugate Adaptive Optics (MCAO). An effort to develop solar MCAO is pursued by the NSO’s Adaptive Optics Project. In developing solar MCAO we bear in mind its possible implementation into the proposed 4-M Advanced Technology Solar Telescope (ATST). Two possible relay optical designs feeding a MCAO section and the Coudé section of a 4-M off-axis solar telescope, such as the proposed ATST, are presented and discussed here.

The National Solar Observatory and the New Jersey Institute of Technology have developed two 97 actuator solar adaptive optics (AO) systems based on a correlating Shack-Hartmann wavefront sensor approach. The first engineering run was successfully completed at the Dunn Solar Telescope (DST) at Sacramento Peak, New Mexico in December 2002. The first of two systems is now operational at Sacramento Peak. The second system will be deployed at the Big Bear Solar Observatory by the end of 2003. The correlating Shack-Hartmann wavefront sensor is able to measure wavefront aberrations for low-contrast, extended and time-varying objects, such as solar granulation. The 97-actuator solar AO system operates at a loop update rate of 2.5 kHz and achieves a closed loop bandwidth (0dB crossover error rejection) of about 130 Hz. The AO system is capable of correcting atmospheric seeing at visible wavelengths during median seeing conditions at both the NSO/Sacramento Peak site and the Big Bear Solar Observatory. We present an overview of the system design. The servo loop was successfully closed and first AO corrected images were recorded. We present first results from the new, high order AO system.

Multiconjugate adaptive optics has been proposed in order to extend the size of the corrected field of view with respect to the classical AO field of view. In order to achieve this, a three dimensional measurement of the turbulent volume is needed to collect the information to command the several deformable mirrors. This can be done by using tomography, in which several WFS are used, each of them coupled to a sky region. Here we report the experimental demonstration of such evaluation for solar observations. In addition, we confront these results on turbulence distribution with a study of AO corrected images by using multi point large field of view wavefront sensing with the new Dunn Solar Telescope adaptive optics system. This yields to information on the AO system performances and provide useful estimate of the PSF variation across the field. The results from this article provides an important step forward for building a full solar multi-conjugate adaptive optics system for the Dunn Solar Telescope and in a longer term for the future 4 meter ATST telescope.

In nighttime astronomy Vernin and co-workers have proposed and subsequently developed the so-called SCIDAR (SCIntillation Detection And Ranging) technique to probe C_n²(h). It makes use of the double shadow band (or scintillation) pattern formed on a telescope aperture by the two components of a binary star. We are developing a variant of this technique for solar astronomy. It uses pairs of small apertures on the solar image with diameters smaller than the isoplanatic patch (“artificial double stars”). Within the isoplanatic patch the complex amplitude (intensity and phase) of the atmospheric wavefront disturbances is constant. Solar SCIDAR (or S-SCIDAR) makes use of this. We will present the results of the first (inconclusive) experiments of this S-SCIDAR technique as used on the 76 cm aperture Dunn Solar Telescope (DST) and the 152 cm aperture McMath-Pierce facility (McM-P) of the US National Solar Observatory. It uses a 45 x 45 lenslet array placed in the solar image. The size of the lenslets corresponds to 2.25 x 2.25 arcsec at the DST and 1.67 x 1.67 arcsec at the McM-P; the separation of lenslet pairs on the DST (and hence of the separations of the artificial double stars) ranges from 2.25 arcsec to 140 arcsec. The lenslet array forms an array of pupil images on a CCD detector.

Meter Aperture Solar Telescope (MAST) is a proposed modern solar telescope equipped with Adaptive Optics (AO) facility for observing the Sun in Optical and infra-red wavelengths. It is planned to develop a low-order AO system at the re-imaged pupil plane of the MAST. Before developing such an AO system, one would like to answer a few questions like what is the size of the sub-apertures required to achieve optimum performance under typical seeing conditions? What is the required bandwidth? Is it possible to operate the system with a narrow bandwidth of 0.1 nm? Is it possible to achieve diffraction limited imaging by using speckle imaging on the low-order AO corrected images? In this paper, we try to answer these questions through extensive computer simulations and arrive at a final optimal specification ot the low-order AO system of the MAST. We simulate distorted wave-fronts for various seeing conditions (for both Kolmogorov and von Karman spectrum) using large phase screens generated using Fourier transfrom method. We find the local slopes of the distorted wave-front over the sub-apertures of different lenslet array geometries using a least square modal recontruction method. Then we estimate the structure functions, optical transfer functions, Strehl resolution of the corrected wave-front and evaluate the performance. We have developed a speckle-masking code and parallelised it using a 16-processor IBM-SP machine. We use a series of AO corrected images to obtain a speckle reconstruction of the object. We evaluate the performance of this hybrid imaging system in achieving diffraction limited imaging of small-scale solar features.

The National Solar Observatory in collaboration with the High-Altitude Observatory is developing a new solar polarimeter, the Diffraction Limited Spectro-Polarimeter. In conjunction with a new high-order adaptive optics system at the NSO Dunn Solar Telescope, the DLSP design facilitates very high angular resolution observations of solar vector magnetic fields. This project is being carried out in two phases. As a follow-on to the successful completion of the first phase, the ongoing DLSP Phase II implements a high QE CCD camera system, a ferro-electric liquid crystal modulator, and a new opto-mechanical system for polarization calibration. This paper documents in detail the development of the modulator system and its performance, and presents preliminary results from an engineering run carried out in combination with the new NSO high-order AO system.

Solar ultraviolet imaging instruments in space pose most demanding requirements on their detectors in terms of dynamic range, low noise, high speed, and high resolution. Yet UV detectors used on missions presently in space have major drawbacks limiting their performance and stability. In view of future solar space missions we have started the development of new imaging array devices based on wide band gap materials (WBGM), for which the expected benefits of the new sensors - primarily visible blindness and radiation hardness - will be highly valuable. Within this initiative, called “Blind to Optical Light Detectors (BOLD)”, we have investigated devices made of AlGa-nitrides and diamond. We present results of the responsivity measurements extending from the visible down to extreme UV wavelengths. We discuss the possible benefits of these new devices and point out ways to build new imaging arrays for future space missions.

C³Po is a concept for a novel array detector concept that is optimized for highly sensitive and precise differential imaging such as needed for astrophysical polarimetry. Chopping between two or more independent image states (such as four linearly independent polarization states) can be performed at speeds in the kHz domain to provide virtually simultaneous images without the need to read out the array at kHz frame rates. This allows the technology to be applied to large arrays with precise, slow readouts. All independent image planes are observed with the same physical pixel on the detector, which renders normalized differences between image planes insensitive to the gain of individual pixels. The detector concept has 100% geometrical fill factor and a quantum efficiency approaching unity. The technology can be applied to silicon to cover the 200-1100 nm wavelength range, and to infrared-sensitive materials such as HgCdTe or InSb for the 1-20 μm wavelength range. While the detector concept has a wide range of potential applications outside of astronomy, we focus here on its application to polarimetric observations of the Sun.

A new concept CCD camera is currently under development at the XUVLab of the Department of Astronomy and Space Science of the University of Florence. This CCD camera is the proposed detector for the space- and ground-based solar corona observations. This camera will be the detector for the polarimetric channels of the UVC coronagraph of the HERSCHEL rocket mission to observe the solar corona in an optical broadband. The ground-based application consists in a UVC prototype for coronagraphic measurements from Earth in the visible range. Within this project, a CCD camera with innovative features has been produced: the camera controller allows the fine tuning of all the parameters related to charge transfer and CCD readout, i.e., the use of virtually any CCD sensor, and it implements the new concept of high level of versatility, easy management, TCP/IP remote control and display.

The National Solar Observatory operates two facilities with demanding needs for rapid image collection (i.e. > television frame rates). The first is GONG, a global network of six identical small telescopes devoted to nearly continuous observations of the sun's surface vibrations in order to study its internal properties by helioseismology. The second, SOLIS, is a suite of three instruments that collects images and spectra of the sun needed to study the behavior of solar activity on time scales of minutes to decades. Five different types of cameras are installed in these instruments. High speed, high sensitivity, large dynamic range, and good photometric performance are key factors for cameras used to make measurements of subtle solar signals that pass through the noisy terrestrial atmosphere. A camera that combines all these characteristics is elusive. The combination of high speed and good photometric performance, when observing small intensity changes, is particularly hard to get in practice. High speed in large format CCD and hybrid FPA cameras is achieved by dividing the array into multiple channels that are read simultaneously. An unwanted result of this technique is cross talk between signal channels. It is of order 1 percent in the case of Silicon Mountain Design 1M60_20 cameras (1k x 1k, 60 fps) and Rockwell Scientific Company HyViSI-1024 cameras (1k x 256, 92 fps). Cross talk (and also successive-frame image retention) are particularly hard to deal with since they may exhibit non-linear characteristics that depend on illumination light level. We describe these and other phenomena, attempts to mitigate the effects, and results from solar observations.

In order to have affordable light-weight hard (30 keV or higher) X-ray mirrors for solar physics studies, it is necessary to use metal replicated mirrors. However these mirrors have never been made to the exacting requirements of solar physics which is a 1 arc second point spread function half energy width. An exciting breakthrough can be achieved by making mirrors with current technology by measuring their figure and then judiciously deforming them as is traditionally done for visible light adaptive optics mirrors. As a first step in this project, an electroformed Wolter type I mirror was used to focus and image X-rays onto a CCD X-ray camera. Two sets of data necessary to characterize the mirror figure were acquired: (1) a series of in and out of focus images along the optical axis taken to allow for a deconvolution technique to determine the figure; (2) a series of in focus images taken at different energies (0.28-4.5 keV) so as to be able to correct for surface scatter effects on top of geometrical effects. A report on the analysis of these results and a discussion of preliminary actuator designs are given.

We demonstrate a software application designed for the display and interactive manipulation of 3D heliospheric volume data, such as solar wind density, velocity and magnetic field. The Volume Explorer software exploits the capabilities of the Volume Pro 1000 (from TeraRecon, Inc.), a low-cost 64-bit PCI board capable of rendering a 512-cubed array of volume data in real time at up to 30 frames per second on a standard PC. The application allows stereo and perspective views, and animations of time-sequences. We show examples of three-dimensional heliospheric volume data derived from tomographic reconstructions based on heliospheric remote sensing observations of the heliospheric density and velocity structure. Currently these reconstructions are based on archival IPS and Thomson scattering data. In the near future we expect to add reconstructions based on the all-sky observations from the recently launched Solar Mass Ejection Imager.

Over the past years we have developed a tomographic technique for using heliospheric remote sensing observations (i.e. interplanetary scintillation and Thomson scattering data) for the reconstruction of the three-dimensional solar wind density and velocity in the inner heliosphere. We describe the basic algorithm on which our technique is based. To highlight the details of the reconstruction algorithm we specifically emphasize the implementation of corotating tomography using IPS g-level and IPS velocity observations as proxies for the solar wind density and velocity, respectively. We provide some insight into the modifications required to expand the technique into a fully time-dependent tomography, and to use Thomson scattering brightness (instead of g-level) as a proxy for the solar wind density.

The LYOT (LYman Orbiting Telescope) solar mission (proposed for a CNES micro-satellite) is composed of a disk imager and a coronagraph, both working at Lyman-α (121.6 nm). The coronagraph is internally occulted and all-reflective with a field-of-view of 1.2 R up to 2.5 R and high spatial resolution (2 pixels) amounts to 5 arcsec. The optical design is driven by the requirement to use a superpolished spherical mirror to minimize the scattered light into the instrument. The LYOT mission will observe the Lyman-α corona at high cadence (1 image/5 minutes) over a period of two years.

The InfraRed Imaging Magnetograph (IRIM) is a high temporal resolution, high spatial resolution, high spectral resolving power, and high magnetic sensitivity solar two-dimensional narrow-band spectro-polarimeter working in the near infrared from 1.0 μm to 1.7 μm at Big Bear Solar Observatory (BBSO). It consists of an interference filter, a polarization analyzer, a birefringent filter, and a Fabry-Perot etalon. As the narrowest filter of IRIM, the infrared Fabry-Perot plays a very important role in achieving the narrow band transmission of ~ 10 pm and high throughput between 85% and 95% for the full wavelength range, maintaining wavelength tuning ability from 1.0 to 1.7 μm, and assuring stability and reliability. As the third of a series of publications describing IRIM, this paper outlines a set of methods to evaluate the near infrared Fabry-Perot etalon. Two-dimensional characteristic maps of the near infrared Fabry-Perot etalon, including the bandpass ▵λ, effective finesse F_eff, peak transmission τ_max, along with a free spectral range, flatness, roughness, and stability and repeatability were obtained with laboratory equipment. These measured results will benefit the optimization of IRIM design and observational mode of the future.

This paper describes a versatile camera designed to operate at high frame rates of > 2kHz. Such high frame rates are required to reduce the latency, i.e., achieve high bandwidth in a solar adaptive optics application. The camera was designed around a 1280x1024 pixel CMOS 10-bit sensor with a readout rate of 2 microseconds per row. The output is switchable between a standard Camera Link interface with four 10-bit ports (standard camera mode) and a non-standard Camera Link interface with twelve 8-bit ports (adaptive optics mode). The programmable camera interface maps blocks of pixels to output ports enabling multiple regions of interest. This mode is of particular interest for solar multi-conjugate adaptive optics (MCAO). The speed of the camera is determined by the number of rows of pixels needed in the application. For example, a 200x200 pixel sub-array that is needed for the 97-actuator solar adaptive optics system at the Dunn Solar Telescope can be read out at a rate of 2.5kHz. Camera design and performance will be discussed.

SWAP (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument that has been selected to fly on the PROBA-II technology demonstration platform, a program of the European Space Agency (ESA) to be launched in 2006. This paper presents the instrument concept and its scientific goals. SWAP uses an off-axis Ritchey Chretien telescope that will image the EUV solar corona at 19.5 nm on a specifically fabricated extreme ultraviolet (EUV) sensitivity enhanced CMOS APS detector. This type of detector has advantages that promise to be very profitable for solar EUV imaging. The SWAP design is built on a similar concept as the MAGRITTE instrument suite for the NASA Solar Dynamics Observatory (SDO) mission to be launched in 2007. The optics have been adapted to the detector size. The SWAP PROBA-2 program will be an opportunity to demonstrate and validate the optical concept of MAGRITTE, while it will also validate space remote sensing with APS detectors. On the science outcomes, SWAP will provide solar corona images in the Fe XII line on a baselined 1-min cadence. Observations with this specific wavelength allow detecting phenomena, such as solar flares or 'EIT-waves’, associated with the early phase of coronal mass ejections. Image recognition software will be developed that automatically detects these phenomena and sends out space weather warnings. Different modules of this software will run both on the ground system as well as on the onboard computer of PROBA II. The SWAP data will complement the observations provided by SOHO-EIT, and STEREO-SECCHI.

GOES-12, the last of the GOES-8/9/10/11/12 series of spacecraft was modified to accommodate a Solar X-Ray Imager (SXI). Previous GOES spacecraft X-ray sensors provide only average numerical data flux values. The modifications required to accommodate the SXI impacted nearly every subsystem on the spacecraft. The SXI on GOES-12 has provided the first Solar X-Ray images taken from geostationary orbit. Full-disk solar X-ray images can be collected at approximately one-minute intervals. A combination of exposure time and filter selection will allow the exploration of the full range of solar X-ray features to be covered, including coronal holes, solar flares, and coronal mass ejections. The successive integration of the SXI into the GOES-12 X-Ray Positioner, Solar Array Yoke, and Solar Array was accomplished with common test and handling processes. Using the same procedures in both the high bay and thermal vacuum chamber facilities minimized the risk in handling and testing this one of a kind instrument. The GOES-12 spacecraft design incorporated an innovative means to provide a stable sun-pointing platform. The double step "deadbeat" stepping profile actively damps out Solar Array vibrations caused by tracking the Sun with the Solar Array and provides the stability to obtain the detailed images that are displayed on the NOAA/SEC GOES Solar X-ray Imager Web-site, http://www.sec.noaa.gov/sxi/latest.html.

An optical design for a modern off-axis 1.6 m clear aperture solar telescope - the NST (New Solar Telescope) is presented. The NST will replace the 65 cm vacuum telescope at Big Bear Solar Observatory (BBSO)in 2006. A high-order Adaptive optics (AO) system will deliver light to the current and planned complement of BBSO instrumentation. The NST will fully utilize the optical and dynamical range advantages of its unobstructed (off-axis) pupil.

Measurements of the EUV, visible and near-infrared grazing-incidence reflectivity of Si-Au coatings are presented. Such coatings could be used for EUV optical components subjected to very high thermal load, as the optics for the EUV spectrometer of the Solar Orbiter mission. The mission consists in putting an orbiting spacecraft in close proximity (45 solar radii) to the Sun, then in a severe thermal environment (34 kW/m²). The thermal stresses are reduced if the optics looking at the disk are operated in grazing incidence. The common materials used as a grazing-incidence coatings with high EUV reflectivity have low reflectivity in the visible and near-infrared, on the contrary materials with high visible grazing-incidence reflectivity have poor EUV reflectivity. A suitable coating with high reflectivity both in the EUV and visible is a silicon layer (100-400 Å) deposited on gold. The silicon has high EUV grazing-incidence reflectivity and is partially transparent in the visible and near-infrared, where the gold coating has high reflectivity. Measurements on Si-Au samples show both higher EUV reflectivity than gold samples and higher visible reflectivity than silicon samples.