This PDF file contains the front matter associated with SPIE Proceedings Volume 6689, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) developed for the NASA Solar Terrestrial Relations Observatory (STEREO) mission is a suite of optical telescopes that will, for the first time, observe the entire inner heliosphere from the solar surface out to the vicinity of Earth from twin spacecraft. SECCHI was developed by an international consortium led by the Naval Research Laboratory (NRL). The primary objective of the STEREO mission is to understand the Coronal Mass Ejection (CME) phenomenon, discovered in 1971, and most recently extensively observed by the NASA/ESA Solar and Heliospheric Observatory (SOHO). The SECCHI telescope suite is returning unprecedented views of the Sun and inner heliosphere. The SECCHI instruments on each of the two STEREO spacecraft observe CMEs from their initiation, through the corona, and into interplanetary space beyond the Earth's orbit. We present an overview of the development and early operations of the SECCHI experiment.

The SECCHI Extreme Ultraviolet Imager (EUVI) is a pair of EUV telescopes on the NASA STEREO mission that was successfully launched in October 2006. The two telescopes, one on each STEREO spacecraft observe the solar corona in three dimensions out to 1.7 solar radii, and with a pixel resolution of 1.59 arcsec. The focus of the EUVI observations is the initiation and early evolution of coronal mass ejections (CMEs). This paper presents a preliminary assessment of the on-orbit performance of the EUVI.

The Heliospheric Imager (HI) is part of the SECCHI suite of instruments on-board the two STEREO observatories launched in October 2006. The two HI instruments provide stereographic image pairs of solar coronal plasma and coronal mass ejections (CME) over a field of view ranging from 13 to 330 R₀. The HI instrument is a combination of two refractive optical systems with a two stage multi-vane baffle system. The key challenge of the instrument design is the rejection of the solar disk light by the front baffle, with total straylight attenuation at the detector level of the order of 10^-13 to 10^-15. Optical systems and baffles were designed and tested to reach the required rejection. This paper presents the pre-flight optical tests performed under vacuum on the two HI flight models in flight temperature conditions. These tests included an end-to-end straylight verification of the front baffle efficiency, a co-alignment and an optical calibration of the optical systems. A comparison of the theoretical predictions of the instrument response and performance with the calibration results is presented. The instrument in-flight photometric and stray light performance are also presented and compared with the expected results.

The Heliospheric Imager (HI) forms part of the SECCHI suite of instruments aboard the two NASA STEREO spacecraft which were launched successfully from Cape Canaveral AFB on 25 Oct 2006 (26 Oct UTC). Following lunar swingby's on 15 Dec and 21 Jan respectively, the two spacecraft were placed in heliocentric orbits at approximately 1 AU - one leading and one lagging the Earth, with each spacecraft separating from the Earth by 22.5° per year. Each HI instrument comprises two wide-angle optical cameras - HI-1 and HI-2 have 20° and 70° fields-of-view which are off-pointed from the Sun direction by 14.0° and 53.7° respectively, with the optical axes pointed towards the ecliptic plane. In this way the cameras will for the first time provide stereographic images of the solar corona, and in particular of Coronal Mass Ejections (CMEs) as they propagate outwards through interplanetary space towards the Earth and beyond. The wide-field coverage of HI enables imaging of solar ejecta from 15 to about 330 solar radii whilst the other SECCHI instruments (2 coronagraphs and an EUV imager) provide coverage from the lower corona out to 15 solar radii. This paper briefly reviews the design and performance requirements for the instrument. The various activation, checkout and calibration activities before and after opening the instrument's protective cover or door (instrument 'first-light') are then described and it is shown that the instrument has met the design requirements, including CCD and camera imaging performance, correction for shutterless operation of the cameras, straylight rejection and thermal requirements. It is demonstrated from observations of a CME event on 24-25 Jan 2007 that the instrument is capable of detecting CMEs at an intensity of 1% of the coronal background. Lessons learnt during the design, development and in-orbit operation of the instrument are discussed.

We report the design, development and performance of the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) CCD camera electronics on NASA's Solar Terrestrial Relations Observatory (STEREO). STEREO consists of two nearly identical space-based observatories; one ahead of Earth in its orbit, the other trailing behind to provide the first-ever stereoscopic (3D) measurements to study the Sun and the nature of its coronal mass ejections. The SECCHI instrument suite consists of five telescopes that will observe the solar corona, and inner heliosphere all the way from the surface of the Sun to the orbit of the Earth, and beyond. Each telescope contains a large-format science-grade CCD; two within the Heliospheric Imager (HI) instrument, and three in a separate instrument package (SCIP) consisting of two coronagraphs and an EUV imager. The CCDs are operated from two Camera Electronics Boxes. Constraints on the size, mass, and power available for the camera electronics required the development of a miniaturised solution employing digital and mixed-signal ASICs, FPGAs, and compact surface-mount construction. Operating more than one CCD from a single box also provides economy on the number of DC-DC converters and interface electronics required. We describe the requirements for the overall design and implementation, and in particular the design and performance of the camera's space-saving mixed-signal CCD video processing ASIC. The performance of the camera is reviewed together with sample images obtained since the STEREO mission was successfully launched on October 25 2006 from Cape Canaveral.

HECOR (HElium CORonagraph) is a coronagraph designed to observe the solar corona at 30.4 nm between 1.2 and 4 solar radii. The instrument is part of the Herschel sounding rocket payload to be flown from White Sands Missile Range in December 2007. Much like for neutral hydrogen, the residual singly ionized helium present in the corona can be detected because it resonantly scatters the intense underlying chromospheric radiation. Combined with the simultaneous measurements of the neutral hydrogen corona made by SCORE, the other coronagraph of the Herschel payload, the HECOR observations will provide novel diagnostics of the solar wind outflow. HECOR is an externally occulted coronagraph of very simple design. It uses a triple-disc external occulting system, a single off axis multilayer coated mirror and a CCD camera. We present measurements of the EUV mirror roughness and reflectivity, tests of the image quality, and measurements of the stray light rejection performance. The mirror uses a novel multilayer design with three components that give HECOR a high throughput.

Surface-brightness responses of the SOHO-LASCO C3 coronagraph and of the Solar Mass Ejection Imager (SMEI) are compared, using measurements of a selection of bright stars that have been observed in both instruments. Seventeen stars are selected that are brighter than 4.5 magnitudes, are not known variables, and do not have a neighboring bright star. Comparing observations of these determines a scaling relationship between surface-brightness measurements from one instrument to those from the other. We discuss units of surface brightness for the two instruments, and estimate a residual uncertainty for the present scaling relationship.

The Solar Mass Ejection Imager (SMEI) instrument consists of three CCD cameras with individual fields of view of 60° × 3° degrees that combined sweep a 160° arc of sky. SMEI covers the entire sky in one spacecraft orbit of 102 minutes. Individual 4-s exposures from each orbit are assembled into full-sky maps. The primary objective in the SMEI data reduction is to isolate the Thomson-scattering signal across the sky from free electrons in the solar wind. One of the steps needed to achieve the required photometric precision is the individual fitting and removal of stars brighter than 6th magnitude from the full-sky maps. The point-spread function of the SMEI optics has several unusual properties. It has a full width of about one degree, is asymmetric, and varies in width depending on where in the field of view the image is formed. Moreover, the orientation of the PSF on the sidereal sky rotates over 360 degree over the course of a year. We describe the procedure used to fit and subtract individual stars from the SMEI full-sky maps. A by-product of this procedure are time series at the orbital time resolution for stars brighter than 6th magnitude. These results are used by Buffington et al. (2007) to calibrate the SMEI instrument against the LASCO C3 coronagraph.

This paper will describe the objectives of the Marshall Space Flight Center (MSFC) Solar Ultraviolet Magnetograph Investigation (SUMI) and the unique optical components that have been developed to meet those objectives. A sounding rocket payload has been developed to test the feasibility of magnetic field measurements in the Sun's transition region. The optics have been optimized for simultaneous measurements of two magnetic sensitive lines formed in the transition region (CIV at 1550 Å and MgII at 2800 Å). This paper will concentrate on the polarization properties SUMI's toroidal varied-line-space (TVLS) gratings and its system level testing as we prepare to launch in the Summer of 2008.

Formation flying opens new perspectives in solar physics, and allow to conceive giant, externally-occulted coronagraphs using a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at a distance of hundred meters. ASPIICS (Association de Satellites Pour l'Imagerie et l'Interferometrie de la Couronne Solaire) is a mission proposed to ESA in the framework of its PROBA-3 demonstration program of formation flying which is presently in phase A. ASPIICS is a single coronagraph which will perform both high spatial resolution imaging of the solar corona as well as 2-dimensional spectroscopy of several emission lines from the coronal base out to 3 R(symbol) using an etalon Fabry-Perot interferometer. The selected lines will allow to address different coronal regions: the forbidden line of FeXIV at 530.285 nm (hot coronal matter), Fe IX/X at 637.4 nm (coronal holes), HeI at 587.6 nm (cold matter). An additional broad spectral channel will image the white light corona so as to derive electron densities. The classical design of an externally-occulted coronagraph is adapted to the formation flying configuration allowing the detection of the very inner corona as close as 0.01 R(symbol) from the solar limb.

White-light Thomson scattering observations from the Solar Mass Ejection Imager (SMEI) have recorded the inner heliospheric response to many CMEs. Some of these are also observed from the LASCO instrumentation and, most recently, the STEREO spacecraft. Here, we detail several CME events in SMEI observations that have also been observed by the LASCO instrumentation and STEREO spacecrafts. We show how SMEI is able to measure CME events from their first observations as close as 20° from the solar disk until they fade away in the SMEI 180° field of view. We employ a 3D reconstruction technique that provides perspective views as observed from Earth, from outward-flowing solar wind. This is accomplished by iteratively fitting the parameters of a kinematic solar wind density model to the SMEI white-light observations and, where possible, including interplanetary scintillation (IPS) velocity data. This 3D modeling technique enables separating the true heliospheric response in SMEI from background noise, and reconstructing the 3D heliospheric structure as a function of time. These reconstructions allow both separation of CME structure from other nearby heliospheric features and a determination of CME mass. Comparisons with LASCO and STEREO images for individual CMEs or portions of them allow a detailed view of changes to the CME shape and mass as they propagate outward.

On 2006 May 24 NOAA's Geostationary Operational Environmental Satellite (GOES) 13 satellite was launched with the next generation Solar X-ray Imager (SXI) aboard. This instrument represents a significant step forward in performance over the previous SXI flown on GOES-12, even before that instrument suffered serious degradation. Like the previous instrument, the new instrument uses a grazing incidence optical design, but with a new detector and other improvements, it has about 10 times the sensitivity, twice the spatial resolution, and greatly reduced wide-angle scattering compared to the GOES-12 SXI. The GOES-13 SXI completed its 6 month checkout period in December 2006. Performance tests included dark current, flat-field, spatial response, scattered light, pointing stability and jitter. We present initial analyses and results of these tests as well as comparisons to ground test results. In addition, GOES-13 solar observations are compared to solar observations by other instruments. When it enters operations, the GOES-13 SXI will provide continuous, real-time observations of the X-ray Sun at 1-minute cadence.

The Solar X-ray Imager (SXI) is a staring grazing incidence X-ray telescope being flown all future GOES Weather satellites. It provides full solar disc images over the spectral range 10Å < λ < 60Å. Optimizing a field-weighted-average measure of resolution for this wide-angle application led to a new non-aplanatic hyperboloid-hyperboloid optical design. A complete systems engineering analysis of the "as-manufactured" telescope mirrors for the SXI telescope is described. This includes image degradation due to diffraction effects, geometrical aberrations (from both residual design errors and manufacturing figure errors), surface scatter effects, all of the miscellaneous errors in the mirror manufacturer's error budget tree, and a rigorous analysis of mosaic detector effects. Four flight models and a spare of the SXI telescope mirrors have been fabricated. The first of these SXI telescopes was launched on the NOAA GOES-13 satellite on May 24, 2006. This presentation first qualitatively illustrates the superb on-orbit performance of the GOES-13 SXI instrument and compares it to the experimental results from the prototype Wolter Type I instrument on GOES-12. Then quantitative information is extracted from the raw on-orbit images to provide experimental validation of the computationally intensive image quality predictions that include both surface scatter effects and detector effects.

NOAA's Geostationary Operational Environmental Satellites (GOES) include instruments focused on both terrestrial weather patterns as well as solar activity. These solar X-ray measurements enable the NWS Space Environment Center to perform operational specification and to forecast Space Weather phenomenon. The disk-integrated solar X-ray flux has been recorded for more than three decades by the GOES X-ray Sensor (XRS). GOES-12 Solar X-ray Imager (SXI) has provided real-time images of the Sun and lower corona since 2003. In October 2004, a sounding rocket underflight was undertaken with the Avalanche X-ray Spectrometer (AXS) to provide reference or "solar truth" spectra and these data are being used to provide absolute calibration for the XRS and SXI instruments. We present a report on the progress of this effort, including results of the data reduction and analysis for the XRS, SXI and AXS. This calibration effort will increase our understanding of SXI and XRS instrument response functions and will improve the accuracy of space weather forecasting.

Solar EUV irradiance plays a critical role in the variability of the upper atmosphere and ionosphere of Earth. Many systems are impacted by these terrestrial changes including radio communication, GPS navigation, and satellite orbits. Monitoring the solar EUV irradiance in the past has been left to research satellites and there have been long periods where gaps in the observational record make it difficult to study and understand the long-term trends and impacts on Earth. The National Oceanic and Atmospheric Administration (NOAA) has, for the first time, included an EUV Sensor (EUVS) on the Geostationary Environmental Operational Satellite (GOES). This EUV Sensor (EUVS), launched in May 2006, is design to provide the solar EUV irradiance information most critical to understanding and modeling Earth's upper atmosphere. The EUVS has five broad EUV channels between 5 and 125 nm. It uses transmission gratings and thin-film filters for wavelength discrimination and silicon diodes for detectors. The EUVS was extensively calibrated at the Brookhaven National Labs Synchrotron Light Source with calibration standards traceable to NIST. It samples the solar irradiance every ten seconds on a continuous basis from geosynchronous orbit. This paper will provide an overview of the EUVS design, calibration, and performance results.

The first of the Geo-stationary Operational Environmental Satellites (GOES) -NO/P series, built by Boeing Satellite Systems was launched on May 24, 2006. The spacecraft, now on-orbit and referred as GOES-13, carries an Earth Imager, Sounder and a collection of space environment monitors (SEM) including, for the first time, a solar Extreme Ultraviolet (EUV) telescope. The five-channel EUV telescope measures the solar EUV energies in five wavelength bands from 5 nm to 135 nm. We analyze the data from the five EUV channels, collected by the Post Launch Telemetry (PLT) tests, and compare it to the predictions of precise optical models of the instrument, using two modeling software- ZEMAXI and FREDII . From our models we detected a misalignment between the SXI and the XRS/EUV bore-sights that were off by approximately 0.25 degree. The reference solar irradiation between 1-140 nm in our model was acquired from the TIMED data taken at the same time as the GOES data. When corrected by the appropriate calibration factors, all 5 channels agreed reasonably well with the TIMED data at zero degree angle of incidence. As expected, the instruments' responses changed by more than 5% as a function of azimuth angles away from the Sun center. These changes in irradiation values as a function of angle could be corrected to the values at normal incidence using photometrical accurate optical models of the EUV instrument.

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 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.

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.

The Solar Dynamics Observatory (SDO) Extreme ultraviolet Spectro-Photometer (ESP), as a part of the Extreme ultraviolet Variability Experiment (EVE) suite of instruments, was calibrated at the National Institute of Standards and Technology (NIST) on the Synchrotron Ultraviolet Radiation Facility (SURF) Beam Line 2 in February 2007. Precise ESP alignment to the SURF beam was achieved through successive scans in X, Y, Pitch and Yaw, using a comparison of the four channels of the ESP quad photodiode as a measure of alignment. The observed alignment between the ESP and the other instruments in the EVE package was found to be in very good agreement with that measured at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado during ESP/EVE integration. The radiometric calibration of the ESP photometers in the spectral range around 4.4 nm (central zeroth order), and the four first order channels centered at about 18.9, 25.4, 29.8, and 36.1 nm was performed with SURF synchrotron radiation. The co-alignment of the SURF beam and the ESP optical axis for each energy and injected current was determined based on quad diode (QD) photometer responses (photodiode count-rate data). This determined beam position was later used to obtain exact energy-wavelength-flux profiles for each of the calibration energies and to calculate the quantum efficiency of the ESP channels. The results of this calibration (quantum efficiencies) are compared to the previous ESP NIST calibration results at SURF Beam Line 9 and to SOHO/SEM efficiencies.

We present a simple EUV spectrometer based on chemically inert rare gas photon ionization and energy analysis of the resulting electrons. Precise photoelectron focusing and high electron transmission efficiency from the gas ionization area to the detector are combined with an optimum luminosity angle of 90 deg in an axi-symmetric design. All together, these features will allow us to achieve higher efficiency and spectral resolution than other spectrometers of this type reported to date. The modeled (neon) spectral resolution in the spectral range of 5 - 40 nm is 0.1 - 0.035 nm, respectively. A model of the proposed photoelectron focusing system is analyzed.

We report the design and laboratory testing of a prototype dual-grating filter-free extreme ultraviolet (EUV) spectrometer that has potential as a highly stable instrument for measuring absolute solar irradiance in the X-ray through far ultraviolet spectral range. The instrument is based on the same freestanding transmission gratings and silicon photodiodes used on the successful Solar EUV Monitor (SEM) aboard SOHO and the EUV Spectrophotometer (ESP) part of the EVE instrument suite to be flown on SDO. Its two gratings, placed in series, along with a simple baffle structure provide excellent out of band "white" light rejection. Because the instrument does not use any thin film filters or reflective optics it is not susceptible to the degradation and instability associated with such optical elements. We present photometric efficiency data from laboratory tests with a Helium and Hydrogen discharge light source and measurements of "white" light rejection taken using the Mt Wilson Observatory 60' solar telescope.

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is being developed to be part of the PROBA2 payload, an ESA technological mission to be launched in early 2008. SWAP is directly derived from the concept of the EIT telescope that we developed in the '90s for the SOHO mission. Several major innovations have been introduced in the design of the instrument in order to be compliant with the requirements of the PROBA2 mini-satellite: compactness with a new of-axis optical design, radiation resistance with a new CMOS-APS detector, a very low power electronics, an athermal opto-mechanical system, optimized onboard compression schemes combined with prioritization of collected data, autonomy with automatic triggering of observation and off-pointing procedures in case of Solar event occurrence, ... All these new features result from the low resource requirements (power, mass, telemetry) of the mini-satellite, but also take advantage of the specificities of a modern technological platform, such as quick pointing agility, new powerful on-board processor, Packetwire interface and autonomous operations. These new enhancements will greatly improve the operations of SWAP as a space weather sentinel from a low Earth orbit while the downlink capabilities are limited. This paper summarizes the conceptual design, the development and the qualification of the instrument, the autonomous operations and the expected performances for science exploitation.

Absolute spectroscopic photocurrent calibration of detectors in the photon energy range of 50-6000 eV is performed at beamlines U3c and X8a of the National Synchrotron Light Source at Brookhaven National Laboratory. These beamlines are specifically designed to provide high flux over a wide energy range, with particular attention paid to harmonic purity of the monochromatic beam. Examples of optics which enhance the beam purity include transmission foils and grazing-incidence mirrors. The AXUV-100G silicon photodiode available from IRD is used as a reference detector. Its relatively simple design, and the availability of x-ray optical data for silicon and silicon dioxide, permit application of the "self-calibration" method of estimating absolute response, typically to 2% accuracy or better. Characteristics of typical such diodes will be described, including spectroscopic responsivity and models, lot matching, electrical characteristics, visible and infrared light responsivity, and soft x-ray photon-induced damage.

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 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 New Solar Telescope (NST) is a 1.6-meter off-axis Gregory-type telescope with an equatorial mount and an open optical support structure. To mitigate the temperature fluctuations along the exposed optical path, the effects of local/dome-related seeing have to be minimized. To accomplish this, NST will be housed in a 5/8-sphere fiberglass dome that is outfitted with 14 active vents evenly spaced around its perimeter. The 14 vents house louvers that open and close independently of one another to regulate and direct the passage of air through the dome. In January 2006, 16 thermal probes were installed throughout the dome and the temperature distribution was measured. The measurements confirmed the existence of a strong thermal gradient on the order of 5° Celsius inside the dome. In December 2006, a second set of temperature measurements were made using different louver configurations. In this study, we present the results of these measurements along with their integration into the thermal control system (ThCS) and the overall telescope control system (TCS).

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 Coudé-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.

The Cassini spacecraft launched in 1997 on a seven year trans-solar system trajectory to reach and orbit Saturn communicates with a circularly polarized carrier signal at multiple frequencies. The transmitted signal includes a very weak component in the opposite polarization (1%). The plane of polarization of this elliptically polarized signal can be used when Cassini is in superior conjunction with the sun to probe the magnetic field of the solar corona through the process known as Faraday rotation. Using a dual circularly polarized receiver, the two components (Left- and Right-Circularly Polarized) were measured during the Cassini superior conjunction in 2002 and analyzed to determine the plane of polarization. The measured plane of polarization was then corrected for leakage between the two circular components in the polarizer. We discuss the methods used for determining the plane of polarization and calibration of the polarizer.

The technique of interplanetary scintillation (IPS) can be used to probe interplanetary space between the Sun and Earth most-commonly in terms of speed and also by using the scintillation-level (g-level) as a proxy for density. We combine the large spatial-scale 3D tomographic techniques previously only applied to IPS data from the Solar Terrestrial Environment Laboratory (STELab) array, Nagoya University in Japan, and the previously operational Cambridge IPS system in England, with the finer-scale capabilities of the longer baselines between the systems of the Multi-Element Radio-Linked Interferometer Network (MERLIN) in the UK, and the European Incoherent SCATter (EISCAT) radar and the EISCAT Svalbard Radar (ESR) in northern Scandinavia. Using the UCSD 3D reconstruction technique, we present results of detailed measurements of speed in the solar wind and also those of solar wind flow-directions, constrained by the large-scale density tomography through the use of a kinematic model, as well as applying this tomographic technique for the first time to the MERLIN, EISCAT, and ESR IPS solar wind speed observations in terms of velocity.

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.

Neutral oxygen (O I) is a dominant species between about 250 and 500 km in the thermosphere. A complete thermospheric model requires measurements of the species density ([O]) to incorporate into forward models. One way to measure [O] is to detect Bowen fluorescence at triplet 844.6 nm. Bowen fluorescence is generated when thermospheric oxygen absorbs Solar Lyman-β and de-excites through a path eventually leading to 844.6 nm emission. This emission must be distinguished from the brighter 844.6 nm emission caused by photoelectron (PE) impact, which can be done by measuring the intensity ratio between two branches of the 844.6 triplet. An instrument to measure Mid-latitude Bowen fluorescence has been installed at Millstone Hill Observatory. The instrument is a Spatial Heterodyne Spectrometer (SHS), a novel type of Fourier transform spectrometer. This SHS was first used to observe Na Fraunhofer lines from dayglow at 589 nm, and is to be turned to the 844.6 region. With simple readjustments, it can also be reset for other visible and near IR wavelengths.