- 1 -

Above: Complex loop structure seen with TRACE in a flaring active region (A. Title). Below: Close up of solar flux tubes penetrating the solar surface seen with the Dunn Solar Telescope and adaptive optics (T. Rimmele).

C PROJECT DESCRIPTION C.1 Overview Understanding the Sun has always been a vital quest of science because the Sun is the most significant astronomical object for humankind. Exciting observations of solar magnetic activity from recent space missions, such as Yohkoh, TRACE and SoHO, have stimulated both scientific and public interest in the Sun. They have highlighted the pervasive role magnetic fields play in determining the nature of the important physical processes driving solar activity and variability. Most importantly, these new observations have put new emphasis on the intrinsic relationship between small-scale physical processes and large-scale phenomena (e.g., coronal mass ejections). Meanwhile, because of improvements in computational capabilities, physical theory and numerical modeling are now addressing the fundamental scales and processes in the highly magnetized and turbulent plasma of the solar atmosphere. Our knowledge has now reached a point where a new solar telescope is needed to make important progress. Now is the time because of a fortunate confluence of new space observations and advanced numerical modeling. Together, these make it necessary to obtain observations of small-scale magnetism in order to understand the basic forces of solar activity. Recent breakthroughs in adaptive optics have eliminated the major technical impediment to making such observations. Even so, the current generation of solar telescopes (dating back to the 1960s) are too small and can neither resolve these small-scale physical processes nor accurately measure the magnetic field. Thus there is no unequivocal observational verification of current models or guidance for future modeling improvements.

This impasse is recognized by the astronomy community, which has advanced strong scientific arguments for a large-aperture solar telescope. The most recent arguments are presented in the latest NSF/NASA Astronomy & Astrophysics Survey Committee (AASC) Decadal Survey (2000) and the NAS/NRC report on �Ground-Based Solar Research: An Assessment and Strategy for the Future� (1999). These reports make a strong and persuasive case for high-resolution studies of the solar atmosphere and the Sun�s magnetic field. The generation of magnetic fields through dynamo processes, the amplification of fields through the interaction with plasma flows, and the dissipation of fields are still poorly understood. There is incomplete insight as to what physical mechanisms are responsible for heating the corona, what causes variations in the radiative output of the Sun, and what mechanisms trigger the flares and coronal mass ejections that affect the Earth, its climate, and its near space environment.

Progress in answering these critical questions requires study of the interaction of the magnetic field and convection with a resolution sufficient to observe scales fundamental to these processes�i.e., the pressure scale height, the photon mean-free path length, and the fundamental magnetic structure size. This proposal presents scientific rationale for a national investment in a new, ground-based, large-aperture solar telescope � the Advanced Technology Solar Telescope (ATST). Such a telescope is required to provide high angular resolution and high sensitivity measurements that cannot be achieved any other way. The broad wavelength coverage (from the visible into the thermal infrared) provided by the proposed ATST also provides a unique capability and will allow observations spanning from the photosphere into the corona.

Development of a 4-m solar telescope presents several challenges not faced by large nighttime telescopes. The enormous flux of energy from the Sun makes thermal control a paramount consideration, both to remove the heat without degrading telescope performance and to control mirror seeing. To achieve diffraction-limited performance, a powerful adaptive optics system is required that operates from the visible to infrared wavelength using solar structure as the wavefront sensing target. Low scattered light is essential for observing the corona but also to accurately measure the physical properties of small structures in, for example, sunspots. Highly efficient contamination control of the primary and secondary mirrors must therefore be addressed. The following major recent achievements in technology and instrumentation now make it possible to realize the ATST. A solar adaptive optics system in the visible and infrared is now in operation at NSO�s Dunn Solar Telescope (DST). The Dutch Open Telescope (DOT) has an open-air design that provides diffraction-limited

- 2 -

Phase-diversity reconstruction of solar photosphere showing bright structures associated with magnetic fields (Paxman, Seldin, Keller)

Simulation of interaction between convection and flux tubes (O. Steiner).

images. The development of high-precision vector polarimeters for the visible (NSO/HAO Advanced Stokes Polarimeter, the Swiss ETH ZIMPOL I and II polarimeters) and the infrared (e.g., NSO Near Infrared Magnetograph), and finally, the availability of large-format, high-speed detectors for the visible and infrared make it possible to do high-resolution imaging and precision spectroscopy and polarimetry over substantial fields of view.

The ATST is a community wide program that will occur in two major phases. This proposal is for the design and development (D&D) phase. The early portion of the design phase will consist of concept development, refinement of science objectives, feasibility and engineering studies that address key technologies, specific conceptual designs for major subsystems, and critical design trade-offs and their effect on science drivers and costs. A concept design review (CoDR) will be held before detailed design work begins. The latter portion of the design phase consists of developing the detailed design and estimating definitive costs. A site survey will be carried out during the D&D phase. A site for the ATST will be selected based on the results of this survey. Dividing the project into a separate design and development phase is a model based on the ALMA (Atacama Large Millimeter Array) project. It permits better cost-control and will provide a more accurate estimate of the construction costs. The D&D phase will cost approximately $12.9M and includes technical trade studies, site selection, both telescope and instrument detailed designs, and a well-costed construction plan. Rigorous project management practices will be applied throughout the project. A critical design review will occur in the fourth year and will be followed by a construction phase proposal. During the second phase, we will construct, integrate, and commission the telescope. The cost of the project, including the design phase, is estimated at $70M. During the D&D phase, we intend to develop national and international partnerships to provide part of the construction cost (see support letters in Section I).

The ATST D&D project is summarized in this project description, which also includes a discussion of the extensive educational outreach opportunities presented by the ATST project. Because of its potential for revolutionizing solar physics, its key role in the suite of solar instruments that will investigate the Sun over the next few decades, and the technical challenges posed by its development, three appendices are included to fully describe the project. Appendix I provides a detailed description of the science objectives and their implication for telescope design. Appendix II is a discussion of the technical effort needed to develop an ATST design, including design trade-off studies and instrument design. Appendix III describes the management plan, organizational structure, and work breakdown. To enhance the flow of the project description, the bibliography in Section D is referenced only in the detailed science write-up in Appendix I as well as the technical description in Appendix II.

C.2 Science Drivers C.2.1 Why Does Solar Physics Need a Large-Aperture Telescope? The solar atmosphere provides an ideal laboratory to study the dynamic interaction of magnetic fields and plasma. Magnetoconvection is a fundamental process that is at the heart of many key problems of solar astronomy and astrophysics in general. For example, understanding the evolution of magnetic flux in the lower atmosphere is essential in addressing the most pressing problems in solar physics, such as the origin of magnetic fields, the irradiance variability, and heating of the corona. Magnetic fields provide channels for energy and momentum transport, thereby closely coupling the dynamics of the upper atmosphere to the convectively driven dynamic behavior of the magnetic field near the surface of the Sun. The photosphere represents a crucial interaction region where energy is easily transformed from one form to another. For example, kinetic energy from convective motion can be easily transformed into magnetic energy. The energy stored in the magnetic field is eventually dissipated at higher layers of the solar atmosphere, sometimes in the form of violent flares and coronal mass ejections (CMEs) that ultimately affect the Earth and drive space weather. The different layers of the solar atmosphere, namely the photosphere, the chromosphere and the corona are connected through the magnetic field and therefore have to be treated as one system, rather than individual

- 3 -

layers. The ATST is a crucial tool needed for trying to understand this complex physical system.

A main driver for a large-aperture solar telescope is the need to spatially resolve the fundamental astrophysical processes at their intrinsic scales in the solar atmosphere. It has long been argued that the fundamental spatial scales are the photon mean-free path and the pressure scale height. To resolve both fundamental length scales in the deepest accessible layers of the solar atmosphere, a resolution of 70 km or 0.1 arcsec is required. However, modern numerical simulations with a resolution of 10 km as well as inference from the best available images have suggested that crucial physical processes (e.g., vortex flows, dissipation of magnetic fields, magnetohydrodynamic (MHD) waves) occur on even smaller scales. Resolving these scales is of utmost importance to be able to test various physical models and thus understand how the physics of the small scales ties into the larger problems. An example is the question of what causes the variations of the solar radiative output, which impacts the terrestrial climate. The Sun�s luminosity increases with solar activity. Since the smallest magnetic elements contribute most to this flux excess, it is of particular importance to study and understand the physical properties of these dynamic structures. Unfortunately, current solar telescopes cannot

even resolve such scales at visible wavelength because of their limited aperture.

To illustrate the current state-of-the-art, Figure 1 shows precision polarimetric observations at the highest, currently achievable resolution using the HAO/NSO Advanced Stokes Polarimeter (ASP) and adaptive optics. Even after deploying the most modern technologies such as adaptive optics, much of the detailed physics remains hidden within the resolution element. The ATST is needed to be able to study these physical processes at the scales at which they occur. Figure 2 illustrates how, in the past, a substantial increase in resolution has helped to improve our physical understanding of solar phenomena. The ATST constitutes a quantum leap not only in terms of spatial resolution, but also in terms of wavelength coverage, of the diagnostic tools available and the capability to perform observations of very high sensitivity.

Figure 1 When observing the magnetic network and internetwork with high polarimetric sensitivity and high spatial resolution, about 10% of the Stokes-V line profiles (circular polarization) show an unusual shape. A "normal" V-profile, probably produced by a single magnetic element, is shown on the top. The other profiles show examples of unusual profiles. These unusual profiles are most likely caused by unresolved magnetic structures with opposite polarity within the resolution element and/or unresolved dynamic events. The ATST will, for the first time, clearly resolve these structures and dynamic events and allow us to compare the observations with numerical simulation. (M. Sigwarth.)

- 4 -

The planned ATST design also permits exploitation of the infrared. The near-infrared spectrum around 1.5 µm has many advantages, particularly for precise measurements of the recently discovered weak, small-scale magnetic fields that cover the entire solar surface and could be the signature of local dynamo action. An aperture of 4 m is needed to clearly resolve these features at 0.1 arcsec in the near infrared. Furthermore, the infrared beyond 1.5 µm provides particularly powerful diagnostics of magnetic field, temperature, and velocity at the upper layers of the solar atmosphere. For example, observations using the CO lines at 4.7 µm have

Figure 2 Illustration of how a significant gain in resolution impacts the observational picture and consequently our physical interpretation of solar phenomena. Above is a continuum image (tick marks in arcseconds) of the primary sunspot in AR7548, 1993.07.23, as obtained with the previous generation of polarimeters, at approximately 6" spatial resolution. The corresponding Stokes polarization spectra (I, Q, and V only) from the indicated pixel (x) are shown. Below, today's spectropolarimeters (the HAO/NSO ASP) produce images and Stokes spectra with 0.5"-1" spatial resolution. A sample of the stokes spectra (Q, and V only) are shown from sub-elements within the box in the same region. The variation in Stokes V, and hence the magnetic structure, over the "pixel" is dramatic; equally dramatic is the gain in physical understanding that results from these observations of higher resolution. Also dramatic will be the additional information gained when, with the ATST, the spatial resolution increases by an additional factor of 5-10, finally providing observations that clearly resolve the solar fine structure and help us understand the important physics behind them. (K. D. Leka.)

- 5 -

Sunspot at very high spatial resolution obtained with NSO Dunn Solar Telescope (T. Rimmele).

already changed significantly our picture of stellar chromospheres and have resulted in a better physical understanding of this important layer in the solar atmosphere. Space missions like Yohkoh, SoHO, and TRACE have advanced our knowledge of the Sun's corona enormously and have renewed interest in diverse coronal plasma problems ranging from how coronal mass ejections are formed and accelerated, to how photospheric magnetic fields drive the inverted coronal temperature structure. These successful space missions have further demonstrated the need for accurate measurements of the coronal magnetic field. The magnetic sensitivity of the IR lines and the dark sky conditions in the IR are important motivation to utilize the ATST for exploring the IR coronal spectrum.

Exploiting the unique diagnostic tools that are now becoming accessible in the IR solar spectrum with newly developed IR detector technology requires the largest possible telescope aperture. The ATST will provide improvement by a factor of nearly three in linear spatial resolution over the largest currently available solar IR facility. This translates into a factor of nearly ten in the ability to discriminate small 2-D cool or hot spots on a diffuse background. This is a level at which new science becomes possible.

The requirement for a large photon collecting area is an equally strong driver toward large aperture as is angular resolution. Observations of the faint corona are inherently photon starved. The fact that in many cases observations of structures and phenomena on the solar disk are also suffering from a lack of photons may be less obvious. The reason is that the solar atmosphere is highly dynamic. Small structures evolve quickly, limiting the time during which the large number of photons required to achieve measurements of high sensitivity can be collected to just a few seconds.

The following sections summarize some of the most pressing science questions that will be addressed with the ATST. A detailed description of the ATST�s science goals is given in Appendix I.

C.2.2 Flux Tubes, the Building Blocks of Stellar Magnetic Fields Observations have established that the photospheric magnetic field is organized in small fibrils or flux tubes. These structures are mostly unresolved by current telescopes. Flux tubes are the most likely channels for transporting energy into the upper atmosphere, which is the source of UV and X-ray radiation from the Sun, which in turn affects the Earth�s atmosphere. Detailed observations of these fundamental building blocks of stellar magnetic fields are crucial for our understanding not only of the activity and heating of the outer atmospheres of late-type stars, but also of other astrophysical situations such as the accretion disks of compact objects, or proto-planetary environments. Current solar telescopes cannot provide the required spectroscopy and polarimetry at an angular resolution to explore the enigmatic flux tube structures.

C.2.3 Magnetic Field Generation and Local Dynamos To understand solar activity and solar variability, we need to understand how magnetic fields are generated and how they are destroyed. The 11-year sunspot cycle and the corresponding 22-year magnetic cycle are still shrouded in mystery. Global dynamo models that attempt to explain large-scale solar magnetic fields are based on mean field theories. Dynamo action of a more turbulent nature in the convection zone may be an essential ingredient to a complete solar dynamo model. Local dynamos may produce the small-scale magnetic flux tubes recently observed to cover the entire Sun. This �magnetic carpet� continually renews itself on a time scale of a few days at most and its flux may be comparable to that in active regions. The ATST will make it possible to directly observe such local dynamo action at the surface of the Sun. The ATST will measure the turbulent vorticity and the diffusion of small-scale magnetic fields and determine how they evolve with the solar cycle.

The ATST will address the following fundamental questions: How do strong fields and weak fields interact? How are both generated? How do they disappear? Does the weak-field component have global importance and what is its significance for the solar cycle?

The ATST will address these fundamental questions by resolving individual magnetic flux tubes and observing their emergence and dynamics. It will measure distribution functions of field strength, field direction and flux

- 6 -

Coronal loop as seen with TRACE (A.Title).

tube sizes and compare these with theoretical models. The ATST will observe plasma motions and relate them to the flux tube dynamics.

C.2.4 Interaction of Magnetic Fields and Mass Flows In sunspots, the total magnetic field is large enough to completely dominate the hydrodynamic behavior of the local gas, a regime very different from that of the rest of the solar photosphere. Numerical simulations and theoretical models predict dynamical phenomena, such as oscillatory convection in the strong-field regions of sunspot umbrae, flows at the speed of sound along penumbral filaments and oscillations and wave phenomena. To verify the predictions of numerical simulations of sunspots and ultimately answer such fundamental questions as �Why do sunspots exist?� require an extremely capable instrument. High-resolution (<0.1 arcsec) vector polarimetry combined with high sensitivity (requires high photon flux) and low-scattering optics are required. Understanding the interaction of magnetic flux and mass flows is crucial for our understanding of the behavior of magnetic fields from the scales of planetary magnetospheres, to star-forming regions, to supernova remnants, to clusters of galaxies. Sunspots allow us to test those theories in a regime where magnetic fields dominate mass flows.

C.2.5 Inhomogeneous Stellar Upper Atmospheres Measurements of CO absorption spectra near 4.7 µm show surprisingly cool clouds that appear to occupy much of the low chromosphere. Only a small fraction of the volume apparently is filled with hot gas, contrary to classical static models that exhibit a sharp temperature rise in those layers. The observed spectra can be explained by a new class of dynamic models of the solar atmosphere. However, the numerical simulations indicate that the temperature structures occur on spatial scales that cannot be resolved with current solar infrared telescopes. A test of the recent models requires a large-aperture solar telescope that provides access to the thermal infrared. Such observations would further explore the dynamical basis of the thermal bifurcation process, a fundamental source of atmospheric inhomogeneities in late-type stars. Spicules, the forest of hot jets that penetrate from the photosphere into the chromosphere, are clearly a MHD phenomenon that is not understood nor adequately modeled. Their role in the mass balance of the atmosphere is uncertain. Combined with UV observations (like those of TRACE), the ATST will allow us to resolve their nature.

C.2.6 Magnetic Fields and Stellar Coronae The origin and heating of the solar corona, and the coronae of late-type stars, are still mysteries. Most of the proposed scenarios are based on dynamic magnetic fields rooted at the 0.1-arcsec scale in the photosphere. However, none of the processes has been clearly identified by observations or theory. EUV and X-ray observations have gained in importance, but ground-based observations are still critical, not only to determine the forcing of the coronal fields by photospheric motions, but also for the measurement of the coronal magnetic field strength itself. This is important for developing and testing models of flares and coronal mass ejections, which propel magnetic field and plasma into inter-planetary space and induce geomagnetic disturbances. In particular, precise measurements of the coronal magnetic field strength and topology are needed in order to distinguish between different theoretical models. The ATST, with its large aperture, low scattered light characteristics, and the capability to exploit the solar infrared spectrum will provide these critical measurements.

C.2.7 Cross-Disciplinary Impacts The processes discussed in the previous sections involve fundamental physics, fluid dynamics, plasma physics, and magnetohydrodynamics (MHD), which are processes that occur throughout the Universe. The Sun provides a unique �laboratory� for studying these key astrophysical processes in detail under astrophysical conditions. For example, such important processes as MHD waves, MHD turbulence, magnetoconvection, magnetic reconnection, and magnetic buoyancy occur in other stars, nebulae, galactic centers, and intergalactic interactions, but can be observed in detail only on the Sun. Solar flares serve as a prototype for many high-

- 7 -

energy phenomena and particle acceleration mechanisms in the Universe. The cause of the Sun's million-degree corona must be understood before we can confidently interpret the EUV and X-ray emission from distant astrophysical objects. Almost all astronomical objects (stellar and galactic) are active, producing intense supra-thermal emissions, both quasi-steady and transient. Detailed observations of small-scale solar magnetic structures will help us understand other astronomical phenomena such as accretion disks of compact objects and proto-planetary environments. The study of solar plasma-magnetic field interaction (magnetoconvection) has the potential of revolutionizing our understanding of solar and stellar structure, stellar activity and mass loss, stellar atmospheres, and how the Sun generates the variability that affects the Earth. Several specific examples are given in Appendix I.

In most cases, our scientific understanding of these solar phenomena is limited by our inability to resolve them at spatial scales less than a few tenths of an arcsecond. Presently no models of solar active regions exist that can produce accurate quantitative predictions of when and where activity will occur on the Sun, or predict what the magnitude of the emissions resulting from that activity will be. The accuracy of solar activity predictions is limited by incomplete understanding of the underlying physical processes in the evolving solar atmosphere. The ATST will provide data needed to develop models for the magnetic evolution of active regions, the triggering of magnetic instabilities, and the origins of atmospheric heating events. These models will provide a much better capability for understanding and predicting when and where activity will occur on the Sun and for predicting the level of enhanced emissions expected from these events. These in turn will permit solar-terrestrial models to be refined to include critical solar data instead of the proxies that are used now.

Outfitted with modern technology, the ATST will provide the necessary sensitivity and spatial and temporal resolution for the next epoch in solar research�the detailed elucidation of the physics of solar and stellar activity and variability.

C.3 The ATST in Context While many areas of solar physics�such as helioseismology, measurements of coronal structure, and studies of small-scale surface dynamics and fields�have grown independently, we now understand that the Sun is a highly coupled system. Physical processes that occur on large and small scales, in the interior and at the surface, interact to produce its complex behavior. It is not possible for a single telescope alone to address the broad range of question that must be answered to understand the Sun. Only by combining the data from many instruments, many time scales, and many spatial dimensions, will true progress be made.

Wavelength

Space

X-ray EUV Visible Near-IR Thermal IRUVGamma-ray0.02”

0.2”

2”

20”

ATST 200”HESSI

Magnetic Energy Domain

2000”

Solar-B

Radio

RotationalEnergy Domain FASR

SOLISSOHO

Solar-B

Convective Energy Domain

SDO

Figure 3 ATST compared to other solar assets.

- 8 -

Primary Mirror

4 meters

Wavelength Range

0.3 to 35 µm

Field of View 5 arc minutes

Diffraction Limited Resolution

0.03 arc sec @ 0.5µ 0.08 arc sec @1.6µ

Low Scattered Light

<10ppm @ λ>1µm , r=1.1rsun

Adaptive Optics

Visible and infrared

Low and stable instrumental Polarization

The Decadal Survey panel report on solar astronomy emphasized the importance of this interplay and the important role the ATST would play. When coupled with high-energy and other observations from space, e.g., SOLAR-B, Solar Dynamics Observatory (SDO), High Energy Solar Spectroscopic Imager (HESSI)), with ground-based radio observations (Very Large Array (VLA), Very Large Baseline Array (VLBA), Frequency-Agile Solar Radio (FASR) Telescope), and with long-term synoptic observations (SOLIS, ISOON, GONG, BBSO, Mees, Marshall), which place the current observations in the context of the solar cycle, the ATST optical/infrared observations will enable a complete picture of the Sun to be developed from its interior to interplanetary space.

Figure 3 shows the complementary nature of the ATST and many of the assets that are available now and that will be available in the future.

C.4 Telescope and Instrument Requirements The final design of the ATST and its first light instruments will be the product of the proposed design and development (D&D) phase, during which a detailed flow down of the design requirements for the telescope and instruments from the science requirements will be performed. The straw man of the basic telescope requirements summarized below and the resulting technical challenges have been determined during several workshops involving large parts of the community. Appendix II provides a more detailed description of the proposed scope and technical approach to the D&D phase. The science requirements also determine the site requirements, which are also discussed in more detail in Appendix II of this proposal.

C.4.1 Resolution The 4-m aperture combined with adaptive optics (AO) will provide diffraction-limited spatial resolution (0.03 arcsec at 500 nm, 0.08 arcsec at 1.6 µm) within the isoplanatic patch, which is of order 10 arcsec in the visible and significantly larger in the infrared. Recent experience with solar adaptive optics systems at Sacramento Peak and at the Canary Islands demonstrates that AO substantially improves the image quality over a much larger field of view (arcminutes) by correcting the near-ground seeing that often dominates the day-time seeing. Sub-arcsecond resolution can be achieved over these much larger fields of view. These data can be further processed using post-facto image processing techniques such as phase diversity to arrive at diffraction-limited observations. In the future Multi-Conjugate Adaptive Optics (MCAO) is likely to �directly� achieve diffraction-limited resolution over field of views of several arcminutes.

Spatial resolution is only one aspect. The science goals require an instrument that enables high-resolution observations in the most general sense. High resolution includes high-spatial, high-temporal, and high-spectral resolution. All three of these are important to our understanding of small-scale phenomena on the Sun.

C.4.2 Photon Flux and Sensitivity Why solar observations are often photon starved: Achieving high spatial, temporal and spectral resolution simultaneously requires a high throughput of photons, which in turn requires a large telescope aperture. The requirement for high throughput is an equally strong driver toward large aperture as is angular resolution. The number of photons per angstrom per second per diffraction-limited angular resolution element is independent of aperture size. Photospheric structures can move or evolve with speeds close to the sound speed of about 6 km/s. So for features 0.1 arcsec or smaller, one must collect photons within a few seconds to avoid spatial smearing. Thus, while a 1-m telescope could, in principle, achieve 0.1-arcsec diffraction-limited resolution in the optical, in practice, a 4-m aperture is necessary to accumulate sufficient photons to allow an accurate measurement of, for example, the vector magnetic field over a time scale in which the dynamic scene does not evolve significantly. Another strong driver for the large telescope aperture are observations of the faint corona.

- 9 -

C.4.3 Polarization Accuracy Accurate measurements of field strength and direction require a telescope with low instrumental polarization. In order to achieve an accuracy of 10-4 in the polarization measurements, instrumental polarization can only be of order 1%. Even at that level any instrumental polarization must be accurately calibrated as a function of telescope pointing.

C.4.4 Low Scattered Light A low scattered light facility is a requirement for the envisioned coronal capabilities of the ATST but also for many other observations. For example, sunspot observations, and in particular observations of the umbra, and umbral and penumbral fine structure, also require instruments with low-scattering optics. Large sunspots with field strength in excess of 3 kG often have residual intensities of less than 10%. In order to accurately measure physical parameters in the umbra, the umbral signal must be at least an order of magnitude above the �noise� introduced by scattered light from the surrounding photosphere. This requires scattered light from the instrumentation to be of order 1% or less. Coronal observations require scattered light to be limited to less than 10-5 of solar disk intensity at 1.1 solar radii and for infrared wavelength.

C.4.5 Wavelength Coverage In order to address the scientific problems stated above, a wide range of diagnostic tools has to be applied. From the beginning, the ATST will be a well-instrumented telescope that allows the combination of different instruments covering a large wavelength range from the UV to the thermal infrared (0.35 � 35 µm). A first complement of ATST instruments will include: • Visible and IR imaging cameras; • Medium- and high-dispersion spectrographs for visible and near-IR; • Thermal-IR spectrograph; • Visible and IR polarimeters; • Narrow-band filter systems. Instrumentation will be designed using a modular approach, which allows use of the same modules to �assemble� different instruments. For example, the same polarimetry package can be used in combination with a spectrograph or a narrow-band imaging filter system.

C.4.6 Field of View In order to allow studies of the evolution of entire active regions, the ATST will provide a field of view (FOV) of 5 arcmin. The quality of the telescope optics will be <0.�1 within this FOV.

C.4.7 Location The best affordable site in terms of seeing, sky clarity and sunshine hours will be chosen in order to maximize the telescope performance and minimize the cost of adaptive optics.

C.5 Summary: ATST Parameters and Example Science Drivers Table 1 presents a flow down from ATST science goals, to observables, to the requirements these place on the telescope design. A more detailed discussion of the science goals that are summarized in Table 1 can be found in Appendix I. One of the early objectives of the D&D phase is to finalize this table. The table also presents telescope and site parameters and the instrumentation needed to achieve the desired capabilities.

C.6 Straw Man Telescope Design Solar physicists have developed many unusual telescopes and instruments specifically for solar observations. To focus the ATST D&D effort, we will begin with a straw man optical layout that draws on previous experience with solar telescopes and recent design studies as mentioned in Section 1 of Appendix II. Table 2 summarizes the basic telescope and performance parameters. Many existing solar telescopes are off-axis designs (e.g., the Dunn Solar Telescope (DST)).

- 10 -

Table 1. Summary Science Objectives and Flow Down to Instrument Requirements

Science Goals Observational Requirements

Telescope Requirements

Telescope and Site Parameters Instruments

Gain Physical Understanding of: • Magnetoconvection • Dynamo processes: � Small-scale dynamo � Origin of weak field and importance for solar cycle • Flux emergence and

dissipation • Formation, destruction,

internal structure of flux tubes/sheets

• Generation of acoustic oscillations

• Chromospheric and coronal heating

• MHD waves • Triggering of activity • Structure of sunspots

• Observe fundamental astrophysical processes at the scales at which they occur

• Measure B and plasma parameters with sufficient spatial and temporal resolution and sufficient accuracy to test theoretical models, e.g., flux tubes

• Observe: visible and

near-infrared spectrum, rich diagnostics

• Spatial resolution: � 0.05� at 500 nm

� 0.1� at 1.6 µm • Large photon flux • Accurate polarimetry (>10-4) • Low scattered light

• Aperture: 4 m • Seeing control:

� Adaptive optics � Thermal control • Low and stable

instrumental polarization < 1%

• Good seeing site

• VIS/NIR spectrographs and polarimeters

• VIS/NIR narrow-band filters

• VIS/NIR Detectors

Gain Physical Understanding of: • Structure and dynamics

of upper atmosphere: � Shock wave heating

� COmosphere � MHD-wave and topo- logical heating � Prominence formation and eruption • 3D-structure of

magnetic field: � Chromospheric and coronal magnetic fields

• Measure B and plasma parameters in upper atmospheric layers

• Observe: � CO lines at 4.8 µm (transition zone from β>1 to β<1, T diagnostics)

� MgI at 12 µm (B, upper photosphere) HeI 1.0830 µm (B, chromosphere) � Coronal lines at e.g., 1.0747 and 3.9µm, (B, corona)

• High resolution • IR access

(>12microns) • Large photon flux • Accurate polarimetry • Low scattered light < 10e-5 at 1.1 solar radii • Coronagraphic

capabilities in IR

• Aperture: 4 m or larger

• Open-air design • Dust Control • Adaptive Optics • Unobscurred light path • Low sky brightness

• NIR/thermal IR detectors

• NIR/Thermal IR spectrograph and polarimeter

Active Region Evolution • Understand process of

activity build-up and triggering

• Dynamo processes

• Measure B and plasma parameters at different layers in atmosphere and over entire active region

• Long time series

• Large FOV (>5 arcmin)

• High resolution over large FOV

• AO & site with large isoplanatic patch or MCAO

• All of the above

• Explore the unknown • New discoveries

• E.g., Explore IR spectrum >12 µm

• Flare spectra in IR

• Flexibility, adaptability

• Multi-observing stations

• Ability to implement new ideas

• All of the above • Users furnished

• Solar/stellar connection • Solar system objects • Astroseismology • Extra-solar planets • Stellar spectroscopy

• Dedicated instrument, long time series of high-resolution stellar spectroscopy

• Coronagraphic observations

• Large dynamic range observations

• High spatial and spectral resolution

• Large dynamic range • Good instrumentation • Low scattered light • Coronagraph

• Largest possible aperture

• Nighttime operations

• High-resolution spectrograph

• Nighttime AO • VIS/IR detectors

- 11 -

The f-ratio of these telescopes, however, is rather long (e.g., DST , f/72) and therefore issues such as heat-stop design become relatively simple. Such long f-ratios, however, are impractical for a 4-m aperture telescope. The concept of a 4-m, fast primary off-axis telescope is an exciting new concept for solar physics. It offers the opportunity to develop an extremely capable telescope that can address all of the scientific problems discussed in the Science section (Appendix I), and promises to revolutionize our understanding of the Sun and stars.

Table 2: Straw Man Telescope Aperture: 4m Optical configuration: Gregorian, off-axis FOV: 5 arcmin Optical Quality: <0.”1 over FOV Adaptive Optics: Strehl >0.5 within isoplanatic patch Wavelength Coverage: 350 nm - 35 microns Polarization Accuracy: Better than 10E-4 of Intensity Coronagraphic: in the IR Scattered Light: <10E-5 at r/rsun = 1.1 and >1µm

During the conceptual design phase of the ATST D&D project, we will identify the specific optical requirements imposed by each scientific goal, prioritize these requirements, determine how well the straw man configuration meets these requirements and develop trade-offs and alternatives as necessary. Some compromises and trade-offs may be necessary. A weighted decision matrix based on the science requirements will be used to select the final optical configuration best suited for ATST.

C.6.1 Design Challenges There are several critical technology areas where a moderate up-front investment will largely reduce the risk involved in developing and using these technologies, aid in selecting the components that will ensure scientific requirements can be met, and/or allow accurate cost estimates. Crucial technologies required for the ATST have recently been developed and successfully demonstrated at existing solar telescopes of smaller aperture (AO, IR, open-air design). Previous initial designs studies (e.g., CLEAR) did not identify any technical show stoppers and with the selected straw man concept, additional work is needed in the following critical areas.

C.6.1.1 Mirror Seeing Most existing solar telescopes avoid image degradation caused by heating of the optical surfaces by placing the optics in an evacuated tube. However, the science drivers for the ATST require an open-air design. Therefore a major design consideration is the thermal control of the primary and secondary optics to ambient temperature in order to avoid mirror seeing. Maintaining the surface of the primary and secondary mirrors at ambient

- 12 -

with AO without AO

Comparison of the images of solar granulation that were taken at 500 nm with the Dunn Solar Telescope shows the improvement offered by AO. The image on the left has been corrected with a low-order AO system. The uncorrected image on the right was obtained simultaneously, but shows part of the same field of view at a slightly higher magnification (T. Rimmele)

Velocities inside a sunspot measured with the AO system at the Dunn Solar Telescope (T. Rimmele)

temperature, despite the roughly 100 W/m2 of energy that they each absorb, is particularly critical for the ATST in avoiding the generation of �seeing,� or image degradation within the telescope�s optical path (Appendix II, Section 3.4).

C.6.1.2 Energy Removal Approximately 12 kW of power must be effectively removed from the input beam at a telescope focus without degrading the telescope�s performance. A heat stop must be designed for the prime focus to remove the tremendous solar heat load. The heat stop is a critical item for a large-aperture, fast solar telescope. A prototype should be developed and tested under realistic conditions (Appendix II, Section 3.7).

C.6.1.3 Adaptive Optics The design of the ATST must include an adaptive optics system that operates from the visible to the thermal infrared wavelengths using solar structure as wavefront sensing target. AO will enable solar astronomers to perform diffraction-limited imaging, and, more importantly, to resolve the fundamental scales in spectroscopic and polarimetric observations of solar fine structure.

NSO has invested substantial resources in demonstrating the first solar AO system that works with solar granulation as the wavefront sensor target. This low-order (24 subaperture Shack Hartmann) AO system achieves diffraction-limited imaging in good seeing conditions. A 4-m class ATST will require a much larger AO system with several hundred degrees of freedom. To minimize the risk involved in the development of large solar AO systems, this development will be performed in steps. In collaboration with the New Jersey Institute of Technology/Big Bear Solar Observatory (BBSO), the Kiepenheuer Institute for Solar Physics (KIS), and the Air Force Research Laboratory (AFRL), an AO system with about 80 subapertures is being developed. A goal is to develop scalable technology that can be utilized for the much larger ATST AO system (Appendix II, Section 7).

AO will be combined with post-facto image reconstruction techniques, such as phase diversity and speckle reconstruction. This combination has already produced stunning imagery of small-scale magnetic elements recorded at the DST.

C.6.1.4 Contamination Control and Scattered Light Accurate, high spatial resolution polarimetry of features such as flux tubes, magnetic pores, and sunspots, as well as pointing off the solar disk to measure coronal magnetic fields, require a low-scattered-light telescope. To meet the relatively stringent scattered-light requirements of the ATST, highly efficient contamination control of the primary and secondary mirrors must be addressed (Appendix II, Section 3.8).

C.6.1.5 Instrumentation Designing an initial set of focal plane instrumentation is an important part of the overall design and development effort. A first step will be to refine the straw man for the initial or �first light� suite of instruments (Appendix II, Section 9.2) in close collaboration with partners and the solar community. There is wide agreement on what some of these instruments will be. For example, visible and near-infrared spectropolarimeters, as well as visible tunable filters, are considered essential instruments. Other instruments, such as an IR fiber spectrograph have to be better defined. The university partners, HAO and NASA collaborators will do much of the instrumentation design work. The partner contributions are described in detail in Appendix III.

C.6.2 Site Selection The choice of a site for the ATST is an important aspect in its design. Although there is no technical challenge involved, the selection of an excellent site for the ATST within a relatively short period of time may influence

- 13 -

schedule, and to some extent cost, of the project. The dominant site requirements are: minimal cloud cover, many continuous hours of sunshine, excellent average seeing and many continuous hours of excellent seeing, good infrared transparency, and if a coronal option is chosen, frequent coronal skies. An ATST site survey working group (SSWG) has been formed to ensure quality site evaluation and selection. This group oversees the ATST siting activities and ultimately recommends a site for the ATST. Members of this committee include experts in the areas of atmospheric seeing, site testing, and infrared and coronal observations from both the US and international community. The committee�s charge includes definition of relevant site test parameters, methods of measuring these parameters, and criteria to be used for site selection. The committee has already presented a straw man of the ATST site test plan (Appendix II, Section 10). This plan will be further refined during the first months of the D&D effort. Because of the time it requires to perform a thorough site test campaign, the instruments needed to carry out the site test measurements should be constructed and deployed as early as possible. NSO has started to conduct an exploratory site-testing program using scintillometers and is currently building a solar differential image motion monitor (S-DIMM), which will be used to determine the seeing parameter r0 at the test sites.

C.6.3 Trade and Design Studies Table 3 summarizes the major trade and design studies that will be performed during the D&D phase. The table captures the main issues that are unique to the ATST development. The items highlighted in bold text indicate the straw man design. A detailed discussion can be found in Appendix II, Section 3.

Table 3: Trade and Design Studies Technical Issue Major Alternatives

Optical configuration On- or off-axis Apalanar or classical type optics Instrument locations F-ratio

Primary and secondary mirror temperature control

Air, liquid, or solid-state cooling Heating of front surface or passive Air-flow across mirror or not

Heat stop Absorbing vs reflective Air or liquid cooling medium

Contamination control Sheath flow over open mirror or overpressure in tube, electrostatic, frequent CO2 cleaning

Coatings Aluminum, protected silver, or multi-layer metallic layer

Adaptive optics Degrees of freedom Location in optical train

Primary and secondary mirror materials ULE, Zerodur, or SiC Guiding and tracking Guiding telescope optically or mechanically coupled to

main telescope Blind pointing

Mount configuration Equatorial, Alt-az or alt-alt-az Enclosure Conventional dome or LEST-type or rolling enclosure

or exoskeleton Polarimetry Various polarization modulating schemes covering the

full wavelength range Post-focus instruments Design first-light instrumentation

“Building blocks” approach Focal locations of instruments Gregorian, Coudé, other Control systems Monolithic or distributed Site selection Test mountain vs lake vs marine environment

- 14 -

C.7 Implementation C.7.1 ATST Development and Management Plan The structure of the ATST project�design and development followed by construction, and integration�is a construct suggested by the NSF/AST, based on their recent experience with the ALMA project. This experience resulted in the conclusion that paper studies alone are not sufficient for a successful design effort and that trade studies and prototyping must accompany design. With trade studies and prototypes, the performance and cost of the facility to be constructed can be realistically assessed. During the fifth fiscal year of the project, the D&D phase will produce the final drawings, leading to a seamless transition to the construction phase of the project. Appendix III gives a detailed discussion of the ATST program and management plans as summarized below.

C.7.2 Design and Development Phase The following program provides a staged development effort for the ATST. Validation of critical technologies, required for design development, to support fiscal planning and to ensure optimum scientific return from the telescope will occur in the first half of the design phase and will take advantage of previous efforts to define large-aperture solar telescopes. The technical issues to be explored are shown in Table 3. NSO has already started exploring a few of these issues and is committed to a substantial investment of its current resources to developing the ATST program.

Formal concept definition will be developed, including definitive trade-off studies, engineering design development, critical risk assessment and mitigation planning, and the development of procurement and management plans. Major components of the D&D phase are the following:

• Formation of the core project team. A full-time team will be established during the first year with the use of contracted assistance for specific design tasks. NSO will house this team and coordinate the various design tasks, many of which will be conducted at the various ATST partner organizations. During the second year, we will ramp up to full staffing for D&D phase procurement and ongoing design and contract management efforts.

• Design development. Specific design studies will be carried out for major subsystems, including optics, structures, facility, adaptive optics, primary focal plane instrumentation and cameras, and controls. NSO will begin technical development of the more complex AO system needed for a 4-m aperture.

• Risk mitigation and cost control development. Development studies and/or experiments on industrial processes and equipment designs, which can result in meaningful mitigation of technical risk and program cost control.

• Conceptual design review. A CoDR will be held early in the second year of the design phase. The review will include results of initial studies, including concept development and analysis, and provide a decision point for design concept selection. It will allow the science advisory committee the opportunity to assess how well the concepts meet the scientific requirements and to redirect the design efforts if necessary.

• Preliminary design review. A PDR will be held during the third year of the design phase. The review will include results of all studies to date, including site testing and selection and design development and analysis. It will provide a decision point for the NSF regarding project status, and will allow the scientific advisory committee an opportunity to assess how well the developed design is meeting the scientific requirements.

• Critical design review. During the fourth year, the design phase will culminate in the presentation of the full ATST design, including instrumentation. A plan for constructing and commissioning the ATST will be presented, as well as an accurate assessment of costs to build and operate the telescope. The CDR will permit NSF and its partners to finalize their commitments for constructing the full-up telescope facility. A successful CDR will result in the submission of a construction phase proposal to the NSF/MRE (Major Research Equipment) program.

- 15 -

• Production of manufacturing and construction drawings. During the fifth year, manufacturing and construction drawings will be completed to ensure a seamless transition to the construction phase once the funding decisions are made.

C.7.3 Summary of D&D Phase Deliverables The main deliverable of the ATST design and development phase is a construction proposal that includes the following:

• A fully developed science requirements document. • Functional performance requirements documents with traceable flow down of requirements from

science to technical. • Detailed telescope design documents, including final drawings. • Detailed instrument design documents. • Interface control documents. • System error budget. • Quotations for major construction subcontracts. • Management plan for construction. • Configuration management plan. • Integrated plan/management process for software acquisition. • Hardware and software compatibility standards. • Acquisition plan and procedures. • Plan for operations. • Scientific data management plan.

The schedule for the high level tasks is shown in Table 4. A complete work break down structure has been developed and is available on the WWW at http:/www.sunspot.noao.edu/ATST/. A more detailed discussion of the tasks is given in Appendix III. C.7.4 Management Plan The ATST is envisioned as a joint effort between the NSO, US universities, and foreign partners. US universities will be deeply involved from the outset. An ATST Advisory Committee has been formed and the current members are:

Thomas R. Ayres University of Colorado Philip R. Goode New Jersey Institute of Technology and Big Bear Solar Observatory Michael T. F. Knölker High Altitude Observatory Jeffrey R. Kuhn University of Hawaii Robert Rosner University of Chicago John H. Thomas University of Rochester Alan M. Title Lockheed Martin/Palo Alto Research Labs

The primary roles of this committee is to advise the NSO Director and help him develop national and international partnerships for the entire ATST project, to galvanize the solar community in support of the ATST, and to develop support in the broader astrophysical and physics communities.

One of the first and most important tasks to be performed during the initial D&D phase is to refine and prioritize the science drivers and develop the science requirements document. This task will be carried out by the ATST Science Advisory Committee (ASAC) and its sub-committees which will address specific issues, e.g., coronal science requirements, site survey, instrumentation. The ASAC will be formed from a subset of the collaborators and co-PIs and will be augmented by international scientists who can contribute to the telescope design.

NSO will take on overall project responsibilities, with university groups assuming responsibility for particular design and instrument work packages. The management structure will evolve to coincide with the project

- 16 -

phases. The initial organizational structure for the design effort is shown in Figure 4. Table 5 summarizes those tasks that will involve sub-awards to and teaming between the various partners.

Table 4. Schedule for High-Level Tasks and Reviews

Task Name FY01 FY02 FY03 FY04 FY05

Start D&D Phase

Recruit Project Team

Science Requirements & FPRD

Conceptual Design

Concept Design Review

Preliminary Design

Technical and Trade Studies

Site Testing

Site Test Deployment

Site Selections

Preliminary Design Contracts

Preliminary Design Review

High-Order Adaptive Optics

Focal Plane Instrumentation

Final Design

Final Design Contracts

Prepare Construction Phase Proposal

Critical Design Review

Submit Construction Phase Proposal

Implement Recommendations of CDR

D&D Phase completed A project systems engineer and program manager will be appointed at the beginning of the D&D effort. Potential candidates exist within the current AURA staff and partner groups. Some of the key scientific personnel for the early phases of the project are discussed below.

Dr. Stephen Keil will be responsible for the overall operation of the project as principal investigator. Before joining NSO, Dr. Keil was principal investigator on the DoD/NASA Solar Mass Ejection Imager (SMEI), which is now nearing completion and will be launched in early 2002. Dr. Keil also managed the DoD Advanced Solar Activity Modeling project and was chief of the solar research branch for 16 years.

Dr. Thomas Rimmele will be the project scientist with overall responsibility and authority for conducting the D&D effort. Dr. Rimmele was the PI on the successful NSO projects to develop low-order adaptive optics, correlation trackers, narrowband filters in the visible, and high-speed, large-format CCDs.

- 17 -

Dr. Christoph Keller will be an associate project scientist with responsibility in the areas of telescope and instrumentation design. Dr. Keller is project scientist for the SOLIS spectral vector magnetograph and he has helped developed numerous instruments including the ZIMPOL polarimeters.

Dr. Frank Hill will be associate project scientist for site selection. Dr. Hill has had extensive experience running the highly successful GONG site selection program. Mr. John Briggs of the University of Chicago will serve as project engineer for the site testing instruments.

Drs. Jeff Kuhn and Haosheng Lin from the University of Hawaii will take responsibility for the definition of coronagraphic aspects of the ATST. Drs. Kuhn and Lin have a long-standing interest in coronal sciences and are currently carrying out the SOLAR-C coronagraph project.

Dr. Michael Knölker of HAO, Drs. Robert Rosner and Fausto Cattaneo of the University of Chicago, Dr. John Thomas of the University of Rochester, Dr. Robert Stein of Michigan State University, Dr. Paul Bellan of the California Institute of Technology, and Dr. Aad van Ballegooijen of the Harvard-Smithsonian Center for Astrophysics will have responsibility for ensuring that theoretical and modeling needs are being met by the developing ATST design.

Mr. David Elmore and Mr. Kim Streander of HAO have responsibility for development of the visible light spectropolarimeter design at HAO. In addition, they will have responsibility for the site survey operations at Mauna Loa and the coronal calibration of the site survey.

Associate Project ScientistSite Testing

Project Manager

Systems Engineer Administrative Assistant

Contract Administrator

Systems Administrator

Technical WriterControls Group

ATST Workshops

Instrumentation

AO Systems Engineer

NSF

NSO Director

AURA

ATST Project ScientistScience Advisory Committee

ATST Advisory Committee

Instrument Scientists

Associate Project ScientistOptics

Associate Project ScientistAdaptive Oprics

Associate Project ScientistTelescope

Optics Group

Telescope, Site,Building& Enclosure Group

Figure 4 Organizational Structure

- 18 -

Dr. Philip Goode of the New Jersey Institute of Technology/Big Bear Solar Observatory will have responsibility for IR instrument development at NJIT/BBSO and for site survey operations at BBSO. He also serves as co-PI on the development of the adaptive optics system.

Table 5. Task and Teaming Task Institutions

Site-Testing Instrumentation NSO University of Chicago HAO

Optical Alignment of Off-Axis Telescope, Contamination Control, Scattered Light

University of Hawaii, Institute for Astronomy (IfA) UCSD NSO

Visible Spectro-Polarimeter Design, Visible/Near-IR High-Dispersion Spectrograph Design

HAO UCLA NSO

Near-IR Polarimeter Design University of Hawaii, IfA California State University, Northridge NASA/Goddard Space Flight Center

Visible Tunable Filter Design NASA/Marshall Space Flight Center NSO Lockheed Martin, Palo Alto Research Labs

Near-IR Tunable Filter Design New Jersey Institute of Technology NSO

Thermal-IR Fiber Spectrograph University of Hawaii HAO

Modeling Princeton University University of Rochester University of Chicago HAO Montana State University Michigan State University Stanford University

C.7.5 Partnerships In addition to the NSF-supported collaborators described in this proposal, NSO will seek partners that can make strong fiscal contributions to the ATST construction phase. Establishing partnerships in the telescope project with foreign countries as well as US agencies other than the NSF is among the goals of the ATST D&D phase. Partners in the project will be included in the intellectual and financial definition of the ATST design and site selection as well as construction. This proposal contains statements of interest from several potential partners.

Progress in securing partnerships for the ATST, as indeed progress in realizing the technology to achieve the capabilities desired of the ATST itself, begins with the efforts outlined in this D&D proposal. Examples of this progress are already evident. NSO, the New Jersey Institute of Technology/Big Bear Solar Observatory, the US Air Force, and the Kiepenheuer Institute for Solar Physics have formed a partnership to develop high-order solar adaptive optics. Their collaborative effort to construct three AO systems provides a model of how domestic and international partnerships can work in building the ATST. The AO team fuses the expertise of four institutions while sharing the cost, which in the end is more cost effective than building a single system.

- 19 -

Key milestones in the development of partnerships include:

• Jun 2000 Contacting international and non-NSF-funded groups with potential interest. • Apr 2001 Determining level of participation and tasks to be performed by individual groups in the D&D Phase. • Nov 2001 Establishing MOU�s with participating groups. • July 2003 Developing funding agreements for the construction phase.

C.8 Educational and Public Outreach C.8.1 The ATST Role in Education The ATST consortium will provide education and outreach (EO) on several fronts that leverage and expand existing programs within the partnering groups and create unique opportunities offered by the ATST during both its development and operation. The involvement of universities with large minority populations, the current location of NSO in regions with substantial Hispanic and native American populations, and the geographic separation of the partnering institutions will permit us to address both ethnic and geographic diversity issues. The consortium is strongly committed to the recruitment of women and minorities in astronomy. An Educational and Outreach officer will be appointed to coordinate the efforts of the ATST partnering organizations.

The goals of the ATST EO program are:

• To increase student, teacher, and public understanding of the Sun, both as a star and as the driver of conditions on the Earth;

• To foster and sustain the growth of a newer generation of solar physics research.

• To increase, nationally, the strength and breadth of the university community pursuing solar physics.

• To enhance the understanding and application of science and math education in our schools, colleges and the public at large.

Strategies for accomplishing these goals are several fold. We will develop a spectrum of EO programs not only in solar physics, but which transcend several disciplines. These include space and laboratory plasma physics, solar-terrestrial physics and solar impacts on space weather, magnetohydrodynamics in both stellar and cosmological astrophysics, mathematical modeling, and advanced instrumentation such as adaptive optics. The EO program will draw from and reach out to a broad community including the public at large, high school students, teachers drawn from K-12 and college community programs, undergraduate and graduate students, postdoctoral and staff researchers and university staff. It will encompass a range of activities that include lectures and demonstrations, research, exhibits, science and math curricula, and web-based learning. We will build on successful programs at the national centers and participating universities at all levels of education.

C.8.2 Overall Program C.8.2.1 Higher Education Undergraduate Education: The science and technological aspects of ATST offer a unique opportunity to greatly increase the role of solar physics in undergraduate education. During the D&D phase, we will develop educational modules designed to take advantage of the new observations and insights that will derive from use of the ATST. We will develop a plan for integrating these into existing astronomy and physics curricula that can be implemented as the ATST becomes operational.

ATST Graduate and Masters Thesis Fellowships: Several graduate student positions will be established at the partnering universities. Thesis topics will range from innovative mechanical, electrical and optical engineering techniques, AO, spectroscopic and polarimetric instrumentation, IR and optical imaging techniques, development of filter systems, observational studies exploiting AO and IR techniques at existing

- 20 -

telescopes, and theoretical studies of fine-scale solar magnetic fields and their interactions with the turbulent solar plasma.

Postdoctoral Opportunities: During the D&D phase, the ATST will provide opportunities for observational, theoretical and instrumental postdoctoral positions. Postdoctoral candidates will be hired to participate in instrumentation and analysis of site survey data, and modeling and simulation efforts related to science and engineering goals and instrument development. C.8.2.2 K–12 Education Currently, the partner organizations participate in a wide range of programs to enhance science education in grades K�12. The participation occurs through formal programs and informal commitments of staff members to local education. Modules on modern solar telescopes, solar observing techniques, and properties of the Sun, using the ATST and its capabilities as an example, will be developed in workshops, bringing teachers and researchers together through several of the programs discussed in Section C.8.3. These modules will then be disseminated to classrooms throughout the country through existing outreach programs in which the ATST partners participate.

C.8.2.3 Public Outreach The ATST partners participate in a variety of public outreach programs through visitor centers, educational WWW sites, consortium for producing and distributing outreach material, and individual efforts. Modules explaining the ATST science program and development of the telescope will be developed and distributed through these outlets.

C.8.3 Existing and Planned Educational Programs The ATST offers significant opportunity to enhance and coordinate the EO activities at the various partnering institutions, both leveraging existing programs and introducing new efforts. Below, we discuss some of the activities that will be undertaken at the partnering institutions as part of their participation in the ATST effort. Their letters of commitment and support in Section I provide further information. As the project progresses, other partnering institutions will involve students in their programs and ATST educational materials in their K-12 outreach programs.

Once the EO coordinator is in place, we will expand on the collaborative aspects of the program. In particular, our partnerships with the two NASA centers will allow us to link ATST related modules and eventually data at the extensive NASA outreach sites. ATST materials will also be closely tied into the developing Virtual Solar Observatory effort, which is a community wide program to tie to gather solar data sites.

C.8.3.1 National Solar Observatory NSO conducts annual programs offering both graduate and NSF REU (Research Experience for Undergraduates) students the opportunity to participate in astronomical research programs. A large fraction of active solar astronomers have participated in the program. Each summer 8-12 undergraduate and 3-4 graduate students participate. Women make up 45% of the participants. Students will be recruited into these programs specifically to work on ATST related science projects and to participate in instrument development programs.

ATST science and technology will be incorporated into classroom material that NSO produces and distributes nationally through participation in the Astronomical Society of the Pacific Project ASTRO. NSO personnel participate as mentors and instructors in the NSF Research Based Science Education (RBSE) program and the NSF Research Experiences for Teachers (RET) program. Through these programs, high school teachers will work with NSO staff scientists to develop classroom exercises based on ATST developments and related NSO data that are available on the WWW. Staff members mentor high school students in local challenge programs in Alamogordo and Cloudcroft, NM school districts and in several school districts in Tucson, AZ. NSO staff also provide lessons and demonstrations at the Tohono O�Odham Reservation schools in Arizona.

NSO has several growing public outreach programs and the scientific and technical excitement generated by the ATST will greatly enhance their impact. NSO is a strong participant in the Southwest Consortium of Observatories for Public Education (SCOPE). SCOPE is a consortium of research institutions in the southwest that promotes public awareness of astronomy through access and education. This valuable collaboration results

- 21 -

in excellent interaction among the public and educational outreach staff of these groups and includes cooperative promotion, visitor center display sharing, and the ability to leverage limited funding into additional outreach opportunities. We will produce materials that reflect the new capabilities of the ATST to describe solar astronomy and the effects of the Sun on the Earth for dissemination by SCOPE.

The NSO Astronomy and Visitor Center at Sacramento Peak is host to over 50,000 visitors per year. A wide range of interactive education displays at the Visitor Center will incorporate ATST development and science exhibits. These displays provide hands-on experience with astronomical and terrestrial phenomena, interactive demonstrations on the properties of light and how telescopes work, recent science results from both ground-based and space-based solar and astrophysical experiments, and access to interactive Web-based pages.

The NSO WWW site contains several public outreach areas including a digital data library, live solar images, and virtual observatory tours. During development of the ATST, we will maintain detailed descriptions of its objectives and progress. These will be highlighted with ongoing results from our existing telescopes as ATST technologies are developed and tested.

C.8.3.2 Programs at the High Altitude Observatory (HAO) HAO�s long-standing programs for educating and training young scientists and its contributions to K-12 educational outreach and public information through other University Corporation for Atmospheric Research (UCAR) programs can be adapted easily to mount effective ATST educational initiatives. HAO�s contributions to the ATST EO program will include the following activities: • Appointment of an HAO Newkirk Fellow to undertake research for up to three years to complete a

dissertation and earn the PhD and serve as HAO scientific liaison with scientific and educational societies in support of the ATST educational initiatives.

• Support of two undergraduate appointments for four summers to enable four to eight students to engage in scientific research guided by experienced scientists working in fields related to the ATST program. These appointments could be made through the NSF-sponsored UCAR SOARS program (Significant Opportunities in Atmospheric Research and Science).

• Expansion of the �Windows on the Universe� Web site, which provides attractive education and public information, to support the ATST educational initiatives. Sponsorship of a national teacher workshop each summer for four years to strengthen K�12 science education.

C.8.3.3 New Jersey Institute of Technology (NJIT) NJIT will involve several graduate students in the development of adaptive optics (AO) and near-IR filters and polarimeters for the ATST and existing solar telescopes at Big Bear Solar Observatory (BBSO). Students will receive PhDs from NJIT in various fields, ranging from applied physics to electrical and computer engineering to computer science. BBSO will also support 2�3 undergraduate students for summer research related to the ATST.

The NSF/Major Research Instrumentation (MRI) program has recently funded NJIT to build, with NSO and the Kiepenheuer Institute for Solar Physics (KIS), three adaptive optics systems�one for BBSO, one for NSO, and one for KIS. This project will be a strong draw for talented NJIT students and offers the opportunity to draw students from minority groups. NJIT envisions three students performing PhD work on the AO project. The students would divide their time between BBSO, NSO, and the laboratories at NJIT. Such training will prepare the students for a scientific career, while ensuring broader career opportunities. After the completion of the AO development effort, scientists and observers will be trained in the use of AO and the reduction of AO data at NSO and BBSO and will be valuable contributors to development of AO for the ATST.

C.8.3.4 California State University at Northridge (CSUN) CSUN, a designated minority-serving undergraduate institute, owns and operates the San Fernando Observatory (SFO), which specializes in synoptic full disk observations and magnetic field measurements of active regions. New initiatives at SFO include installation of a tip-tilt correction system, a new infrared program based around a HgCdTe array, and a theory program aimed at investigating the scaling dynamics of the solar magnetic field.

- 22 -

With a long history of teaching undergraduates, the CSUN Physics Department is developing new courses, targeted at giving undergraduates lab experience with CCDs, spectroscopy and infrared cameras, with an emphasis on solar physics applications at the SFO. We are interested in condensing these full semester courses into a summer workshop designed to train high school teachers from around the country.

Several teacher-training programs currently operating at CSUN, including Project SUN (Students Understanding Nature), will be used as models for this effort. In conjunction with the ATST, CSUN will work closely with NSO, HAO and other partner universities to enhance the undergraduate and K�12 teacher involvement in the ATST project through undergraduate research and laboratory courses at CSUN, teacher training programs, and Web-based outreach.

C.8.3.5 Programs at the University of Hawaii The University of Hawaii, with its strong emphasis in experimental and observational astrophysics, has helped train many of the solar physicists now active in research and teaching. The Haleakala Observatory and the Mees Solar Observatory have been important �magnets� for drawing the next generation of teachers and researchers into solar physics. This facility is an integral part of the Institute for Astronomy (IfA) and its educational mission. The IfA continues to expand its role in teaching and outreach, which now includes the largest teacher education/enrichment program supported by NASA (the Pacific Rim "TOPS" mission) and a well subscribed Research Experience for Undergraduates (REU) program. The IfA's managing and research association with the worlds largest observatory (Mauna Kea) gives it a critical mass of shared expertise in an extremely diverse range of educational and research activities. The University of Hawaii will involve graduate students in trade studies that look at the properties of an off-axis telescope design, in development and testing of SOLAR-C where many of the concepts planned for the ATST will be tested.

C.8.3.6 The University of Chicago ATST participants at the University of Chicago bring a strong interdisciplinary component to the ATST outreach program. They supervise students in physics, mathematics and computer science, and astronomy and astrophysics. They plan to have several graduate students working on theoretical modeling of solar convection in the presence of magnetic fields and magnetic diffusion. The Astronomy and Astrophysics Department has a strong WWW-based program for outreach in Astronomy that will incorporate ATST material.

C.8.3.7 Programs at the Montana State University (MSU) The MSU solar physics group is engaged in undergraduate and graduate education, public outreach, and in solar research supported by NASA, NSF, and Air Force Office of Scientific Research (AFOSR). Research at MSU includes observation, data analysis, theory, and instrument development, which all involve student participation. MSU is actively involved in the Yohkoh Public Outreach Project (YPOP). This project, which is funded by NASA, includes high quality public access to the Yohkoh/SXT data and other solar data via the Internet and educational products for the K-12 community. These products utilize modern technology and include interactive lessons geared at increasing public awareness of science, with a strong emphasis on astronomy and the space sciences. Tools developed for YPOP will be utilized to construct outreach programs based on ATST data. In the near-term, MSU plans to involve students in ATST site survey and instrumentation testing efforts. MSU future plans include extensive use of high-resolution ATST observations after the telescope becomes available, and training students for ground-based observations.

C.8.3.8 University of Rochester Graduate students at the University of Rochester will be involved in high-resolution solar observations with existing solar telescopes that push the current state-of-the-art and provide information that will help refine ATST science goals. The university will also have students involved in the development of improved theoretical models of dynamical phenomena associated with sunspots. They will develop appropriate observational tests of these theoretical models and the corresponding instrumental requirements for these tests.

C.8.3.9 California Institute of Technology (Caltech) Caltech will provide undergraduate and graduate students the opportunity to work on plasma physics experiments related to solar activity. In particular, experiments on magnetic helicity and magnetic relaxation

- 23 -

directly related to the observations expected from the ATST will provide students with exposure to forefront solar physics problems. Caltech will also support theoretic thesis projects related to magnetic instabilities on the Sun.

C.8.3.10 UCSD UCSD has several programs that will incorporate ATST material. The UCSD staff members participate as mentors in the California Alliance for Minority Participation (CAMP) in science and mathematics. They also develop and provide material for the UCSD Charter Schools that work with underprivileged students in K-12 grades involved in projects at UCSD. ATST material will be incorporated into the CASS WWW outreach pages and television programs produced for the Fleet Theater Planetarium.

C.8.3.11 The University of Colorado The University of Colorado at Boulder has a long and continuing tradition of very active involvement in solar physics research and teaching, primarily within the Department of Astrophysical and Planetary Sciences (APS) and its associated research centers JILA, CASA and LASP. APS teaches several thousand undergraduate students the joys of general astronomy each year, and has vigorous REU efforts in which solar physics also has an important role. APS has close ties with HAO and NCAR, both in collaborative research and in teaching. A number of HAO staff have adjunct teaching positions, and many graduate students have carried out their thesis research at HAO. The current theoretical research emphasis in APS complements the ATST programs very well, dealing with simulations and theory of compressible turbulent magnetoconvection, magnetic dynamo processes both on local and global scales, magnetic flux structures � their instabilities and evolution, solar differential rotation, tachocline and near-surface shearing layers, solar atmospheric structure as revealed by UV, optical, and IR spectroscopy, and variations in the Sun�s radiative output. There is active participation of faculty and graduate students in observational programs, including use of NSO facilities (GONG, Dunn VT, McMath IR) and with spacecraft such as SoHO, TRACE, and the SOLSTICE solar irradiance monitor on UARS. A hallmark of many doctoral thesis research programs has been the close interplay between solar observations and theory; thus ATST will provide novel, innovative research choices for students dealing with the highly nonlinear dynamics of the solar convection zone and its adjacent atmosphere.

C.8.3.12 Other Planned Programs UCLA will involve graduate students in designing an IR spectrograph for the ATST. The UCLA IR laboratory has an excellent record of involving students in instrument development projects. Michigan State University involves both graduate and undergraduate students in its current solar programs with efforts centering on theoretical modeling of solar convection and solar-stellar connection. Stanford plans to involve graduate students of the Stanford Physics Department in ATST research. In particular, students will help in developing models and methods for studying excitation of solar oscillations, magnetic and hydrodynamic effects of solar flares, and magnetic structures and mass flows beneath the surface. Stanford will also incorporate ATST educational materials into their excellent solar outreach WWW site for K-12 and the public.

C.8.4 Increasing Diversity The institutions represented in the ATST collaboration cover a wide geographic area, from the eastern seaboard to Hawaii. Several universities that have large minority enrollment are members including the University of Hawaii, California State University Northridge and the New Jersey Institute of Technology. The ATST project will actively recruit and incorporate students from very diverse backgrounds into the program. The K-12 outreach programs at NSO, which include classroom participation, mentoring, teacher workshops and observatory visits, reaches a diverse Hispanic and native American population in New Mexico and Arizona.

C.8.5 Schedule and Plans Recruitment of graduate students and postdoctoral fellows will begin during the first year of the D&D phase and continue throughout the program. An education and outreach (EO) program coordinator will also be hired during the first year to coordinate programs of the various partner institutions, to monitor the progress and success of the overall program, to develop displays for the visitor centers located at the various partner institutions, and to develop ATST related packages for the WWW outreach sites and the classroom. The EO program coordinator will be responsible for disseminating among the partner institutions materials and courses

- 24 -

developed by those institutions and for making this material available to other schools and universities. During the third and fourth years of the D&D phase, a continuing outreach program based on data from the ATST and integrating ATST data with other ground and space instruments will be developed for inclusion in the construction and operational phases of the ATST program.

C.9 Results from Prior NSF support Members of the ATST consortium have had a broad impact on solar research and instrumentation. Both NSO and HAO receive their funding through cooperative agreements between the NSF and AURA and the NSF and UCAR, respectively. Most work at both institutions is NSF-funded and is not covered under independent project proposals. However there are exceptions to this, such as the recently funded NSF/MRI adaptive optics proposal submitted by NJIT/BBSO, NSO, and KIS. In this case, NSO will conduct much of the work in collaboration with NJIT/BBSO and KIS.

We discuss results from several NSO and HAO projects that were funded during the last five years, primarily by NSF, although some funds from the USAF and NASA were also used. We will then highlight recent NSF projects at the three university co-PI�s institutions.

C.9.1 NSO Adaptive Optics � The development of a solar adaptive optics system has a long R&D history. AO during the daytime presents several challenges not faced by nighttime systems. The NSO low-order AO system finally demonstrates the feasibility of solar AO. The NSO adaptive optics system is now used routinely at the DST to obtain high-resolution observations of solar fine structure. These observing runs have provided several users of the DST with data of unprecedented quality. Examples can be viewed at www.sunspot.noao.edu/AOWEB. Following a request by the Kiepenheuer Institute, the NSO AO system was shipped to the Canary Islands (Tenerife), where it was successfully operated at the German VTT. Data supporting two PhD theses were generated. The New Jersey Institute of Technology/Big Bear Solar Observatory has asked to perform a similar campaign at their telescope.

SOLIS � This $6M NSF-funded program is approximately 60% complete. SOLIS (Synoptic Optical Long-term Investigations of the Sun) is a project to obtain daily, high-precision, optical measurements of processes on the Sun whose study requires well-calibrated, sustained observations over a long time period. The major scientific result of SOLIS will be an improved understanding of how and why stars like the Sun produce activity, and how this activity affects human endeavors. SOLIS has developed some new techniques and technologies in the areas of fast optical systems, thermal control, data handling that will prove to be useful to the NSO Advanced Technology Solar Telescope project. E.g., the expected 2.3 TB of daily raw data will be processed by state-of-the-art data handling systems and planned improvements to NSO�s digital archive will allow reduced results to be promptly available over the Internet. Off-site users will be able to schedule particular observations to support their research and educational programs. SOLIS will commence operations during FY 2002, after a four-year design and construction period. The operational life of SOLIS is 25 years.

RISE/PSPT � This proposal was submitted to NSF under the Radiative Inputs from the Sun to the Earth program. The PSPT is jointly funded by the MPS/AST and GEO/ATM divisions of the NSF at the level of $1.2M. NSO built three telescopes for doing high-precision photometry of features on the solar surface. The first was sent to the University of Rome for operation in Italy, the second to HAO for operation on Mauna Loa, and the third is being operated at Sunspot, NM. All three telescopes have performed extremely well and the data are being collected, reduced and archived at the RISE data center at HAO. All data are publicly available through the WWW. The project goal is to determine the cause of variations in the solar radiative output that affect the Earth�s climate. The PSPT was built for less than the estimated cost. The PSPT instrument will be operated for at least a full solar cycle to provide complete photometric coverage of all the phases of the solar cycle.

Digital Library � The NSO solar archive and digital library has become a valuable tool for researchers. It provides easy and quick access to both past and current data. NSO will add past film archives to the archives as resources allow. The synoptic data sets have a wide range of users, from those needing contextual data for their own experiment, to those trying to understand the impact of solar emissions on terrestrial, interplanetary

- 25 -

and space weather models. We are currently getting approximately 28,000 hits per year on the WWW database. Because our data are also disseminated through the NGDC archives in Boulder and through the Solar Geophysical Data Journal issued by NOAA, our statistics probably represent only a fraction of the users of our synoptic observations. Funding for development of the digital library came from both the NSF and NASA. Total cost was$200K.

GONG � GONG is an ongoing, NSF-funded project, whose annual operating budget is approximately $1.9M. The Global Oscillation Network Group (GONG) is a community-based, international project studying the internal structure and dynamics of the Sun by measuring resonating waves that permeate the solar interior � a technique known as helioseismology. GONG has been operating a network of six solar velocity mappers located around the Earth, to overcome the limitations imposed by the day-night cycle at a single observatory, since October 1995 obtaining nearly continuous observations of the "five-minute" oscillations. The initial GONG observations have yielded significant results on everything from the temporal variation of the gravitational constant (G) to the nature of rotational shear at the base of the convection zone. They have also demonstrated very clear, solar-cycle related variations of the internal structure of the Sun, and operating GONG for a full solar cycle should yield important new insights on the fundamental physical processes that control solar variability

GONG+ - In order to enable continuous local helioseismology (which probes structures such as convection cells or hidden active regions inside or on the backside of the Sun), and to probe closer to the visible surface, GONG is replacing the existing 256 × 256-pixel cameras with 1024 × 1024 ones that will support the systematic study of the variation of the solar interior over the solar cycle, and provide continuous surface velocity and magnetic field measurements as well.

Other Instrumentation � During the past five years NSO, using both NSF and USAF funding, has developed tunable, extremely narrow band imaging systems for both the visible and near-IR. These highly successful filters are based on using dual Fabry-Perot Etalons in tandem with 50-60 Å prefilters. Typical spectral resolution of the system is 40 mA in the visible and 100 mA in the near-IR. NSO has developed a near-IR magnetometer (NIM) and has started a program to upgrade it from a 256 × 256 IR camera to a 1K × 1K IR camera. NSO's plan for 1�5 micron observations is to take full advantage of NOAO's investment in the ALADDIN array development project. With 16 times as many pixels, higher quantum efficiency, lower read-out noise, and better immunity from electronic interference, the 1K × 1K ALADDIN-based camera will be superior to the current 256 × 256 camera in every respect and will enable new types of scientific observations, such as vector magnetograms of weak field concentrations and high-cadence studies of chromospheric dynamics. Implementing and demonstrating the scientific value of a fast, large-format infrared camera is an important component of NSO's preparation for an IR-capable Advanced Technology Solar Telescope.

High Altitude Observatory (HAO) � Innovative instrumentation has evolved repeatedly from leading-edge investigations by HAO scientists in collaboration with other national facilities, visitors, and university programs. The Advanced Stokes Polarimeter (ASP), Low Degree Oscillations Experiment (LOWL), Chromospheric Helium I Imaging Photometer (CHIP), Mk4, and STellar Astrophysics and Research on Exoplanets (STARE) are examples of HAO instrumentation efforts that were funded on the NSF base.

ASP was developed for high-resolution quantitative measurement of magnetic fields in the solar atmosphere. The instrument package was a joint project between NSO and HAO. The instrumental effort by HAO consisted of 25 effort years at a cost of $2.1M, of which $600,000 was in hardware. In March of 1993, the ASP was qualified as a user instrument available to members of the solar physics community. The ASP is universally recognized as the best instrument of its kind.

LOWL is unprecedented in its ability to perform velocity imaging with sufficient stability to observe low-degree acoustic oscillations. The instrument required six effort years and approximately $100K in hardware. The instrument�s elegant design allowed it to be deployed exactly two years after the date of the design review, at a fraction of the cost of comparable instrumentation. Since implementation, ~50 scientific papers have been published using LOWL data; 80% of these papers had primary authors outside HAO.

Mk4 white light coronameter was the final segment of the Advanced Coronal Observing System (ACOS). It was installed in October 1998, replacing the MK3 coronameter, which had been operating since 1980.

- 26 -

Improvements included a signal to noise three times greater than the MK3 instrument, a larger field of view, and improved spatial resolution. The larger field of view (1.08 to 2.85 solar radii) of the Mk4 provides greater overlap of these unique coronal images with the LASCO C2 coronagraph space-based images. This overlap allows for continual tracking of solar activity through the corona and provides the data necessary to cross calibrate the two instruments. Since 1996, nearly 90 scientific papers have been published using ACOS data; ~90% of these papers had primary authors outside HAO. The instrumental effort by HAO on ACOS consisted of 17 effort years at a cost of approximately $1.5M.

In 1997, HAO developed the STARE telescope. The principal purpose of this telescope was to detect extra-solar planets transiting the disks of their parent stars, by way of the dip in brightness that occurs as the planet blocks part of the stellar area. This project has so far required about $70K in hardware expenses and about 6 person-years of effort in construction, operations, and data analysis. Its most significant success has been the discovery of transits by the planet orbiting the star HD 209458 (Charbonneau et al., ApJ Lett, 529, L45 (2000)), leading to the first-ever measurement of the radius and density of an extra-solar planet.

C.10 Shared Costs This proposal covers critical telescope design trade studies, including proof-of-concept for heat management, contamination control and scattered light-reduction, and complete design and costing of the telescope, facilities, and instrumentation needed to achieve the scientific goals. Thus, it differs from more traditional proposals, which generally include design costs (including exploring and solving technical problems) in a single design and construction proposal that often results in poorly estimated costs. The result of the proposed upfront investment in a design and development phase will be an accurately costed construction proposal and the elimination of costly overruns.

The cost of $12.9M for the D&D phase roughly breaks down into $3M for instrument concept development and design, $3.5M for telescope technology development and trade studies, and $6.5M for telescope and facility design. It does not include proof-of-concept for high-order AO, which is being paid for with a $1.8M NSF/MRI proposal and matching funds from NJIT of $1M, base funds from NSO of $1M, and matching funds from the Kiepenheuer Institute of $1M. Nor does it include infrared camera technologies, which are being developed from the NSO, University of Hawaii, and HAO base budgets.

All of the partner organizations are contributing scientific manpower to the ATST program. Some are supporting additional graduate students and postdoctoral positions (not covered in the proposal) and making other in-kind contributions of labor and facilities. In addition to the contributed time of its scientists, HAO will invest several man-years of technical manpower in calibrating the site survey, and in development of prototype instrumentation for polarimetry at no additional cost to the proposal.

The FY01 NSO base budget of $6.5M from NSF provides $1.10M to operate NSO/T, $1.45M to operate NSO/SP, $2.2M to operate and upgrade GONG, and $480K to complete SOLIS. NSO is investing all of the remaining $1.07M in ATST development. This $1.07M includes $486K for adaptive optic development and $580K for building and deploying a set of site survey telescopes. The operational funds for NSO/T and NSO/SP include approximately $200K of project money, which is all being invested in instrumentation related to the ATST. This includes IR technologies and polarimeters that can exploit the diffraction-limited imaging being delivered by adaptive optics. In addition, a substantial fraction of the NSO science program covers scientists working on ATST-related technology such as adaptive optics, site testing, and IR technologies. NSO will continue this level of investment throughout the D&D phase (see the NSO Long Range Plan at http://www.sunspot.noao.edu).

Attempting to generate further ATST resources through additional reduction in current NSO operations would be a disaster for solar physics in the US. Discussions with the NSO Users� Committee and the reports of the NRC committee on ground-based solar astronomy and the Decadal Survey indicate that current NSO facilities are considered essential for the health of solar physics. Reducing their availability and productivity before better facilities are available will severely degrade the field. The leadership the US currently enjoys in solar facilities will be lost and the goal of recruiting the next generation of US solar physicists will be exacerbated. It is thus essential that new funds support the bulk of the design and development of the ATST as well as its construction.