Advanced

TTTechnology

Solar

TTTelescope

http://atst.nso.edu

The ATST Project is funded by the National Sci-ence Foundation (NSF) through the National Solar Observatory, which is operated under a cooperative agreement between the Association of Universities for Research in Astronomy, Inc. (AURA) and NSF.

National Solar ObservatoryP.O. Box 62Sunspot, NM 88349-0062

AURA

National Solar ObservatoryHigh Altitude ObservatoryNew Jersey Institute of TechnologyUniversity of HawaiiUniversity of ChicagoUniversity of RochesterUniversity of ColoradoUniversity of California Los AngelesUniversity of California San DiegoCalifornia Institute of TechnologyPrinceton University

Stanford UniversityMontana State UniversityMichigan State UniversityCalifornia State University NorthridgeHarvard-Smithsonian Center for AstrophysicsColorado Research AssociatesSouthwest Research InstitutionAir Force Research LaboratoryLockheed MartinNASA/Goddard Space Flight CenterNASA/Marshall Space Flight Center

Current ATST collaborators

Project Director: Stephen L. KeilProject Scientist: Thomas R. RimmeleProject Manager: Jeremy Wagner

Edited images of Earth depict the blurred (1") view we once had of solar activity and the clarity afforded now with adaptive optics on the Dunn Solar Telescope (0."14). The leap forward with ATST (0."03) will be like the difference between barely detecting storms, and making movies that reveal their fi ne-scale structure and activities.

The ATST will be unique in its ability to resolve fundamental length and time scales of the basic physical processes governing variations in solar activity. Just as other fundamental problems in atomic, nuclear, and gravitational physics were revealed through earlier studies in solar physics, the ATST will have a broad impact on astronomy, plasma physics, and solar-terrestrial relations.

The ATST will achieve a spatial resolution nearly an order of magnitude better than any existing solar telescope. It will resolve, for example, the magnetic structures in the solar atmosphere that are responsible for the majority of solar variability. The main strength of ATST will be precision spectroscopy and polarimetry throughout the entire solar atmosphere. The large aperture will let scientists perform quantitative observations of small, fast phenomena. These capabilities come at a time of great progress in realistic models of magnetoconvection and will enable direct comparisons between observations and theory.

Advances in adaptive optics, infrared, polarization, and other instrumentation will let the ATST achieve these goals, making it the logical successor to solar telescopes built in the 1960s and ’70s. Its aperture, performance, and spectroscopic capabilities will complement current and planned space missions. As a ground-based facility, it will have a 50-year life and will grow in capability as new technologies emerge and are incorporated into it. The ATST will be a powerful, fl exible system that will serve the U.S. and international solar physics community for many decades.

Engineering concept of ATST at Haleakala.

ATST concepts (cover, back panel, center inside): LeEllen Phelps, NSO.Earth (back panel): NASA Blue Marble Project.Inside panels: Sun—OSPaN, Air Force Research Laboratory. Bottom center—NSO and

OSPaN; NSO and HAO; NSO and Arcetri Solar Physics Group.Other graphics and design: Dave Dooling, NSO.

©2008 NSO/AURA/NSF

1/2 relative size

Advanced Technology Solar TelescopeCollaborating Institutions

National Solar ObservatoryHigh Altitude ObservatoryNew Jersey Institute of TechnologyUniversity of HawaiiUniversity of ChicagoUniversity of RochesterUniversity of ColoradoUniversity of California Los AngelesUniversity of California San DiegoCalifornia Institute of TechnologyPrinceton UniversityStanford UniversityMontana State UniversityMichigan State UniversityCalifornia State University NorthridgeHarvard-Smithsonian Center for AstrophysicsColorado Research AssociatesSouthwest Research InstitutionAir Force Research LaboratoryLockheed MartinNASA/Goddard Space Flight CenterNASA/Marshall Space Flight Center

As of June 2008(International partnerships

being developed)

a d v a n c e d t e c h n o l o g y s o l a r t e l e s c o p ea d v a n c e d t e c h n o l o g y s o l a r t e l e s c o p e

ATST Schedule2002 Start site testing. Develop adaptive optics (AO), other

technologies.2003 Design concept fi nalized. High-order AO demonstrated.2004 Haleakala, Maui, selected as prime site.2006 Preliminary design review; environmental impact assessment.2009 Start construction.2014 Start integration.2016 “First light.” Start operations.

Updated June 2008; schedule subject to change.

Then

Engineering concept of ATST at Haleakala.-Engineering concept of ATST at Haleakala.

Haleakala, Maui, selected as prime site.-Haleakala, Maui, selected as prime site.

Now ATST

... To enable detailed investigations that ...

... use infrared data to develop and test models of flares and coronal mass ejections that spew into space and drive geomagnetic disturbances.

… use high spatial resolution to measure interactions of the solar atmospheric plasma with magnetic fi elds on their fundamental scales to test models.

… use high polarization sensitivity to measure the strength and direction of magnetic fi elds that permeate the solar atmosphere and produce active regions, sunspots, and other structures.

Four centuries after the start of modern astronomy, the Sun still hides many secrets from us. During the 20th century we learned that magnetic fi elds are a fundamental part of most of the activities we see on the Sun’s surface and are crucial, sometimes controlling, features in other stars, black holes, even whole galaxies. But defi nitive explanations elude us. To understand our Sun, and the universe around us, scientists ask:

• What are the basic mechanisms responsible for solar variability (sunspots, fl ares, etc.) that ultimately affect human technology, human activities in space, and climate on Earth?

• How are solar and stellar magnetic fi elds generated and destroyed?

• What role do magnetic fi elds play in plasma structures and the explosive releases of energy in solar fl ares and throughout the universe?

Answering these important questions requires seeing fi ne structures (high spatial resolution) in narrowly defi ned colors (high spectral resolution) on short time scales (fast temporal resolution). Despite the Sun’s brightness, increasing the resolution in these three areas severely limits the available light, thus leaving solar physicists as “photon starved” as nighttime astronomers. The solution is a large aperture solar telescope supporting an array of large, advanced science instruments.

To meet this challenge, the 4-meter Advanced Technology Solar Telescope (ATST) will provide the resolution and capability needed to grasp answers beyond the reach of today’s solar instruments. ATST will be an unprecedented facility, supporting world-class science from its “fi rst light” in 2016 through much of the 21st century. It will be an indispensable tool for exploring and understanding physical processes on the Sun that ultimately affect Earth.

ATST scientifi c drivers

The primary goal of the ATST is to provide critical observations needed to understand the fundamental physical processes underlying solar magnetic activity and variability. These drive space weather and the hazards it creates for human activities such as communications and military satellites, astronauts, and occasionally air travelers. Major questions for the ATST include:

• How are the highly intermittent magnetic fi elds observed at the solar surface generated? How are they dissipated?

• What magnetic confi gurations and evolutionary paths lead to fl ares and coronal mass ejections?

• What mechanisms are responsible for variations in the dynamo that drives the sunspot cycle and the Sun’s energy output?

4-meter (13-ft) aperture: High resolution and light fl ux to see fi ne, rapidly changing magnetic structures at narrow wavelengths.

Off-axis Gregorian telescope: Clear aperture to reduce scattered light, manage heat load, access near-UV to far-IR spectrum, on disk and into the near corona.

Hybrid telescope enclosure: Mitigate dome-induced seeing problems.

High-order adaptive optics: Compensate for blurring by Earth’s atmosphere.

Internal seeing, contamination control: Reduce scattered light, blurring.

Cutting-edge instrumentation: Precise measurements of magnetic fi elds, velocities, other physical parameters.

... Lead to innovative designs ...

High sensitivity: Obtain detailed spectra of fi ne structures in shorter time intervals.

Field of view: Up to 5 arc-minutes (1/6th Sun’s diameter) to cover large active regions.

Wavelength range: Near ultraviolet to thermal infrared to diagnose multiple heights and activities.

Spatial resolution: Better than 0.03 arc-second (1/64,000th Sun’s diameter) to see solar magnetic fi elds at their fundamental scales.

Polarization accuracy: 1/10,000th of intensity for precise measurements of magnetic fi elds.

Scattered light: Coronagraphic in near-infrared to explore coronal magnetic fi elds.

Location: Best combination of seeing, sunshine hours and sky clarity.

Challenging performance criteria ...

…to inner corona

The Sun’s spectrum extends far beyond the visible light we know in our daily lives. ATST will give scientists the ability to probe deep in the infrared to explore currently unknown aspects of solar activities.

300 ~380 ~770 1,000 10,000 28,00020,0005,000

VisibleUV Near IR Thermal IR

ATST spectral range (nm)

From disk center …

IntensityI Q U V

20"

Polarization

Earthdiameter