ＡＴＳＴ(先端技術太陽望遠鏡）
・口径4m軸外しグレゴリアン太陽望遠鏡（究極の地上太陽望遠鏡）
分解能0.03“ @500nm、0.1” @1.6μ偏光精度 10^-4 （10^-5空間分解能を少し犠牲にしても十分高分解能）

波長域： 0.3～25μ、視野： <3‘
リム・コロナの観測・場所： ハワイ・アレヤカラ山頂（~3000m）（世界中のベスト・サイトをサーベイ）

・NSO（主）、主なUS太陽研究所、EU太陽研究所（観測装置）
・予算見積もり： 180 M$（NSF：120-130M$、他： 55-60M$）

・予定

環境問題クリア中
2008年秋？ 着工
2014年 ファーストライト日本との関係
・何度かメールにより所長クラスにコンタクトあったがかみ合わず
・昨年SacPeak WSの折に常田さんのSolar-Bの話に興味を持った、PIのS.
Keilが日本との協力関係を打診、11月に来日して、ATST説明会
・具体的な協力関係はまだ未定。
1. SOLAR-Bの結果をまず見たい
2. サイエンスWGに参加して、ATSTを勉強しつつ、日本の協力方針を決めたい。
サイエンスWGメンバー -> 末松 （今年から）
次回、サイエンスWG 10月中旬 @ハワイ

ATSTのサイエンス、具体的に何を目指すか
提案観測装置のレビュー

ATSTへの寄与
日本に何が期待されているか？
SOLAR-B可視光望遠鏡OTAで培った望遠鏡開発・製作技術？
ATST側からは特に具体的な希望は出ていない
主鏡？、望遠鏡構造？、、、という話もあるが望遠鏡の一部、facilityの一部を担うのは難しい（I/F、予算化）
現実的な寄与は、観測装置の1つを製作か日本しか開発できない装置はあるか？ 多分ない
しかし、2次元同時分光装置など特徴ある装置は提案できる。
ただ、これによる観測時間が確実に割り当てられるかは保証されない。
参加するか？ 何を？

Yes -> 誰が？

Test Energy Transport and Atmospheric Heating Models
Origins of Flares and CME’s
Solar Wind Acceleration
Predictive Space Weather Models, Sun-EarthObserve solar activity, evolution ofmagnetic structures, global magneticfield
Observe high-energy coronal andchromospheric structures-Flare and CME physics-Magnetic loop evolution andinstability

Observe fundamental plasmafield interactions on there
smallest scale.

ATST
Solar B
SDO
StereoObserve 3D coronal structure
Propagation into the interplanetary medium

Measure coronal andchromospheric magnetic fieldstrength-Magnetoconvection and
MHD models-Origins of Waves andoscillations, atmosphericheating-Drivers of magnetic
instabilities

Instrument

Fore-Optics

Dispersing System

Detector System

Visible-Light Broadband Imager

Phase Diversity

Interference Filters

VisibleVisible Spectropolarimeter

VisiblePolarization
Analyzer

Medium Dispersion
Spectrograph

Visible/C3PO

Near-IR disk&coronalSpectropolarimeter

Near-IR
Polarization
Analyzer

Medium Dispersion
Spectrograph(hot and cold)

NIR Hawaii II and/or C3PO

Visible Tunable Filter

VisiblePolarization
Analyzer

Interference Filters
Fabry-Perot

High frame rate visible
and/or C3PONIR Polarization
Analyzer

Interference Filters

NIR Hawaii II and/or C3PO

Near-IR Tunable Filter

Thermal-IR
Polarimeter&Spectrometer

Fabry-Perot
Medium resolution, cold
grating

Thermal IRVisible/Near-IR High-Dispersion
Spectrograph

VIS/NIRUV Polarimeter – Swiss
ContributionZimpol

Why ATST
Magnetoconvection•New Swedish Solar
Telescope– A moderate increase inaperture size has
already led to thediscovery of a numberof previously
unobserved finestructure such as dark
penumbral filament
cores

Courtesy of Goran Scharmer

Why an ATST
Coronal & Chromospheric Fields

Left: TRACE image of coronal loops (courtesy of A. Title). Right: Field extrapolationfrom photospheric field measurements (courtesy of Meudon Observatory).

“The most striking aspect of the subject of magnetic fields in• Extrapolating Coronal Magnetic Fields From PhotospherictheMeasurements
corona is thefrequency and variety of situations foris Difficult:whichthey are postulated, compared to the scarcity of any– Coronal Current Systems Lead to Non-Linear MHD Force Balance
definite
information concerning them.”– Boundary Condition Errors- from Donald E. Billings, A Guide to the Solar Corona, 1966.

Comparison with other Telescopes

Areal Resolution
10000

Resolved Area (km^2)

DSTTHEMIS

NSST
McMP

GREGOR, NST

1000

Predicted Magnetic Fibril sizes
ATST100050100150200

250

Aperture (cm)300350400450Comparison with other Telescopes
Fixed B, Fixed Size(assumes same sensitivity)

Relative Time

100DSTTHEMISNSST

10McMPGREGOR, NST

e.g. Moving Magnetic Flux Tube
ATST

10

50

100

150

200

250

Aperture (cm)

300

350

400450ATST Science Drivers

Transient
eruptions: flaresand coronalmass ejections

Heating ofchromosphereand corona,origin of solar
wind

Origin of solar
variability.
Dynamo(s)Surface andatmospherestructure anddynamics

Exploring theunknown

High Spatial, Spectral & Temporal Resolution
High Precision Polarimetry and SpectroscopyHigh Photon Flux
Near IR & Thermal Infrared
Scientific Drivers

 understandsources of spaceweather
 understand originof interstellar
matter understandstellar flares

Scientific Drivers

 understand solar
input to globalchange understand
irradiancevariation of solarlike stars

Scientific Drivers

 understand origin
and heating ofupper stellar
atmospheres
 understandaccretion disk
coronae

Scientific Drivers

 understand basic
MHD processes in
hot highly ionized
plamsa understandexcitation of stellar
p-mode oscillations

Scientific Drivers

 open newwindows
 provide bestsolar telescope in
the world:

The ATST Will:••

Clearly resolve fundamental astrophysical processes at the spatial
scale needed to test models
Provide a high photon flux for accurate and precise measurements ofphysical parameters throughout the solar atmosphere– High signal to noise spectro-polarimetry of magnetic field on its
elemental scale– Measure magnetic strength and direction, temperature and velocity, on
the short time scales of the dynamic solar atmosphere••

Directly measure coronal and chromospheric magnetic fields
Observationally test models of:–––––––•Magneto-convection
Flux emergence and annihilation
Flux transport
Flux tube formation and evolution
Sunspot magnetic fields and flows
Atmospheric heating
Solar Activity

Enable, complement and enhance planned space missions

Telescope Requirements• Aperture:4m•

diffraction limited:

Resolution:- within isoplanatic patch (conventionalAO)- over ~2 arcmin using MCAO (upgrade)•

Adaptive Optics:
seeingStrehl ratio: >0.3 , goal of S > 0.6 during good

•

FOV:

3 arcmin (goal 5 arcmin)•Wavelength Coverage: 300 nm - 28 micronUnprecedented Spatial Resolution
with 4m ApertureWavelength

AngularResolution

LinearResolution(1.22 λ/D)(km)

0.5 μ0.”03

23

1.6 μ0.”175

4.8 μ0.”3225

12 μ0.”75560

Q: Do we ALWAYS want to work at the diffraction limit?
A: NO!!
Trade-offs between: spatial, temporal spectral, resolution, S/N.

NeedPhotons, Photons and more photons
Diffraction limited observations: We are quickly running outof photons!!
Example:• Weak field 100G,• spatially resolved, 0.”1 pixel , Moderate Spectral
Resolution: R=300000• Need S/N ~ 2000 to measure B+/-25G, direction+/- 6 deg.
(Skumanich et al. 1997)• feature moves horizontally by 0.5 pix in only 5 sec (soundspeed)• Need 4m aperture to collect enough photons within 5 sec• Things just get worse in the Chromosphere and Corona!

Flow Down I
Science to Telescope Design
18 use cases lead to specific high-level requirements:•Resolution: 0.03 arcsec (25 km) at 500 nm
 4-meter aperture working at the diffraction limit
 High-order adaptive optics, MCAO upgrade option
 Minimal self-induced seeing•

Photon flux: Integration times as short as 1 msec at spectral resolution as
high as 1-2 picometers 12 m2 collecting area (4-meter aperture)•

Wavelength coverage: 300 nm to 28 m
 All-reflecting optics, no windows, no evacuated column•

Scattered light and coronagraphy: 2.5×10-5 of on-disk irradiance 1.1 solar
radii (1.6 arcmin) above the limb
 Off-axis optical design
 Prime-focus occulting In-situ mirror cleaning and washing Filtered air

Flow Down II
Science to Telescope Design•

Field of view: 3 arcmin unvignetted
 Gregorian optical configuration allowing heat-rejection
opportunity at prime focus•

Polarimetry: Sensitivity of 5x10-5 I0

 Facility-level signal modulation and analysis
 Specialized facility-level charge-caching detector packages•

Operational modes: Highly flexible, multi-instrument configurations arerequired Large coudé observing area
 High level of instrumental commonality
 Innovative instrument-control software•

Lifetime: 30 to 40-year life expectancy
 Flexible design with upgrade paths

Telescope Requirements••

Aperture:Resolution:4m
diffraction limited:- within isoplanatic patch (conventional AO)- over ~2 arcmin using MCAO (upgrade)• Adaptive Optics:

Strehl ratio: >0.3 , goal of S > 0.6 during
good seeing•
•
•
•
•

FOV:
Wavelength Coverage:
Polarization Accuracy:
Polarization Sensitivity:
Low Scattered Light:•••

Coronagraph:
Flexibility:
Adaptability:

3 arcmin (goal 5 arcmin)
300 nm - 28 micron
10-4 (low instrumental polarization)
limited by photon statistics down to 10-5
e.g. sunspots: 1% of surrounding photosphere
Corona: < 10-5 at R= 1.1R; = 1
in the NIR and IRe.g., Combine various post-focus instrumentse.g., try out new ideas, bring your own
instrument

Adaptive Optics for the ATST
Visible (500nm)

High Strehl Requirement leads to large number ofDoFs

Adaptive Optics for the ATSTNIR (1.6 )
High Strehls are fairly easy to achieve!

Model data: Stein, Nordlund & Keller

ATST
medianseeing

ATST goodseeing

4m in space

Input dataSpace Missions with High Resolution
Polarimetry Capabilities

resolution

wavelength

Time resolution for 160”
scanSolar-B0.”26 (630nm)

630.2 nm

80 minSDO1” – full disk

Limited to 1wavelength

5 minFilter basedpolarimeter

ATST0.”03 (630nm)

300 nm – 12
micronfew min @ 0.”2
resolution