Transcript New initiatives - Major Instrumentation - CDS - u

Future Giant Telescope (FGT) Projects
and Their Technological Challenges
IAU Joint Discussion 8
July 17, 2003
Larry Stepp
AURA New Initiatives Office
Outline
• Introduction: how FGTs will advance beyond currentgeneration telescopes
• A brief history of FGTs
• Current concepts for FGTs
• Technology challenges common to all
AURA New Initiatives Office
Current-Generation Telescopes
• 8- to 10-meter telescopes have achieved better
performance at lower relative cost by reducing the
size and mass of telescope & enclosure
– Improvements in polishing and testing techniques have
enabled faster primary mirrors
– Active optics has achieved tighter alignment tolerances and
enabled mirrors to be made lightweight
– Faster primaries, lighter mirrors, alt-azimuth mounts & FEA
have resulted in smaller, stiffer telescope structures
– Smaller, stiffer structures have allowed enclosures to be
smaller and better ventilated, improving local seeing
• As a result, sub-half-arc-second images are becoming
commonplace
AURA New Initiatives Office
Mayall  Keck
• Cost in 1973: $10.6 M
• Adjusted to 1992: $33.7 M
• Projected cost of 10m in
1992: $400 M
350 tonnes
• Actual cost of Keck 10m
telescope in 1992: $110 M
270 tonnes
AURA New Initiatives Office
Future Giant Telescopes
• FGTs will continue the trends of the current generation
– Faster primary focal ratios
– Relatively lighter structures
• And they will advance beyond the Current Generation
– Integral adaptive optics systems
– Smart structures
• This will enable FGTs to have:
– An order of magnitude more light-gathering power
– Better image quality and resolution
• Diffraction-limited at  > 1 micron
• However, significant technological challenges must be
solved to make this possible
AURA New Initiatives Office
A Brief History of Future Giant Telescopes
The Kitt Peak Next Generation Telescope
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25-m telescope
Segmented f/1 primary
Radio-telescope style mount
Concept from 1977
AURA New Initiatives Office
A Brief History of Future Giant Telescopes
The National New Technology Telescope (NNTT)
• 16-m telescope
• MMT-type
• Four 8-m f/1.8 primary
mirrors
• Concept from 1986
AURA New Initiatives Office
A Brief History of Future Giant Telescopes
More Concepts Were Advanced in the Early 1990s
J. R. P. Angel, Filled Aperture Telescopes in the Next Millennium, SPIE
1236, 1990.
A. Ardeberg, T. Andersen, B. Lindberg, M. Owner-Petersen, T. Korhonen,
P. Søndergård, Breaking the 8m Barrier - One Approach for a 25m Class
Optical Telescope, ESO Conf. and Workshop Proc. No. 42, 1992.
M. Mountain, What is beyond the current generation of ground-based 8-m
to 10-m class telescopes and the VLT-I?, SPIE 2871, 1996.
F. N. Bash, T. A. Sebring, F. B. Ray, L. W. Ramsey, The extremely large
telescope: A twenty-five meter aperture for the twenty-first century, SPIE
2871, 1996.
V. V. Sytchev, V. B. Kasperski, S. M. Stroganova, V. I. Travush, On
conceptual design options of a large optical telescope of 10...25 metre
class, SPIE 2871, 1996.
AURA New Initiatives Office
Current Concepts for FGTs
Large Aperture Telescope (LAT)
• LAT Consortium
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Cornell
Chicago
Illinois
Northwestern
• Site: high Atacama desert or
Antarctica
Design concept for LAT
From a presentation by Ed Kibblewhite
AURA New Initiatives Office
Large Aperture Telescope (LAT)
Interesting Features of Concept:
• Adaptive primary mirror
– Design shown would have 36-m primary with 28-m adaptive
central zone
• Science goals emphasize IR and sub-millimeter wavelengths
• Low PWV sites provide logistical challenges
AURA New Initiatives Office
Large Aperture Telescope (LAT)
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
TBD
20-m to 36-m
TBD (~ f/1)
TBD
TBD
5’ - 10’
Cassegrain
Below primary mirror
AURA New Initiatives Office
Large Aperture Telescope (LAT)
Key Technical Challenges
– Cost-effective fabrication of lightweight, off-axis aspheric
segments
– Structure needs high damping
– Momentum compensation for adaptive segments
– Efficient segment co-phasing systems
– Laser guidestar beacons
– Site survey studies of CN2 profile
More information is available at:
http://astrosun.tn.cornell.edu/atacama/atacama.html
AURA New Initiatives Office
Magellan 20
• Partner organizations include:
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Carnegie
Harvard
Smithsonian
MIT
Arizona
Michigan
• Site: Las Campanas, Chile
Design Concept for Magellan 20
From a presentation by Roger Angel
AURA New Initiatives Office
Magellan 20
Interesting Features of Concept:
• Primary consists of seven 8.4-m mirrors
• Segmented, adaptive secondary
• Ground-conjugate adaptive
optics
• Allows later incorporation
into a 20-20 interferometer
AURA New Initiatives Office
Magellan 20
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Aplanatic Gregorian
26-m (22-m equiv.)
f/0.7
2.5-m
f/10
12’ - 20’
Nasmyth
Nasmyth (vertical)
Cassegrain
Below primary mirror
AURA New Initiatives Office
Magellan 20
Key Technical Challenges
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Fabrication & testing of highly-aspheric 8.4-m off-axis segments
Segmented adaptive secondary mirror
Laser guidestar beacons
Multi-conjugate adaptive optics
More information is available at:
http://helios.astro.lsa.umich.edu/magellan/intro/science_case_march16.htm
AURA New Initiatives Office
High Dynamic Range Telescope
• Design developed by:
– Univ. of Hawai’i
• Site: Mauna Kea, Hawai'i
– (replace the CFHT)
Design concept for HDRT
From a paper by Kuhn et al
AURA New Initiatives Office
High Dynamic Range Telescope
Interesting Features of Concept:
• Rapidly switchable narrow-field & wide-field modes
• Segmented
secondary mirrors
• Concept for bi-parting
enclosure
• Adaptive structure
AURA New Initiatives Office
High Dynamic Range Telescope
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
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Tertiary mirror diameter
Final focal ratio
Field of View:
Instrument locations:
Elevation axis location:
Gregorian (NF)
3-mirror anastigmat (WF)
22-m (16-m equiv.)
f/1
six @ 0.14-m (NF)
six @ 2.3-m (WF)
7-m
f/15 (NF); f/1.9 (WF)
3” (NF); 2 degrees (WF)
Central
Above primary mirror
AURA New Initiatives Office
High Dynamic Range Telescope
• Key Technical Challenges
– Fabrication of & testing of 6.5-m off-axis aspheric primary
mirror segments
– Fabrication & testing of 2.3-m off-axis secondary mirror
segments
– Adaptive telescope structure
– Laser guidestar beacons
More information is available at:
http://www.ifa.hawaii.edu/users/kuhn/hdrt.html
AURA New Initiatives Office
Large Petal Telescope
• Design developed by:
– Obs. Astron. MarseilleProvence
– Obs. Astron. de Paris
• Site: Mauna Kea, Hawai'i
– (replace the CFHT)
Design concept for LPT
From a paper by Burgarella et al
AURA New Initiatives Office
Large Petal Telescope
Interesting Features of Concept:
• Primary consists of six or eight 8-m sector-shaped,
meniscus segments
• 3-mirror or 4-mirror
optical design
• Simultaneous use of
6-8 instruments
• Adaptive telescope
structure
AURA New Initiatives Office
Large Petal Telescope
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
3- or 4-mirror anastigmat
20-m +
f/1
2.5-m to 5-m
f/5 to f/7.5
1 degree
Cassegrain
Below primary mirror
AURA New Initiatives Office
Large Petal Telescope
• Key Technical Challenges
– Fabrication & testing of 8-m off-axis aspheric primary mirror
segments
– Fabrication & testing of secondary mirror
– Adaptive telescope structure
– Multi-conjugate adaptive optics
– Laser guidestar beacons
More information is available at:
http://www.astrsp-mrs.fr/denis/ngcfht/ngcfht.html
AURA New Initiatives Office
Very Large Optical Telescope (VLOT)
• Design developed by:
– HIA
– AMEC
• Site: Mauna Kea, Hawai'i
– (replace the CFHT)
Design Concept for VLOT
AMEC Dynamic Structures
AURA New Initiatives Office
Very Large Optical Telescope (VLOT)
Interesting Features of Concept:
• Considering concept with 8-m diameter central mirror
surrounded by sector-shaped smaller segments
• Calotte dome concept
AURA New Initiatives Office
Very Large Optical Telescope (VLOT)
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Ritchey-Chrétien
20-m
f/1
2.5-m
f/15
20’
Nasmyth (vertical)
Below primary mirror
AURA New Initiatives Office
Very Large Optical Telescope (VLOT)
Key Technical Challenges
– Cost-effective fabrication of lightweight, off-axis aspheric
segments
– Fabrication & testing of secondary mirror
– Laser guidestar beacons
– Multi-conjugate adaptive optics
– Laser guidestar beacons
More information is available at:
http://www.hia-iha.nrc-cnrc.gc.ca/VLOT/index.html.
AURA New Initiatives Office
California Extremely Large Telescope (CELT)
• CELT Partnership
– Caltech
– Univ. of California
• Site: TBD (Mauna Kea
or northern Chile or
Mexico)
Design concept for CELT
From the CELT Greenbook
AURA New Initiatives Office
California Extremely Large Telescope (CELT)
Interesting Features of Concept:
• Scaled up Keck design with
1080 segments arranged in
91 rafts
• Large Nasmyth platforms
AURA New Initiatives Office
California Extremely Large Telescope (CELT)
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Tertiary mirror major axis
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Ritchey-Chrétien
30-m
f/1.5
3.96-m
4.38-m
f/15
20”
Nasmyth
Above primary mirror
AURA New Initiatives Office
California Extremely Large Telescope (CELT)
• Key Technical Challenges
– Cost-effective fabrication of 1080 off-axis aspheric primary
mirror segments
– Fabrication & testing of secondary mirror
– Fast tip-tilt-piston of secondary and tertiary mirrors
– Efficient segment co-phasing systems
– Laser guidestar beacons
– Multi-conjugate adaptive optics
More information is available at:
http://celt.ucolick.org/
AURA New Initiatives Office
Giant Segmented Mirror Telescope
• Design by AURA New
Initiatives Office
– NOAO
– Gemini
• Site: TBD (Mauna Kea
or northern Chile or
Mexico)
Design Concept for GSMT
From animation by Rick Robles
AURA New Initiatives Office
Giant Segmented Mirror Telescope
Interesting Features of Concept:
• Prime focus instrument
• Aperture stop at secondary
• Adaptive secondary
AURA New Initiatives Office
Giant Segmented Mirror Telescope
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Cassegrain (or R-C)
32-m (30-m equiv.)
f/1
2-m
f/18.75
20”
Prime focus
Nasmyth
Cassegrain (moving & fixed)
Below primary mirror
AURA New Initiatives Office
Giant Segmented Mirror Telescope
• Key Technical Challenges
– Cost-effective fabrication of 618 off-axis aspheric primary
mirror segments
– Efficient segment co-phasing systems
– Adaptive secondary mirror
– Laser guidestar beacons
– Multi-conjugate adaptive optics
– Adaptive telescope structure
More information is available at:
www.aura-nio.noao.edu/
AURA New Initiatives Office
Euro50
• Euro50 partners
– Lund University
– Inst. de Astrofisica de
Canarias
– Dept. of Physics,
Galway, Ireland
– Tuorla Observatory
– Optical Science Lab.
– National Physical Lab.
• Site: La Palma
Design Concept for Euro50
From Euro50 web site
AURA New Initiatives Office
Euro50
Interesting Features of Concept:
• Adaptive secondary with composite
face sheet
• F/5 focal reducer for seeing-limited
observing
AURA New Initiatives Office
Euro50
Design Parameters
• Optical design:
• Primary mirror diameter
• Primary mirror focal ratio
• Secondary mirror diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Gregorian
50-m
f/0.85
4-m
f/13; also: f/5; f/16; f/20
4’
Nasmyth
Folded Cassegrain
Below primary mirror
AURA New Initiatives Office
Euro50
• Key Technical Challenges
– Cost-effective fabrication of 618 off-axis aspheric primary
mirror segments
– Efficient segment co-phasing systems
– Adaptive secondary mirror
– Laser guidestar beacons
– Multi-conjugate adaptive optics
More information is available at:
http://www.astro.lu.se/~torben/euro50/
AURA New Initiatives Office
Overwhelming Large Telescope (OWL)
• Design by European
Southern Observatory
• Site: TBD
Design Concept for OWL
From OWL web site
AURA New Initiatives Office
Overwhelming Large Telescope (OWL)
Interesting Features of Concept:
• Spherical primary mirror
• Flat segmented secondary mirror
• Three aspheric mirrors
• Elevation assembly
recessed into ground
• Mount tied to ground by
multiple drive bogies
AURA New Initiatives Office
Overwhelming Large Telescope (OWL)
Design Parameters
• Optical design:
• Primary mirror (M1) diameter
• Primary mirror focal ratio
• Secondary mirror (M2) diameter
• M3 diameter
• M4 diameter
• M5 diameter
• Final focal ratio
• Field of View:
• Instrument locations:
• Elevation axis location:
Six-mirror design
100-m
f/1.42
26-m
8.1-m
8.2-m
3.5-m
f/7.5
10’
Central
Above primary mirror
AURA New Initiatives Office
Overwhelming Large Telescope (OWL)
• Key Technical Challenges
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Fabrication of large numbers of lightweight segments
Active structure to move corrector
Efficient segment co-phasing systems
Multi-conjugate adaptive optics
2.4-m adaptive flat mirror
3.5-m adaptive curved mirror
More information is available at:
http://www.eso.org/projects/owl/
AURA New Initiatives Office
Required Technology Developments:
Telescope & Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Lightweight 1-m to 2-m segments
Large numbers of aspheric segments
Fab & test of large aspheric segments
75-cm lightweight segment
Active/adaptive structure
Fab & testing of large, convex M2s
High-reflectivity durable coatings
Efficient segment co-phasing systems
Large, fast tip-tilt-piston mirrors
AURA New Initiatives Office
Required Technology Developments:
Telescope & Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Lightweight 1-m to 2-m segments
Large numbers of aspheric segments
Fab & test of large aspheric segments
Active/adaptive structure
Fab & testing of large, convex M2s
High-reflectivity durable coatings
Efficient segment co-phasing systems
Large, fast tip-tilt-piston mirrors
AURA New Initiatives Office
Required Technology Developments:
Adaptive Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Improved analysis & simulation
Large adaptive mirrors
MOEMS deformable mirrors for EXAO
MCAO system designs
Laser guidestar beacons
Large-format, fast, low noise detectors
Wavefront rec. & fast signal processors
Site testing of CN2 distribution
AURA New Initiatives Office
Required Technology Developments:
Adaptive Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Improved analysis & simulation
Large adaptive mirrors
MOEMS deformable mirrors for EXAO
MCAO system designs
Laser guidestar beacons
Large-format, fast, low noise detectors
Wavefront rec. & fast signal processors
Site testing of CN2 distribution
AURA New Initiatives Office
Required Technology Developments:
Adaptive Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Improved analysis & simulation
Large adaptive mirrors
MOEMS deformable mirrors for EXAO
MCAO system designs
Laser guidestar beacons
Large-format, fast, low noise detectors
Wavefront rec. & fast signal processors
Site testing of CN2 distribution
LLNL – ESO – CfAO
sum-frequency fiber laser
AURA New Initiatives Office
Required Technology Developments:
Adaptive Optics
Required Development
Possibly Required
L M H L
A 2 D P
T 0 R T
T
V
L
O
T
C
E
L
T
G E O
S 5 W
M 0 L
T
Improved analysis & simulation
Large adaptive mirrors
MOEMS deformable mirrors for EXAO
MCAO system designs
Laser guidestar beacons
Large-format, fast, low noise detectors
Wavefront rec. & fast signal processors
Site testing of CN2 distribution
AURA New Initiatives Office
Required Technology Developments:
Instruments
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•
•
•
•
•
•
•
Affordable large near-IR detectors
Affordable large mid-IR detectors
Advanced image slicers for IFUs
Fiber positioners
MOEMS slit masks for multi-object spectroscopy
Large-format volume-phase holographic gratings
Large-format immersed silicon gratings
Large lenses & filters
AURA New Initiatives Office
Call For International Cooperation
Our needs are so similar and our resources are limited,
close cooperation is essential:
• Joint ventures where sensible
• Coordination to ensure studies are complementary
• Open sharing of information as much as possible
AURA New Initiatives Office