Gemini AO Program
The Gemini Adaptive Optics Program
MCAO for Gemini-South
F.Rigaut and B.Ellerbroek
Presentation Overview:
• Dedication success
• The Gemini Adaptive Optics Program Revisited
• Multi-Conjugate Adaptive Optics:
•A Science Opportunity: Context and rationale
•Principles and performance
•Feasibility
•Cost and Schedule
November 15, 1999
Gemini Board
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Gemini AO Program
Gemini’s Dedication
BD30: Courtesy C.Roddier, UH-IfA
November 15, 1999
Gemini Board
2
Gemini AO Program
Gemini Top Level Performance
Requirement #2
“ Image quality of better than 0.1 arcsec with AO:
Achievement of outstanding image quality will have
the highest scientific priority for the project […]”
• 85% of the science topics in the Abingdon report
need AO to be “effectively addressed”
• The proposed evolution of the program at CP will
enable unique NGST-class science 4 years ahead of
NGST launch. It will keep Gemini competitive during
the NGST era
November 15, 1999
Gemini Board
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Gemini AO Program
Proposed Baseline AO Program
Doing AO Since 1989 (Come-On, ESO 3.6-m)
NORTH
1999
2000
2001
2002
2003
2004
•Facility VLT AO : NAOS+Conica
•AO/Integral field unit: MACAO
•4 AO systems for the VLTI
Altair
10W LGS
Hokupa’a
SOUTH
36
Keck
85
Subaru
VLT
CP AOS/LGS
CP Hokupa’a
85
1’’
3 Years Gap
Vesta 1.5 m
FWHM<40mas
2W LGS
November 15, 1999
VLT-LGS
Gemini Board
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Gemini AO Program
Baseline Program: Facility CP AOS
SOUTH
1999
2000
2001
2002
2003
2004
CP AOS/LGS
Context:
• The Gemini science mission relies heavily on high angular resolution
• Other observatories have “high performance” AOSs in the north
(Keck 1999) and in the south (VLT 2001) -> Competitiveness issue
Rationale:
• Provide the Gemini community with NGST-like capabilities (spatial res.
and field), matching the Gemini science goals and instrumentation
• Sets up Gemini to be a lead ground-based facility in the NGST era
with matching resolution and similar field of view
• Future ELTs require “wide” field of view AO
November 15, 1999
Gemini Board
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Gemini AO Program
Baseline Program: Facility CP AOS
SOUTH
1999
2000
2001
2002
2003
2004
CP AOS/LGS
Proposal:
• Build a high performance, 2 arcminutes field of view AOS with
homogeneous PSF quality over the entire field of view, with very high
sky coverage
How ?
• Using Multi-Conjugate AO, i.e. 4-5 LGSs and wavefront sensors to
measure the turbulence in 3D and 2-3 deformable mirrors to correct it
• This uses currently available technology. NO hardware development
required other than lasers (same as MK-LGS)
November 15, 1999
Gemini Board
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Gemini AO Program
What is Tomography ?
90 km
1. Cone effect
November 15, 1999
“Missing” Data
Gemini Board
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Gemini AO Program
What is Tomography ?
90 km
2. Multiple guide star and tomography
November 15, 1999
Gemini Board
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Gemini AO Program
What is multiconjugate?
Turbulence Layers
Deformable mirror
November 15, 1999
Gemini Board
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Gemini AO Program
What is multiconjugate?
Deformable mirrors
November 15, 1999
Turbulence Layers
Gemini Board
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Gemini AO Program
Effectiveness of MCAO
Numerical simulations:
• 5 Natural guide stars
• 5 Wavefront sensors
• 2 mirrors
• 8 turbulence layers
• MK turbulence profile
• Field of view ~ 1.2’
• H band
November 15, 1999
Gemini Board
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Gemini AO Program
MCAO Performance Summary
Early NGS results, MK Profile
No AO
320 stars / K band / 0.7’’ seeing
November 15, 1999
Classical AO
MCAO
1 DM / 1 NGS
2 DMs / 5 NGS
165’’
Gemini Board
Stars magnified for clarity
12
Gemini AO Program
Sample Numerical Results
0 degree zenith
• 50% seeing
• CP turbulence profile
• K band
• 12x12 subapertures
• NGS-AO (triangles)
• MCAO with 5 LGSs and 3
Tip-tilt NGS (crosses)
•
K
H
J
I
November 15, 1999
Gemini Board
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Gemini AO Program
Baseline Program: Facility CP AOS
SOUTH
1999
2000
2001
2002
2003
2004
CP AOS/LGS
Advantages of MCAO versus Classical AO :
 Sky coverage (50%) increased (50-500x) w/ respect to a NGS
system
 Increased performance on axis w/ respect to a LGS system because
the cone effect is compensated
 Increased field of view (well matched to IRMOS)
 Uniform PSF across the FoV -> Easier and more accurate Data
Reduction
November 15, 1999
Gemini Board
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Gemini AO Program
MCAO Implementation-
Feasibility study conclusions:
•
•
•
•
•
•
Optics and optics bench
– Mass, volume similar to Altair
Wave front sensor camera
– Goal of a single camera for all laser guide stars
– 80 by 80 to 128 by 128 pixels, 5 to 10 read noise electrons
Deformable mirrors and tip/tilt mirror
– Number of actuators, other parameters demonstrated
Wave front reconstruction electronics
– Frame rate, number of inputs/outputs demonstrated
– Flexible algorithms and architectures necessary for NGS tip/tilt
measurements
Tip/tilt sensors, laser transfer optics and launch telescope
– Appear straightforward, feasibility designs in progress
– 2-3 T/T sensors + 1 more provided by OIWFS
Laser(s): Technology and engineering development required
November 15, 1999
Gemini Board
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Gemini AO Program
MCAO Science Optical Path
•3 DM’s at R=0, 4, and 8 km
•13 actuators across beamprint
•4 folds, 2 off-axis parabolas,
1 dichroic beamsplitter (not shown)
- Near-minimum number of surfaces for
facility MCAO
• f/30 output focus
November 15, 1999
Gemini Board
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Gemini AO Program
Laser Issues
• Power requirement:
– Equivalent to conventional LGS AO on a per beacon basis
– 20-40 Watts per LGS, 80-200 Watts total for short pulse,
flashlamp+Nd:YAG-pumped dye lasers (LLNL)
• ~20 Watts demonstrated
• Scaling a cost/engineering issue (electrical power, heat
dissipation, flammable dye)
– 7-12 Watts per LGS, 28-60 Watts total for diode-pumped,
Nd:YAG sum frequency lasers (MIT/LL and others)
• ~5 Watts demonstrated
• Scaling a technical issue (Nd:YAG beam quality and sum
frequency feasibility at higher powers)
November 15, 1999
Gemini Board
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Gemini AO Program
Baseline Schedule
2000
2001
2002
2003
2004
Duration O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M
1632 days
ID Task Name
1 CP LGS M CAO System
2
• Conceptual design
Conceptu al Design
632 days
3
CP Sight Characterization
4
Science and System Implimentation Review
review: 3/00
5
CoD Forum
6
Review Forum
7
System Concept Development
8
System Requirements Review (Gemini Board)
• Preliminary design
reviews: 12/00
9
System Conceptual Design
10
Conceptual Design Review
11
Subsystem Requirements and Interface Description
• Critical design
reviews: 12/01
• Subsystems
complete: 6/03
• System
integration and
test: 10/03
12
November 15, 1999
65 days
1 day
22 days
152 days
1 day
87 days
0 days
799 days
Prelim inary Design Phase
141 days
14
Preliminary Design
140 days
15
Lab Demo
140 days
16
Integration and Test Planning
120 days
17
Preliminary Design Review (s)
18
Detailed Design Phase
1 day
Subsystem Detailed Design
257 days
20
Integration and test planning
160 days
21
Critical Des ign Review (s)
Fabricatio n Phase
1 day
Fabrication of Subsystems
300 days
24
I, T, & C Pr oceedures
200 days
25
Operational Softw are Implementation
300 days
26
Integration and Test
Laser Sys tem
100 days
799 days
28
Prelim inary Design Phase
141 days
29
Preliminary Design
140 days
30
Integration and Test Planning
140 days
31
Preliminary Design Review (s)
32
Detailed Design Phase
1 day
12/14
258 days
33
Subsystem Detailed Design
257 days
34
Risk Reduc tion Prototyping
257 days
35
Integration and Test Planning
160 days
36
Critical Des ign Review (s)
Fabricatio n Phase
12/11
400 days
23
27
12/14
258 days
19
22
3/31
44 days
13
37
• Science handover:
3/04
AO Instru m ent Package
261 days
1 day
12/11
400 days
38
Fabrication of Subsystems
300 days
39
I, T, & C Pr oceedures
200 days
40
Operational Softw are Implementation
300 days
41
Integration and Test
100 days
42
System In tegration Phase
201 days
43
System Integration and Test
100 days
44
Commissioning
100 days
45
Science Handover
1 day
Gemini Board
18
Gemini AO Program
MCAO Budget Estimate (Part I)
Program Elem ent
MCAO
Labor Years Labor Cost Subcontract/Materials Total
46.25
4625
7375
12000
Management/System Engineering
4
400
0
400
Analysis and Modeling
3
300
0
300
Laser System
2
200
4280
4480
Management/System Engineering
2
200
0
200
R&D support contingency
0
0
300
300
Laser procurement
0
0
3000
3000
Laser procurement contingency
0
0
980
980
BTO upgrades
0.25
50
50
100
LLT upgrades
0.25
25
25
50
November 15, 1999
Gemini Board
19
Gemini AO Program
MCAO Budget Estimate (Part II)
AO instrument package
30.5
3050
2860
5910
4.5
450
0
450
Mechanical
8
800
150
950
Optics
4
400
450
850
CCD development contingency
0
0
400
400
WFS cameras
0
0
350
350
Deformable and T/T mirrors
0
0
1060
1060
Reconstructor hardw are
0
0
350
350
Other electronics
4
400
100
500
Softw are and controls
6
600
0
600
Integration and test
4
400
0
400
System integration and test
2
200
35
235
Lab Demonstration
2
200
125
325
Optics and mounts
0
0
30
30
Deformable mirrors
0
0
30
50
Phase screens
0
0
30
30
Cameras
0
0
15
15
Control computer and interfaces
0
0
20
20
Integration and experiments
2
200
0
200
2.25
200
0
200
Management/System Engineering
Labor Contingency
November 15, 1999
Gemini Board
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Gemini AO Program
Labor Requirements by Year
Labor Category
1999
2000
2001
2002
2003
2004 Total by Category
AO Project Scientist
AO Project Manager
Administrative Asst
PhD Student/Postdoc
Laser Engineer
Mechanical Engineer
Draftsman
Machinist
Optical Designer/Engineer
Optical Technician
Electrical Engineer
Electronics Tech.
Software Engineer
Labor Contingency
0.31
0.31
0.16
0.06
0.09
1.00
1.00
0.63
0.75
0.88
1.50
0.00
1.00
1.00
0.50
0.38
0.75
0.75
1.00
1.75
0.25
0.75
0.25
0.75
1.50
0.50
1.00
1.00
0.47
0.19
0.50
0.25
0.50
0.50
0.25
0.25
0.25
0.25
0.25
0.50
0.69
0.69
0.13
0.13
0.41
0.25
2.00
0.25
1.00
1.00
0.63
0.75
0.88
2.00
1.00
0.50
1.00
1.00
1.50
0.50
2.00
0.50
0.25
0.25
0.25
0.50
0.25
5.00
5.00
2.50
2.25
3.50
4.75
2.50
2.75
2.50
2.25
3.25
1.75
6.25
2.00
Total by year
0.94
10.00
14.25
11.13
6.16
3.78
46.25
November 15, 1999
1.00
1.00
Gemini Board
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Gemini AO Program
Gemini AO Program:
Division of Work within Partnership
Gemini AO program ambitious, but IGPO is not proceeding alone
•
•
Partnership Workload (including vendors):
– Hokupa’a-85 for Gemini-North: UH
– Hokupa’a-85 for Gemini-South:
• WFS and DM: UH
• Commercially supplied dye laser
– Altair: HIA
– Altair LGS:
• WFS upgrades: HIA
• Laser source: Contract
– Coronograph AO: Instrument supplier
Common infrastructure (IGPO): LGS transfer optics, launch telescope,
and safety system
• MCAO is the focus of IGPO efforts. Significant outsourcing
of work expected after CoDR.
November 15, 1999
Gemini Board
22
Gemini AO Program
Recent Progress
• Overall roadmap to CoDR drafted
– Science requirements, system requirements, system design,
cost, labor, and schedule
• System analysis street map drafted
– LGS power requirements, NGS magnitude limits and sky
coverage, instrument performance, comparison with LGS
• Coordination with Gemini partners and community underway
– HIA (10/23), CfAO (11/2), NOAO (11/4)
– LGS development meeting planned with CfAO for 12/7
– Meeting at Durham (and possibly ATC) planned for 12/9-10
• Launch telescope and transfer optics design in progress
• Conversations with component vendors continue
• System modeling, algorithm development continues
November 15, 1999
Gemini Board
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Gemini AO Program
MCAO—A Step Beyond…
Classical AO
MCAO
• Using the same
components as other
planned LGS AO
systems, MCAO on
Gemini-South will go a
step beyond…
• Enabling NGST-class
observations for the
Gemini Community
November 15, 1999
Gemini Board
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