PILOT: Pathfinder for an International Large Optical Telescope -performance specifications - PowerPoint PPT Presentation

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PILOT: Pathfinder for an International Large Optical Telescope -performance specifications

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Title: PILOT: Pathfinder for an International Large Optical Telescope -performance specifications


1
PILOTPathfinder for an International Large
OpticalTelescope-performance specifications
Jon Lawrence
JACARA Science Meeting PILOT Friday March
26 Anglo Australian Observatory
2
The data
DOME C
South Pole
  • Turbulence
  • SODAR (winter 2003/4)
  • MASS (winter 2004)
  • DIMM (summer 2003/04)
  • Sky temperature and opacity
  • SUMMIT (winter 2003/4)
  • MIR FTI (summer 2003/4)
  • Met data
  • COBBER (winter 2003/4)
  • ICECAM (summer 2003/4)
  • AWS (winter 2004)
  • met balloons (summer 2000-04)
  • Turbulence
  • SODAR (winter 2000/1)
  • DIMM (winter 2000/01)
  • microthermals (winter 1996)
  • Sky temperature and opacity
  • SUMMIT (winter 2003/4)
  • MIR FTI (summer 2002/3)
  • MISM (winter 1998)
  • NISM (winter 2000)
  • Met data
  • AWS
  • met balloons

3
Seeing Data Dome C - 2002/3
DIMM summer 2002 median seeing 1.2
arcsec (Aristidi et al, 2003) SODAR summer/
winter 2003 median seeing 0.08 arcsec (33
floor 0.05)
4
Seeing Data Dome C - 2003/4
  • DIMM summer 2003/4
  • data not yet reduced
  • median seeing lt 1.1 arcsec (0.4-0.7 arcsec)
  • isoplanatic angle 10 arcsec

5
CN2 profile Dome C Bad
?iso 9.5 arcsec fG 30 Hz
?iso 13.5 arcsec fG 7 Hz
r0 0.05 m (1.8 arcsec seeing)
r0 0.2 m (0.5 arcsec seeing)
6
CN2 profile Dome C Good
?iso 9.5 arcsec fG 30 Hz
?iso 13.5 arcsec fG 7 Hz
?iso 30 arcsec fG 2Hz
r0 0.05 m (1.8 arcsec seeing)
r0 0.2 m (0.5 arcsec seeing)
r0 0.7 m (0.15 arcsec seeing)
7
CN2 profile Mauna Kea
?iso 9.5 arcsec fG 30 Hz
?iso 13.5 arcsec fG 7 Hz
?iso 30 arcsec fG 2Hz
?iso 2 arcsec fG 50 Hz
r0 0.05 m (1.8 arcsec seeing)
r0 0.2 m (0.50 arcsec seeing)
r0 0.7 m (0.15 arcsec seeing)
r0 0.20 m (0.50 arcsec seeing)
8
Atmospheric parameters
seeing (arcsec) isoplanatic angle Greenwood
(arcsec) Frequency (Hz) Mauna Kea 0.50
2-3 50 Dome C 0.15 - 0.50 10-30 2-10
9
Atmospheric parameters
seeing (arcsec) isoplanatic angle Greenwood
(arcsec) Frequency (Hz) Mauna Kea 0.50
2-3 50 Dome C 0.15 - 0.50 10-30 2-10
?
?
10
Adaptive Optics
object
guide star
to tip-tilt secondary
tip-tilt control
telescope optics
centroid sensor
dichroic beam splitters
deformable mirror
image camera
wavefront control
wavefront sensor
wavefront analysis
11
PILOT AO systems
  • Tip-tilt
  • tip-tilt mirror quad sensor
  • Low Order AO
  • ds0.3 (30-50 actuators)
  • High Order AO
  • ds0.08 (500-1000 actuators)

12
PILOT AO system performance
  • Low Greenwood frequency
  • lower feedback loop frequency
  • higher integration time
  • fainter stars
  • lower SNR/bandwidth errors
  • Large isoplanatic angle
  • larger fields
  • brighter stars
  • low anisoplanatic error
  • Better seeing (lower r0)
  • less actuators
  • lower fitting error

13
Strehl ratio - V band
On-axis low order
DCG
DCB
MK
14
Strehl Ratio
15
Strehl ratio - K band (tip-tilt correction)
Off-axis
On-axis
DCG
DCG
DCB
DCB
16
Uncomp DCB
Uncomp DCG
Diff lim 2m
17
Uncomp DCB
Uncomp DCG
DCB off-axis
DCG off-axis
Diff lim 2m
on-axis
18
Uncomp DCB
Uncomp MK
Uncomp DCG
DCB off-axis
DCG off-axis
Gemini altair
Diff lim 8 m
Diff lim 2m
on-axis
19
(No Transcript)
20
Sky emission
MK
Emission 5 _at_ 0 C
21
Sky emission
SP
Emission 5 _at_ -63 C
22
Sky emission
DC
Emission 5 _at_ -66 C
23
Sky Transmission - NIR/MIR
MK
24
Sky Transmission - NIR/MIR
DC
25
Relative integration time MK versus SP, DC, DA
26
Relative integration time 8m MK versus 2 m DC
PILOT
diffraction limit
27
Relative integration time 8m MK versus 2 m DC
PILOT
Seeing limit - extended object
28
Relative integration time 8m MK versus 2 m DC
PILOT
Seeing limit - extended object
29
Possible PILOT Instruments
Visible (AO-on) imaging ? 4k array (0.03
arcsec/pixel) 2.3 arcmin FOV NIR wide field
imaging JHK bands ? 4k array (0.6
arcsec/pixel) 10 arcmin FOV DF imaging KLM
bands ? 1k array (0.23 arcsec/pixel) 4
arcmin FOV MIR imaging N band ? 0.5k array
(0.7 arcsec/pixel) 6 arcmin FOV
30
V band imaging - AO on
Point source
ext object
31
Point source
K band imaging - tip tilt
ext object
32
Point source
N band imaging
ext object
33
Summary
  • Visible AO system (40-100 actuators plus
    tip-tilt)
  • near diff lim for on-axis stars 8-12 mag
  • off-axis reasonable performance up to 1-2 arcmin
  • highest ground based resolution!!
  • mirror figure error is very important lt 50 nm rms
    required
  • spectroscopy?
  • Near Infrared K band imaging
  • tip-tilt correction is enough for near diff lim
    (0.2-0.3 arcsec)
  • equivalent to 8m ML telescope for extended
    object, 5m for point source
  • wide field or narrow field science?
  • Mid-Infrared imaging
  • niche is wide field sensitivity
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