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European
Southern
Observatory
MUSE
Multi Unit Spectroscopic Explorer
AO assisted integral field spectrograph
Developed by a consortium led by:
 CRAL-Lyon (R.Bacon, PI)
Contributions of:
Durham, Leiden, LAOMP, ETH, AIP, ESO
Schedule:
CDR: 2004
Kick off: Jan 2005
Commissioning: 2011
Leiden, April 26th 2005
Page 1
© ESO 2005
AO Department
European
Southern
Observatory
Science objective
3D Ultra Deep Field:
10-19 erg s-1 cm-2
 80x1 hours integration
Faint Ly a emitters; Progenitors of
Milky Way ?
 Star Formation History at Z>4
 Development of dark matter halos
 Link between Lya emitters and High Res. QSO absorption
 Physiscs of high Z galaxies from resolved spectroscopy
 Kinematics, population, cluster, outflows, merger...
 In (nearby) galaxies
 Stars: massive spectroscopy of crowded regions,

Origin of bipolar stellar outflows and shock waves

Leiden, April 26th 2005
SERENDIPITY
Page 2
© ESO 2005
AO Department
European
Southern
Observatory
MUSE Requirements




Spectrometer resolution R~3000
Wavelength range: 0.465μm-0.93 μm
300 x 300 spatial resolution elements (spaxels)
High efficiency
 Shutter open time
 Throughput, > 0.24
 2 observing modes: Wide Field Mode and Narrow Field Mode
Observing mode
WFM (GLAO)
NFM (LTAO)
1’x1’
7.5”x7.5”
Spatial Sampling
0.2x0.2 arcsec^2
25x25mas^2
Spatial resolution
0.3-0.4 arcsec.
30-50 mas
AO “performance”
2 x EE increase @
750nm
Strehl 0.05 (0.1) @ 650nm
70% @ Gal. pole
TT reference: Science object
70%-ile
-
FoV
Sky coverage:
AO “on time”
Leiden, April 26th 2005
Page 3
© ESO 2005
AO Department
European
Southern
Observatory
MUSE Instrument concept
MCAO
focal plane
Enlarger/
Anamorphoser
Dispersing element
CCD
plane
Camera
Collimator
Field-splitter
Split focal
plane
Spectrometer
pseudoentrance slit
Sub-FoV
Image slicer
Spectrometer
24 Spectrometers IFUs
4k x 4k Detectors
402.653.184 pixel
Leiden, April 26th 2005
Page 4
© ESO 2005
AO Department
European
Southern
Observatory
MUSE Facility
 VLT-Nasmyth
platform size:
5mx4m
 Max load:
8.000Kg
Leiden, April 26th 2005
© I. Lewis,
Page 5 Oxford
© ESO 2005
AO Department
European
Southern
Observatory
GALACSI
Ground Atmospheric Layer Adaptive
Corrector for Spectroscopic Imaging
 Located Nasmyth focus of UT4
 Developed and build by ESO AO dept.
 4 Na-LGS, 1’(WFM) and 15”(NFM) off axis
 1 NGStar within 45”<r<120” (WFM) > 17.5mag (R)
 1 NGSsource (extended) on axis >15mag (goal 16mag J-K
band)
 Baseline: VLT-Deformable M2 is the DM
 Test bed (incl. M2 ?) developed and build by Leiden
Leiden, April 26th 2005
Page 6
© ESO 2005
AO Department
European
Southern
Observatory
GLACSI Requirements
 Transmission: 92% average, 80% minimum (WFM)
 AO operations in 70%-ile of the atmospheric conditions at 30° off zenith
  0.6” to 1.1” seeing @ 500nm
 Light pollution of science field:
 @ 589nm ±20nm (goal 10nm) < brightest sky line, e.g. <600 photons/s/sq”
 Outside the Na notch<10ph/Angstrom/hour/sq arc sec.
 “No” NGS within the Science field, scattered light!
 Sky coverage > 70% at the galactic pole
 Long integration time (80x1h)
 High temporal instrument stability
 AO residual Image motion <50mas within 1h (WFM) TBC
 AO residual Image motion <10mas within 1h (NFM) TBC
 AO Setup time < 5 min
Leiden, April 26th 2005
Page 7
© ESO 2005
AO Department
GALACSI Optical layout (WFM)
European
Southern
Observatory
LGS
WFS
LGS pick up
Exchangeable unit for NFM
Field separator
FIELD SEPARATOR
Transmits 589nm
Reflects visible light
1’ Optics free
Scientific Field
1.45 arc min
Leiden, April 26th 2005
CALIBRATION
MIRROR
Reimaging lens
F/4.0
4 arc min
180mm defocused
Laser beam
Hole
4’ Field
selector
LGS
WFS
LGS Focus
compensation
Page 8
Nasmyth Adaptor flange
500 mm BFD
Visible
TT
Sensor
© ESO 2005
AO Department
European
Southern
Observatory
Functional requirements
 Matching between SH WFS and DSM
 co rotate to the pupil
 LGS mounted to the telescope
 Field rotation with the speed of the pupil rotation
 GALACSI needs to co-rotate to the pupil
 At Nasmyth the pupil rotation is equal to the altitude motion of
the telescope
  operational range: 0° to 60° Zenith distance
 Most probable case: 5° to 45°, e.g. ± 20° instrument motion P-V
 Low rate, < 15°/hour
 Helps to achieve the image stability requirement
 NGS rotates with the field
  Field selector (rotating with the pupil) needs to follow the field
rotation - pupil rotation (WFM)
Leiden, April 26th 2005
Page 9
© ESO 2005
AO Department
European
Southern
Observatory
 GALACSI is mounted to
the Nasmyth rotator
 Muse is on the
Nasmyth Platform
 Field de-rotation for
Muse
 Problem:
Field splitter
De-rotator…
GALACSI
GLAO/SCAO
VLY-Nasmyth rotator
GALACSI-MUSE Instrument





Rotator wobble
Platform wobble
Flexure of GALACSI
Temperature effects
Residual alignment
errors,
 Field de rotator
wobble
 …
MUSE
Spectrographs
Causes differential image
motion between the
GALACSI and MUSE
Instrument
  metrology is required
Nasmith platform
Leiden, April 26th 2005
Page 10
© ESO 2005
AO Department
CCD
field
European
Southern
Observatory
Metrology
LGS
WFS
4’ Field
selector
MUSE
focal plane
Nasmyth Adaptor flange
CCD camera
focal plane
Reimaging lens
Point source mounted
at MUSE focal
De-rotator
F/4.0
Lateral
motion field
of Muse, the de-rotator
plane MUSE
or
GALACSY
measured
and
4 sources on MUSE
imaged
to acan
CCDbecamera
inside
field
Visible
corrected
the NGS Averaging
Field
of 4 centroids
gives the
GALACSI by offsetting
TT
4 Point
LGS Focus
LGS free”
Sensor
selector.
“rotation
position
of the field center
de-rotator moves
spot
on
the
CCD
compensation
sources
Leiden, April 26th 2005
WFS
Page 11
© ESO 2005
AO Department
Opto-mechanical implementation
Leiden, April 26th 2005
Page 12
© ESO 2005
European
Southern
Observatory
AO Department
4 LGS WFSs
32x32 subap.
240x240 L3 CCD
4 LGS pick up
Mirrors
for WFM/NFM
AO Calibration
sources
European
Southern
Observatory
Field Selector Assembly
(turntable + goniometer stage)
Field Splitter
Calibration/acquisition mirror
Beam from the telescope
Acquisition
CDD camera
IR T/T sensor
Metrology
pick up mirror
Metrology
CCD camera
VIS T/T sensor
240x240 L3 CCD
Leiden, April 26th 2005
Page 13
© ESO 2005
AO Department
European
Southern
Observatory
Leiden, April 26th 2005
Page 14
© ESO 2005
AO Department
European
Southern
Observatory
Field Selector Tracking
 Field selector field: Diameter 4 arc min with 1.45 arc min hole
 NGS moves on a circular trace
 Speed: Field rotation + Pupil rotation
 Worst case: Meridian crossing close to zenith
(180° rotation within 2 minutes  2mm/s)
 Tracking accuracy >> Image stability
  ~15μm position accuracy during the motion in the entire field
 Offset requests from the Metrology
4 arc min
Visible Tip Tilt
Sensor Field of View
Hole
1.45 arc min
Leiden, April 26th 2005
Page 15
© ESO 2005
AO Department
European
Southern
Observatory
LGS light pollution
Science field
 Small if the LGSs are launched at the side of the telescope
 Severe if launched from M2:
6
LGS,
LGS,pointing:60",
pointing:60",z=30
z=15
z=60
z=45
z=0
x 10
100
1 LGS 330" off axis,
 Background:
~ 10e7 photons/s/sqarcsec.
7.5 1 LGS 330" off axis,
7.5
400
 Permitted
background
in
the
science
field
after
a
Notch
filter
80
8.5
10
20
6.5
600 Photons/s/sqarcsec.
300
60
7
Notch
filter with attenuation ~ 5e5 required 15
7
8
field position ["]
0
0
-100
-20
6
6
-200
-40
5
5
6.5
8
7
0
4
4
5.5
6
3
-5
7
6.5
6
-10
5.5
5
6
6
-15
-300
5
6
7.5
6.5
100
field position ["]
field position ["]
10
20
7
9
200
40
7
3
2
-60
1
5.5
5.5
5
-20
-400
-80
5
4.5
-300
-400
-100
-100
-80
Leiden, April 26th 2005
-60
-40
-20
0
20
field position ["]
40
60
-200
80
100
0
-100
320
325
field position ["] 5
300
200
330
335
field position ["]
400
340
0
345
350
2
1
0
100
Page 16
© ESO 2005
AO Department
European
Southern
Observatory
Fratricide effect
Simulated for large
field
WFS cut a fraction
of the field
4 LGS
Launch beh. M2
Pointing 60“ off
axis
Sub aperture
position (0, -1) [m]
View of 1 subap. "Big WFS"
80
60
WFS
40
WFS #2
field position ["]
 Not present if 20the LGSs are
launched at the side of the
telescope
0
  but Spot elongation!
WFS #3
-20
 Severe if launched
from M2:
 Some sub apertures “look
trough” the-40launch beam of
one of the lasers and are
completely-60blinded
 How many and in which
-80
conditions as
well as the
Impact to WF reconstruction
-80
-60
-40
is to be analyzed
Leiden, April 26th 2005
WFS #1
WFS #4
-20
0
20
field position ["]
40
Page 17
60
80
© ESO 2005
AO Department
VME64x
Statistics
CPU
CPU
192x192 ac tive area
CPU
LCU
100/1000
Ethernet
CPU
CPU
CCD Controller
CPU
256x256 detector
CPU
CPU
CPU
192x192 ac tive area
CPU
CPU
CPU
CPU
CCD Controller
CPU
256x256 detector
CPU
CPU
CPU
CPU
192x192 ac tive area
CPU
CPU
CPU
CPU
CCD Controller
CPU
CPU
 MUSE RTC
architecture based
on ESO RTC
platform (SPARTA)
 FPGA for slope
calculation (pipeline)
 G4 processor
boards for the
reconstruction on
VME bus
CPU
CPU
CPU
European
Southern
Observatory
Reconstruction
RTC
256x256 detector
CPU
256x256 detector
CPU
CPU
CPU
CPU
CCD Controller
CPU
CPU
CPU
Front-End
Acquisition
Leiden, April 26th 2005
Tip/Tilt Sensor
Page 18
© ESO 2005
Control
CPU
192x192 ac tive area
Deformable
Mirror
AO
Department
European
Southern
Observatory
GALACSI Schedule
CDR: Mar.2004
Trade off review: Oct. 2005
Interface definition
LGS launch position
DSM feasibility / approval
PDR: July 06
FDR: July 07
Integration and testing stand alone/
with DSM
GALACSI PAE: March 2010
GALACSI Commissioning: Oct. 2010
Leiden, April 26th 2005
Page 19
© ESO 2005
AO Department