MUSE opto-mechanical design and performance François Hénaulta, Roland Bacona, Hans Dekkerb, Bernard Delabreb, Slimane Djidela, Jean-Pierre Duboisa, Norbert Hubinb, Blandine Lantza, Wing Lauc, Miska Le Louarnb, Ian Lewisc, Jean-Louis Lizonb, James Lynnc, Luca Pasquinib, Roland Reissb, Martin M. Rothd aCRAL
- Observatoire de Lyon, 9, Avenue Charles André, 69230 Saint-Genis-Laval, France, Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany, cUniversity of Oxford, Astrophysics, Keble Road, Oxford, OX1 3RH, UK, dAIP, An der Sternwarte 16, 14482 Potsdam, Germany bEuropean
INSTRUMENT REQUIREMENTS SCIENTIFIC REQUIREMENTS Angular FoV dimensions Angular sampling Simultaneous spectral range Spectral resolution
Image quality Optical transmission
Nasmyth Platform V L T
1 x 1 arcmin in WFM, 7.5 x 7.5 arcsec in NFM 0.2 arcsec in WFM, 0.025 arcsec in NFM From 0.465 to 0.93 µm 2000 at 0.465 µm 3000 at 0.70 µm (primary wavelength) 4000 at 0.93 µm 80 % of energy within a square of 0.35 arcsec width in WFM, 80 % of energy within a square of 0.056 arcsec width in NFM ≥ 20 % end-to-end (but excluding atmospheric absorption)
MAO
N A R
NGS WFS
WFM
DM & R.O.
O.D.
Main Shutter
WFM
Field Splitter
ICE
NFM
MUSE blockdiagram
VLT INTERFACE REQUIREMENTS Telescope pupil diameter 8m Telescope F/D number 15
NFM
NGS WFS
LGS WFS
‘Direct’ or AO Focal Plane
C.U.
Enlarger
A.D.C.
FO
Structure
Anamorphoser & Relay Optics (R.O.) FO
FOCAL PLANE CHARACTERISTICS Total number of focal planes 24 Pixel number (per focal plane) 4096 x 4096 Pixel/sample 1 along cross-dispersion direction, 2 along dispersion direction Pixel size 15 µm Output F/D number 1.93
X 24 Pseudo-Slit IDS
Subsystems requirements
CCD Focal Plane
IMAGE QUALITY Image Slicer Spectrograph
Fore-Optics Enclosed Energy ≥ 90 %
Enclosed Energy ≥ 85 %
VPHG
Collimator
Image Slicer
SubFoV
IFU
Spectrograph
CCD
Enclosed Energy ≥ 85 %
- in 0.2 " square on-sky
- in 0.2 " square on-sky
- in 0.2 " square on-sky
- in 805 x 1610 µm rectangle
- in 35 x 70 µm rectangle
- in 15 x 30 µm rectangle
(at ISS image plane)
(at focal plane)
(at FO image plane)
Camera
Flatness ≤ 20 µm Peak to Valley
The IFU (Slicer & Spectrograph)
LATERAL STABILITY (RMS on 1 hour dura tion) VLT Nasmyth focus ± 5 µm
Fore-Optics image plane Structure De-rotator ± 20 µm ± 125 µm
Image Slicer slit plane
Sprectrograph focal plane
CCD plane
± 5 µm
± 3 µm
± 1 µm
MUSE overall architecture
FO Tower
Derotator
Calibration Unit
Nasmyth Platform basefloor
IFUs (X 4)
IFUs (X 4)
IFUs Tower baseplate
Relay Optics FieldSplitter
slicer
MUSE Adaptive Optics System
entrance pupil
Nasmyth flange plane
slit lenses row
Nasmyth flange simulator (movable) Calibration Pickup Elements 1 & 2
exit lens
pupil lenses row
input lens
FO baseplate
Relay Optics
IFUs Tower 2
IFUs (X 4)
IFUs (X 4)
IFUs (X 4)
Field-splitter and relay optics
IFUs Tower baseplate
IFUs (X 4)
IFUs Tower 1
IFUs Tower baseplate
IFUs Tower 3
Alignment tools & telescope simulator
≈ 775 mm
7.3mm
MUSE on VLT Nasmyth platform
7.3mm
Pupil stop
Pupil lens
Slit lens
Field stop
Advanced ״catadioptric ״Image Slicer R = 604.63 mm
Optical De-rotator and Enlarger
80.5 mm
1.59 mm
INSTRUMENT PREDICTED THROUGHPUT Worst
Typical MAO
Typical AS
Best
60.4 mm
0.50 0.45 0.40
Throughput
0.35
MUSE CONSORTIUM
0.30
IM AGE QUALITY (W ide Fie ld M ode )
0.25
Enclosed Energy (% )
0.20 0.15
Field of View Centre Interm . Requirem ent = 90 = 90 0.465 µm 96.1 96.6 0.650 µm 94.2 95.1 0.800 µm 92.5 93.6 0.930 µm 92 93
0.10 0.05 0.00 0.465
Fore -Optics
0.500
0.535
0.570
0.605
0.640
0.675
0.710
0.745
Wavelengths (microns)
0.780
0.815
0.850
0.885
0.920
Edge = 90 96.7 95.1 93.6 93
Im a ge Slice r Centre Interm. = 85 = 85 95.1 93.3 92.3 92.6 91 91.1 90.5 90.7
Edge = 85 89.7 92.1 91.7 90.9
Spe ctrogra ph Centre Interm . = 85 = 85 77.6 84.2 94.5 90.7 95.8 94.5 73.7 87
Edge = 85 85.3 89.8 94 77.2
40 mm
