Download Diapositiva 1 - tls

Nahual at first glance.
Nahual is an echelle high resolution spectrograph driven by RV
science programs. High stability and reliable operation is obtained
minimizing mechanisms and in a cryogenic environment.
It basic mode will allow seeing limited operation for reliability.
Nahual will be moved behind the telescope AO system once is fully
operational.
FOLDER MIRROR
ECHELLE
GRATING TURRET
Intermediate focal plane
CRYOSTAT
ENTRANCE
CALIBRATION
GAS CELL
Off axis parabola
Off axis
parabola
CROSS DISPERSION
UNIT
FOCAL PLANE
WHEEL.
-ADC
-IMAGE SLICER
-SLIT
APERTURES
Detector
CAMERA
(Three Mirrors+ Corrector)
Nahual at first glance.
PERFORMANCE HIGHLIGHTS
Science Modes. Supplied with the grating turret.
•High resolution 1. Grating 32.2 lin/mm at 63º (R=41582). Almost complete J,H and K coverage.
•High resolution 2. Grating 41.6 lin/mm at 76º (R=84969). Partial J,H and K coverage.
•High resolution 3. Grating 31.6 lin/mm at 76º (R=84969). Partial J,H and K coverage.
•Low resolution mode. Flat mirror instead of echelle. J (R=1500), H (1000) and K (500).
•Spectral performance
• 80% of the incident light from the slit on the
detector in two pixels.
• Resolution element. Two pixels
• Peak efficiencies for the HR mode 42%
• Mean efficiencies for the LR mode 53%
•These efficiencies are without the detector
•Focal plane aperture.
•For the seeing limited mode 0.525”x0.6125”
•For the AO mode 0.175”x 1.84” arc sec
•Other main characteristics
•Plate scale 0.175” arc sec/pixel
•Atmospheric Dispersor Corrector unit
•Calibration Gas Cell unit
•Image slicer for seeing limited mode
•IR slit viewing unit for pointing
Nahual Optical Design
3rd NAHUAL meeting
Dornburg/Saale
GTC TELESCOPE
NAHUAL
Ernesto Sánchez-Blanco
Eduardo Martín
Eike Guenther
Summary
•Introduction
•Requirements
•Baseline optical design
-Optical subsystems and performances
-Atmospheric dispersor corrector trade off.
-Cross dispersion unit trade off
•Nahual Upgrade study
•Optical Management
•Current phase. Scope and schedule
•Next phase. Scope and schedule
•Update to optics cost
•Work in progress
INTRODUCTION
 Nahual evolution path.
Current Design for first light.
IAC 2006
Improving image quality
Double Pass Cross Dispersion
(Two prisms)
2Kx2K detector
F3.5 Camera
First Design. Tauttenburg 2005
Single Pass Cross Dispersion
2Kx2K detector
F3.5 Camera
 Nahual baseline design will start
operation in a seeing limited scenario
Untill the GTC-AO system is available.
Nahual Upgrade for AO operation.
Double Pass Cross Dispersion
(could be increased: Three prisms)
Change to 4Kx4K detector (Not a gain)
Change to F7 Camera (Not a gain)
REQUIREMENTS I
 Maximize flux entrance for seeing limited operation. Minimum
0.525”x0.525”. (current design allows a 0.525”x0.6175” aperture)
 Maximize spectral stability (minimize mechanisms).
 Spectral range: J,H and K bands (goal to include Y band)
 Resolution: Above 40000 (goal 75000).
K BAND
H BAND
4Kx4K
Detector
2.4002 MICRONS
2.3275 MICRONS
1.9695 MICRONS
1.8290 MICRONS
1.7865 MICRONS
1.4770 MICRONS
1.3965 MICRONS
1.3715 MICRONS
J BAND
1.129 MICRONS
REQUIREMENTS II
Optimize detector. (use 2 pixels per spectral resolution element)
Plate scale at detector 0.175” arc second per resolution element
(2 pixels).
The telescope provides a F#15.6 (circumscribed pupil, or F17
in inscribed pupil.
2Kx2K HgCdTe Hawaii Detector with 18 micron pixels.
Nominal spectral resolution performance without AO system.
BASELINE OPTICAL DESIGN
FUNCTIONAL CONCEPT: white pupil
FIRST STAGE: HIGH DISPERSION
FP1
SECOND STAGE: CROSS DISPERSION
FP2
ECHELLE
FP3
CROSS DISP
CAM
OAP1
OAP2
FP: Focal plane
OAP: Off axis parabola
FLD: Folder mirror
FLD1
OAP3
BASELINE OPTICAL DESIGN:
CURRENT DESIGN LAYOUT
FLD1
FP2
ECHELLE
TURRET
OAP1, OAP2
CRYOSTAT
ENTRANCE
FP1
OAP3
CROSS DISP
FP3
FP: Focal plane
OAP: Off axis parabola
FLD: Folder mirror
CAM
(Three Mirrors+ Corrector)
P
BASELINE OPTICAL DESIGN:
DESIGN SUMMARY I
For GTC Nasmyth platform.
F15.6 beam from telescope, seeing limited or AO corrected
•PRE-FOCAL PLANE
Atmospheric Dispersor Corrector
Image slicer
Gas cell calibration unit
•AUXILIARY SUBSISTEMS
IR guiding unit for object pointing and tracking
Telescope A&G unit for VIS pointing.
Telescope Instrument calibration module for spectral flat field
and low Res spectroscopy .
BASELINE OPTICAL DESIGN:
DESIGN SUMMARY II
SPECTROGRAPH
 The spectral resolution element is in two pixels.





Collimator/Echelle pupil/Camera
Focal length 1700mm.
Off axis parabola, F# 15.6.
Estimated transmission 97% (without echelle).
Echelle Pupil
Size 109 mm
Standard echelle sizes are 128mmx254mm and 204mmx410mm
depending on the grating (blazed at 63º or 76º).
Folder mirror/Second stage collimator
 Focal length 1700mm
 Refractive, F# 15.6.
 Estimated transmission 97%
BASELINE OPTICAL DESIGN:
DESIGN SUMMARY II
Cross dispersion/white pupil
 Double pass design. Needs a mirror.
 Can accommodate up to three prisms.
 Estimated transmission 83%





Camera
Focal length 381.4mm (F#=3.5)
Three mirrors, one spherical and two aspherics. One lens as corrector
Estimated transmission 91%
Mechanisms within the cryostat
Focal plane wheel with fixed positions.
Echelle wheel, with a position for each grating plus one mirror (4
positions).
BASELINE OPTICAL DESIGN:
PERFORMANCE SUMMARY




Science modes.
High resolution 1 (41000). Almost complete J,H and K coverage.
High resolution 2 (85000). Partial J,H and K coverage.
High resolution 3 (85000). Partial J,H and K coverage.
Low resolution mode. J (R=1500), H (1000) and K (500).
Image quality

80% of the energy arriving at the detector from the slit will fall on two pixels.
 Transmission (rough estimation)
 42% for the first light design
SUBSYSTEM
TRANSMISSION (HR mode)
GAS CELL (4 air-glass interfaces)
0.922
ADC (6 air-glass interfaces)
0.886
IMAGE SLICER (To be designed)
0.922*
MAIN OPTICS, 4 reflections (no
camera)
0.94
ECHELLE GRATING (peak efficiency)
0.8
CROSS DISPERSION UNIT (3 air
glass-1 mirror)
0.83
CAMERA
0.91
TOTAL
0.427
ATMOSPHERIC DISPERSOR CORRECTOR UNIT I.
•The ADC unit shall correct the differential atmospheric refraction effect for the
J,H and K bands.
Angle from Zenith in
degrees
J BAND position in
arc seconds
H BAND (1.6
microns) position in
arc seconds
K BAND (2.2
microns) position in
arc seconds
0
0
0
0
15
0
0.0100
0.0200
30
0
0.0250
0.0430
40
0
0.0360
0.0620
50
0
0.0510
0.0880
55
0
0.0610
0.1060
60
0
0.0740
0.1280
65
0
0.0910
0.1580
70
0
0.1170
0.2020
75
0
0.1570
0.2730
80
0
0.2350
0.4080
82
0
0.2900
0.5030
84
0
0.3750
0.6510
86
0
0.5220
0.9070
•Top. Refraction dispersion
at 81º of elevation
•Left. Refraction effect for
•different elevations
ATMOSPHERIC DISPERSOR CORRECTOR UNIT II.
•Requirements: The image on the entrance slit will not have chromatic
•aberrations larger than 0.06” arc seconds to allow the observation of
•double or multiple science targets from zenith of 50º.
Atmospheric refraction for H and K bands relative to J band
J band
H band
K band
0.9
0.8
0.7
Arc seconds
0.6
0.5
0.4
0.3
0.2
0.1
0
-0.1
0
10
20
30
40
50
Elevation
60
70
80
90
•Trade Off analysis was done regarding the following criteria.
•Adjustable unit (one mechanism required).
•Fixed unit (an error of correction in requirements within an elevation range.
•Three designs were worked (two warm and one cold).
ATMOSPHERIC DISPERSOR CORRECTOR UNIT III.
•Adjustable versus fixed unit.
•Mechanism issues.
•Emissivity for continuous units
Photon flux contributions
12000
11000
Sky background
Sky+Telescope
Sky+Telescope+warm ADC
10000
Photons/nm*seg arc*seg
9000
8000
7000
6000
5000
4000
3000
Photon flux per nanometer per second
per squared arc second at the instrument focal plane
Telescope emissivity=0.1
ADC emissivity=0.15
Sky emissivity at K=0.134 at 230Kelvin
2000
1000
1.5
1.6
1.7
1.8
1.9
2
Lambda
2.1
2.2
2.3
2.4
2.5
•The preference of the trade Off result is to have a fixed cold ADC removable
unit in the focal plane wheel.
ATMOSPHERIC DISPERSOR CORRECTOR UNIT IV.
•Proposed concept.
• Cold within the cryostat.
•To be assembled in a cylinder 25mmx25mm at the focal plane wheel.
ATMOSPHERIC DISPERSOR CORRECTOR UNIT IV.
•ADC Performance.
•From 0º to 21º no ADC in the optical path.
•Start operation at 21º of elevation. Insert ADC.
•End of the correction range within requirement 51º.
•ADC Performance at 21º (left), 39º (center) and 51º (right).
•The circle is the airy pattern at 1.5 microns (50 microns diameter)
• Extreme wavelengths are 1.13 and 2.42 (J and K band edges).
ECHELLE DISPERSION UNIT. High Res mode.
Spectral coverage I
•Three gratings with fixed positions are considered plus a mirror for low
• resolution (cross dispersion) spectroscopy.
•One grating at R=41000
•Two gratings at R=85000
ECHELLE DISPERSION UNIT. Spectral coverage II
(d / n)  (sin(  )  sin(  ))  
a=63º (at litrow)
b=+-2.76º are the edges of the detector
d=23.2-1 mm/lin grating lines per milimeter
n= diffraction order.
ECHELLE DISPERSION UNIT. Spectral coverage III
Efficiency through the field for a single
order
•On the top wavelenght coverages
•On the left experimental results for
grating 23.2 lin/mm at order 39 (K band)
•Peak efficiency 80% (variable with order).
ECHELLE DISPERSION UNIT. Spectral coverage IV
•Bottom: Relative envelopes
for different orders normalized
at the peak.
Out of blaze efficiency envelope grating 23.2 lin/mm @63º
1
0.9
•Top: efficiency at J band in
Order 80.
As we move to higher orders
The peak efficiency decrease
Relative efficiency from blaze
0.8
0.7
Order 32 envelope
from 2369nm to 2428
0.6
0.5
Order 70 envelope
from 1083nm to 1110 nm
0.4
•Quotation: Zerodur gold coated
• 63º blazed (128mmx254mm)
48.200 euros
• 76º blazed (204mmx410mm)
79.500 euros
0.3
0.2
0.1
0
-3
-2
-1
0
1
Departure angle from blaze
2
3
CROSS DISPERSION UNIT I. Trade Off analysis
Required spectral dispersion
• 18+2 pixels between the closest adjacent orders (32-33 of K band).
• This allows a minimum point source FOV of 0.525”x0.525” arc seconds
• 7 options were analyzed, in single, double pass, symmetrical and
non symmetrical prisms.
CROSS DISPERSION UNIT Trade Off summary.
COMPARATIVE DESIGN CHART
Blank number
(22000 eu
price/blank)
Prism number
(10000 *price/
prism)
In double pass
mirror 6000 eu
mirror included
17.04
3
Double pass
asymmetric
2 prisms
17.73
Single pass 4
prisms
Total price
(euros)
Pixels
between
J- 1.129
K- 2.400
microns
Average Transmission
0.985 air/glass
0.99 absorp./prism
(0,99 mirror used)
3
96000
891
88%
1
2
48000
970
84%
22.17
4
4
128000
1174
85%
Double pass
asymmetric
3 prisms
22.77
2
3
80000
1333
77%
Double pass
symmetric
2 prisms
23.61
2
2
70000
1255
84%
Double pass
asymmetric
4 prisms
32.2
2
4
94000
Vigt-
71%
Double pass
symmetric
3 prisms
36.8
3
3
102000
2047
77%
Cross Dispersion
Power between
orders 32 and 33
(in pixels)
Single pass
3 prisms
Design type
(Prism number)
CROSS DISPERSION UNIT
Trade Off summary. Analyzed Options
CROSS DISPERSION
Trade Off summary.
CROSS DISPERSION UNIT II
Benefits of the double pass design
• Twice the dispersion of single pass (with the same number
of prisms)
• Better AIV process
• Upgradeable number of prisms and more room available
Two ZnSe prisms and a mirror
Or two prisms, with one silvered side.
Problems of the double pass design
• Slightly larger mirrors in the camera
• A light astigmatism is introduced because the
path is not exactly symmetric.
CROSS DISPERSION UNIT III
•23 pixels between the orders 32 and 33 allowing a 0.61”x0.525” FOV with
two pixels left dark before starting with the next order
Two prisms double pass coverage
CROSS DISPERSION UNIT IV
Quotations:
•Per ZnSe prism blank: 22.400 EU/blank
•Per ZnSe prism manufacture and coating: 15.000 EU/piece
LOW RESOLUTION MODE. Spectral coverage I
•Select the mirror instead of the echelles
in the grating turret.
•Dispersion is due to the ZnSe prisms.
2.4 MICRON
2.3 MICRON
1.9 MICRON
1.8 MICRON
1.5 MICRON
1.4 MICRON
1.25 MICRON
1.2 MICRON
1.05 MICRON
1 MICRON
•Bottom: Spot diagram of the
dispersion due to the ZnSe
Prisms alone.
LOW RESOLUTION MODE. Spectral resolution
•Bottom: Resolution considering an aperture of 0.175” (two pixels).
•The current satandard aperture is 0.612” (7 pixels) wide. For optimum
performance a new aperture/slicer would be required for this mode.
•Resolution summary
•(2 pixels)
•J band 1500
•H band 1000
•K band 500
Nahual Low Resolution mode performance
2500
Resolution (two pixels)
2000
1500
1000
500
0
1
1.2
1.4
1.6
1.8
Lambda in microns
2
2.2
2.4 2.5
LOW RESOLUTION MODE. Image quality
•Within requirements for the full J, H and K bands.
•Significant degradation out of these bands
•Image quality
•(Box is 2 pixels wide)
• Circles are Airy disk
•On Top the wavelengths
CAMERA.
Off axis aspherical.
Centered sphere.
ZnSe corrector.
Spherical surfaces
80mm diameter
25mm thickness
Off axis aspherical.
CAMERA. Mirror size
M1:280x 220
•Maximum size did not increase
relative to the original design.
•No vignetting in J,H and K.
•Light vignetting out of these bands
Quotations:
•Pending contacts with manufacturers
M2:180x 150
M3:280x 220
IMAGE QUALITY I.
H BAND
J BAND
K BAND
•Good unvignetted image quality in
J,H and K bands (two prisms double pass)
• Worse image in I band. To be optimized
in the next iteration.
IMAGE QUALITY II.
K BAND
Box size is 2 pixelsx2 pixels
Circle: Airy disk
EER 80%=16.2 microns
K BAND
EER 80%=15.6 microns
EER 80%=16.9 microns
Slit image in the K band
1.4
IMAGE QUALITY II.
Enclosed energy in two pixels
1.2
K BAND
1
80% at 19.2 microns
Relative flux
1
0.9
J band slit at 1.1679
microns.
0.8
0.7
0.8
76% at 18 microns
0.6
0.4
0.6
0.2
0.5
80% at 17.5 microns
side
0.4
0
-100
-80
-60
-40
81% ay 18 microns
0.3
-20
0
20
40
Microns from centered slit
60
80
100
Slit image in the H band
1.4
0.2
H Band
1.2
0.1
1
-80
-60
-40
-20
0
20
40
60
80
100
•Convoluted slit with the psf
(geometrical + diffraction).
•J and H bands over 80% in two pixels
•K band 76% EES in two pixels
80% at 17.3 microns
Relative flux
0
-100
0.8
83% at 18 microns
0.6
0.4
0.2
0
-100
-80
-60
-40
-20
0
20
Microns from centered slit
40
60
80
100
UPGRADE PATH
GTCAO
NAHUAL
ADC
GTC CASSEGRAIN FOCUS
K SYSTEM
DERROTATOR
DM MIRROR
NAHUAL
GTC ADAPTIVE
OPTICS CORRECTOR
UPGRADE PATH
•NAHUAL WILL BE READY TO BE USED WITH AO GAINING S/N
AND SPATIAL RESOLUTION AS SOON AS THE TELESCOPE AO IS
AVAILABLE.
We can remove Nahual ADC.
Changing the image slicer by a single “long slit” (0.175”x 1.837”).
We leave room to allocate a third prism in the cross dispersion unit.
•EXPECTED PERFORMANCES ARE STILL TO BE EVALUATED
The single object will cover an area about (0.175”x0.175”) against
the 0.525”x0.615” of the seeing limited aperture. This is a factor 5
regarding S/N gain due to sky background.
•BUT…
The AO system will loose light through its path (83% transmission).
The AO system is warm, so at the K band an increase of emissivity
(around 0.25) for the full system is expected.
So the final increase in s/n will be lower (probably a factor 2 or 3).
UPGRADE PATH
•RESULTS OF THE ANALISYS OF UPGRADING WITH A NEW
DETECTOR AND CAMERA. ¿WHY IS NOT USEFULL?
Original idea was to use the grating of R=40000 at double resolution
changing the detector in a 4Kx4K, doubling the camera focal length
and reducing the slit aperture to half the current one (to 88 mas).
F7 CAMERA
4KX4K DETECTOR
Design originally done to consider future envelopes needs
UPGRADE PATH
•All the concept is right considering we are able to maintain the
spectral resolution element (the image of the slit) in two pixels.
•But that is the problem. The diffraction of the spot at K band does not
allow to put all the light in two pixels. Increasing the camera focal
length has to be discarded.
First Light Design. F3.5 camera
Upgraded Design. F7 camera
Boxes are 2 pixels wide. The slit is projected geometrically in a bit less than two pixels.
Circles are the Airy disks at the shown wavelengths (K band edge).
UPGRADE PATH
Real^2= Slit Projection^2+ Psf aberration^2+diffraction^2
With the current camera, the heaviest contribution is that of the Slit
projection. Real=41 microns for 36 microns in two pixels.
•31 microns, is the geometrical projection of 175 mas slit on the detector.
•18 microns, are the geometrical aberrations (in 1 pixel aprox).
•20.5 microns is the Airy disk diameter. (K band edge)
But if we reduce the slit to 88mas, and double the camera focal lenght twice
to sample this aperture with two pixels, the values will be Real=54 microns.
These are exactly 3 pixels.
•31 microns, is the geometrical projection of 88 mas slit on the detector.
(half slit but double camera focal lenght)
•18 microns, are the geometrical aberrations (in 1 pixel aprox). (this is a
reasonable value we could obtain in a more optimized design)
•41 microns is the Airy disk diameter. (the Airy is doubled in size on the
detector, because we doubled the camera focal lenght)
UPGRADE PATH
CONCLUSIONS
•Upgrading with a longer focal length camera results in a limited performance.
•Upgrading just with a detector has the following problems.
•Severe vignetting could be unavoidable with the current anastigmatic
design.
•Large marginal angles (twice the current ones) will be responsible of low
diffraction efficiencies in a single order within the new detector area.
•Considering the cost of this upgrade with the benefits, it seems not to be worth
doing them.
OPTICAL MANAGEMENT: CONCEPTUAL DESIGN
PHASE
•Schedule September 2005-September 2006
•Resources: 360h for optical design
•SCOPE for the conceptual optical design.
•The idea is to have a realistic proporsal from the
point of view of manufacturing, cost and that meets
the scientific requirements. All the work has to be
documented to create and archive and define
subsystems and interfaces.
•The scope is planned in a series of documented
tasks (next slide).
CONCEPTUAL DESIGN
TASK
PROGRESS
Original Design Documentation. Performances and
improvements
Done.
Doc: NahualBaselineOpticalDesing
Scientific Requirements and subsystems
Done.
Doc:NahualRequirements
To understand Nahual Requirements
Done (Eike)
Doc: Nahual Science and Basic Understanding
ADC need and trade off type.
Done
Doc: NahualCorrectorTradeOff
ADC design
Done
Doc: NahualCorrectorOpticalDesign
Cross dispersion update and trade off
Done
Doc: NahualCrossDispersionTradeOff
Nahual Image Slicer trade off
In progress
Nahual Error budget
In progress
Nahual Conceptual Optical Design
The summary and proposed design
In progress
Contact with main manufacturers (cost, schedule)
Cross dispersion unit
Done
Echelles
Done
Reflective optics: OAPs and Camera
Pending
OPTICAL MANAGEMENT: PRELIMINARY DESIGN
PHASE
•Schedule to be confirmed:
September 2006-September 2007
•Resources: 540h for optical design
•SCOPE for the preliminary design.
•Every aspect of the design will be modeled or
tested to guarantee that the solution will be ready
for final manufacturing drawings.
•Manufacture contacts with more than one supplier
should be done.
OPTICAL MANAGEMENT: PRELIMINARY DESIGN
PHASE
TASK
Thermal analysis: Main optics, ADC , cross dispersion unit.
Two files, for manufacturing, and for operation. Optical optimization.
Ghost analysis. ADC, Cross dispersor and main optics.
Stray light analysis. Baffling and Emissivity issues.
Nahual Error budget. Image quality update.
Nahual Error budget. Thermal/image stability.
Associated systems. A&G IR imaging unit
Associated systems. Gas cell optical effects.
Alignment Integration and Verification.
Preliminary Procedure and tools.
Coating performances. Manufacture and tests.
Preliminary Optical Design. Interface definition
Contact with manufacturers
Manufacturing issues and updates.
OPTICAL MANAGEMENT:
OPTICS COST
OPTICAL
SYSTEM
METHOD
COST (euros)
Two OAPs
Camera
3 Echelle
Quotation
50000 (63º)/80000 (76º)
Cross Dispersion
Unit
Quotation
75000
ADC
Estimation
10000
A&G IR
Autoguide
Image Slicer
(design pending)
WORK IN PROGRESS
Scope:
•To have a complete conceptual design well documented in
September of 2006 regarding the optical design.
Tasks under progress but not ready for today.
• Image slicer design.
• Image quality error budget (fabrication and alignment tolerances).
• Camera and OPAs manufacturer contact and quotations
IMAGE SLICER I.
Seeing statistics at La Palma
•FWHM at V band it the GTC site.
•50% of the time the seeing is under
0.69” arc seconds.
•80% of the time the seeing is under
0.9” arc seconds.
IMAGE SLICER II.
Seeing at J,H and K bands
Measured
FWHM
R0 (0.5microns)
R0 (1.25 microns)
R0 (1.6 microns)
R0 (2.2 microns)
50% Percentile
0.69”
0.146 mts
0.438 mts
0.589 mts
0.864 mts
80% Percentile
0.9”
0.112 mts
0.336 mts
0.452 mts
0.663 mts
•Top: R0 scaling with lambda
FWHM (50% time)
FWHM (80% time)
Lambda 1.25, J band
0.57”
0.75”
Lambda 1.6,H band
0.55”
0.71”
Lambda 2.2, K band
0.51”
0.67”
•Top: Expected FWHM values at J,H and K bands at
50% and 80% of the time.
IMAGE SLICER III.
•Aperture is limited in the telescope seeing mode by the cross
dispersion.
•Simple devices can be designed with three slices (0.175” arc seconds slits)
•The aperture for the proposed design is 0.6125”x0.525”
• A model of the flux
entering the aperture
is on the way. Early
estimations are >80%
Of the flux, 50% of the
time.
IMAGE SLICER IV.
• A trade off analysis regarding the different options is in course.
• Simple cryogenic devices are preferred. It will be placed in the focal
plane wheel.
• Pupil position and plate scale should be maintained for a straight AO
operation.
• Many options are initially available. Those identified that will be
analyzed are:
-Lenslet array with fiber link and pseudo slit.
-Lenslet array
-Reflective. Richardson
-Reflective. Micromirrors
-Refractive. Waveguide. Suto & Takami
-Refractive. Other waveguide modifications
-Refractive. Bowen – Walraven (standard, confocal and
modifications)
-Refractive. Plate Tilting
•
A real test of the final design has to be done in cold if the
assembly has not been previously reported.
ERROR BUDGET I.
• Preliminary analysis has been done considering a 10% mean
degradation over the nominal design. This analysis has to be updated.
• Optical manufacture and alignment tolerances indicate the need of
compensators. The sensitivity analysis pointed the camera as the
mayor offender of the system.
• The considered compensators are
 Detector: piston and tilts.
 Camera: M3 decenter and tilt.
• These compensators are used during the alignment of the instrument,
and will work regarding symmetrical aberrations (spherical and focus),
and non symmetrical ones (astigmatism and coma).
• To validate the procedure contact with companies are needed regarding
the manufacturing tolerances.
A 50 Monte Carlo run with the considered compensators being evaluated
in diffraction ensquared energy. This evaluation was done for the
camera alone to consider a complete manufacturer assembly.
Other Possible Cameras
Camara pru1
SILICA, dia 95mm