Transcript presentazione - INAF - Osservatorio Astrofisico di Catania

Demetrio Magrin
INAF – Astronomical Observatory of Padova
[email protected]
Optical Design
Catania, 11/06/2014
Outlines

Design parameters (Definition phase)

Nominal Baseline (Definition phase)

Nominal Performances (EE, spot diagram, PSFs, vignetting factor)

Sensitivity and thermal analysis

Breadboard – Prototype

New (Last…) Baseline

Open Issues
Design parameters
Spectral range
Entrance Pupil Diameter
Working F/#
Field of View
500 – 1000 nm
120 mm
2.06 @ 700 nm
1151.5 degree2
Image quality
90% Enclosed energy < 2×2 pixel2 over 1108.3
degree2
Maximum Field Distortion
Plate scale
Pixel size
CCD format
FPA size
Optical elements weight
Working Temperature
Working Pressure
5.043%
15 arcsec/pixel
18 micron
4510×4510 (×4) pixel2
164.36 mm (2 mm CCDs gap)
5 Kg (<6 Kg)
-80°C
0 atm
Nominal Design
Definition phase (18/03/2011)
BK7 (G18)
S-FPL51
BK7
N-KZFS11
S-FPL53
196.2 mm
CaF2
Y
X
Z
368 mm
KZFSN5
Nominal Design
Definition phase (18/03/2011)
window
Lens 1
Lens 2
Lens 3
Lens 4
Lens 5
Lens 6
FPA
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
R
(mm)
infinity
infinity
177.857
infinity
795.855
135.943
151.697
-225.536
-742.200
-139.241
-101.194
-144.005
-103.083
infinity
infinity
Thickness
(mm)
6.000
2.000
23.000
27.351
7.000
56.975
23.000
59.886
17.000
16.240
5.000
115.547
5.000
4.000
Glass
K
a4
a6
BK7G18
S-FPL51
Shape
circular
-3.681
3.605E-8
-4.020E-12
circular
NKZFS11
circular
CAF2
circular
S-FPL53
circular
KZFSN5
circular
N-BK7
(G18)
circular
square
Diameter
(mm)
190
190
178
178
142
130
114
116
130
131
129.6
135.4
154
184
Aspheric surface S-FPL51
25
20
15
mm
Surface Sag
BFS Sag
10
5
0
0,0
10,0
20,0
30,0
40,0
50,0
60,0
70,0
80,0
mm
Maximum deviation from BFS
 1.050 mm
1,2
1
mm
0,8
0,6
Deviation
0,4
See R.Ragazzoni presentation
0,2
0
0,0
10,0
20,0
30,0
40,0
mm
50,0
60,0
70,0
80,0
Enclosed Energy
G0V + detector QE
2x2 pixels
Enclosed Energy (through focus)
-40 micron
+40 micron
Spot diagrams and FoV
4x4 pixels
13.6 deg, 13.6 deg
14.3 deg, 14.3 deg
About vignetting
Natural vignetting
9.0% at the edge of
the full FoV
7.5% at the edge of
the ‘in spec’ FoV
About vignetting
Mechanical vignetting
6.4% at the edge of
the full FoV
4.2% at the edge of
the ‘in spec’ FoV
About vignetting
Natural + Mechanical vignetting
15.4% at the edge of
the full FoV
11.7% at the edge of
the ‘in spec’ FoV
Polychromatic PSFs
PLATOSim
Sensitivity Analysis
Element
L1
L2
L3
L4
L5
L6
Decentering
(+/- in micron)
80
100
30
60
60
100
Tilt
(+/- in degrees)
0.07
0.05
0.03
0.03
0.05
0.10
Optical elements defocus  30-50 micron
Merit Function: 80%EE< 2×2 pixel2 over the corrected FoV
Thermal Analysis
• In the case of the of a uniform change of the temperature the optical system
has 2 C of tolerances without the need of refocusing. With a temperature change
of 10 C the nominal performances are still recoverable by applying a defocus
through the three resistors.
• In the case of temperature gradient around the nominal temperature, the
optical system maintain the nominal performance with a T=5 C without the
need of refocusing. While the performances are recoverable by applying a
defocus in the case of a T=10 C.
BreadBoard/Prototype Design
L6
L1*
L2*
L3
L4
L5
Window
L6
Y
X
L1
Z
L2
L3
L4
The baseline design has been modified to
allow the SESO tools adaptation (surfaces
curvatures) and to facilitate and to speed up
the manufacturing and mounting processes
(some thicknesses and apertures have been
increased). For procurement reasons, the
glass of L5, KZFSN5, has been substituted by
N-KZFS5.
L5
(J.Farinato
/
presentations)
Y
X
Z
V.Viotto
/
M.Bergomi
My last ‘New Baseline’… 21/05/2011
1) A physical stop in front of L3 (at about
2.84 mm edge to edge).
2) New weights for the wavelengths used in
the Zemax merit function provided by P.
Levacher - P. Bernardi.
3) Change the glass of L5 from KZFSN5 to NKZFS5 (almost no optical impact and
facilitate the procurement).
4) Change the thicknesses of L5 and L6 from
5mm to 7mm (all the industries suggested
to increase these numbers).
5) Change on all lenses apertures from 1mm
to 2mm with respect to the clear aperture.
It should help to minimize the mechanical
vignetting.
Open Issues



Data mining… (about 3 years to resurrect).
Converge on a well-identified design to use as baseline.
Optimize the design for new/modified requirements.
Plate scale, PSF size, window material and thickness, 2 F-TOUs dedicated design.

Perform a detailed manufacturing/alignment tolerances
and consolidate sensitivity/thermal analysis.
RUAG warnings: the design is tight/ de-spacing tolerances are sub-micron.


Double-check performances in terms of EE/Simulator
Contact SESO and discuss the upgrade from
breadboard to prototype with the related implications.