Table 1
ELT f/5 Design Parameters Optimized Across a
6 arc min FOVa
Mi
| Curvature Radius (mm)
| Thickness from Mi to Mi + 1
| Optical Clear Aperture (mm)
| Hole (mm)
| Conic
| Figure Deviation (Df) from BFS
|
---|
M1 | -71324.73 | -37900.000 | 25000 | 5200 | 0.000 | Spherical |
M2 | +10171.61 | +2788.788 | 2060 | 600 | 18.470 | Prolate ellipsoid, Df = 0.73 mm |
M3 | -5025.15 | -8911.525 | 2690 | 95 | -1.413 | Hyperboloid, Df = 1.12 mm |
M4 | +6311.22 | +5690.573 | 4340 | 280 | -0.291 | Oblate ellipsoid, Df = 0.86 mm |
M5 | +13372.57 | -5797.960 | 1180 | 240 | 0.000 | Aspherical, Df = 1.50 mm |
FP | -1235.43 | | 109.1 | — | 0.000 | Spherical |
M5 |
A = 4.25183 × 10
-11
|
B = 6.12178 × 10
-18
|
C = 1.15078 × 10
-23
|
|
D = 1.42958 × 10
-29
|
E = 2.18073 × 10
-36
|
F = -7.81065 × 10
-42
|
FP is the focal plane, and the plate scale is
S =
1.65 arc sec/mm.
A,
B,
C,
D,
E, and
F
are the fourth-, sixth-, eighth-, tenth-, twelfth-, and
fourteenth-order deformation coefficients, respectively, for aspherical
surface M5.
Table 2
ELT f/5 Compact Design Parameters Optimized
Across a 3 arc min FOVa
Mi
| Curvature Radius (mm)
| Thickness from Mi to Mi + 1
| Optical Clear Aperture (mm)
| Hole (mm)
| Conic
| Figure Deviation (Df) from BFS
|
---|
M1 | -71324.73 | -37900.000 | 25000 | 5200 | 0.000 | Spherical |
M2 | +9426.44 | +2751.595 | 2060 | 600 | 5.882 | Prolate ellipsoid, Df = 0.27 mm |
M3 | -4758.10 | -6657.583 | 2690 | 95 | -1.980 | Hyperboloid, Df = 1.78 mm |
M4 | +3925.87 | +3397.270 | 2680 | 260 | -0.178 | Oblate ellipsoid, Df = 0.32 mm |
M5 | +8361.70 | -4171.702 | 840 | 120 | 0.000 | Aspherical, Df = 0.88 mm |
FP | -1147.50 | — | 54.55 | — | 0.000 | Spherical |
M5 |
A = 9.67111 × 10
-11
|
B = 3.83967 × 10
-17
|
C = 8.53434 × 10
-23
|
|
D = 2.02072 × 10
-28
|
E = -8.78626 × 10
-34
|
F = 1.17403 × 10
-39
|
FP is the focal plane and the plate scale is
S =
1.65 arc sec/mm.
A,
B,
C,
D,
E, and
F
are the fourth-, sixth-, eighth-, tenth-, twelfth-, and
fourteenth-order deformation coefficients, respectively, for aspherical
surface M5.
Table 3
ELT f/5 Two-Axis Two-Mirror Design
Parameters Optimized Across a 3 arc min
FOVa
Mi
| Curvature Radius (mm)
| Thickness From Mi to Mi + 1
| Optical Clear Aperture (mm)
| Conic
| Figure Deviation (Df) from BFS
|
---|
M1 | -71324.73 | -35100.000 | 25000 | 0.000 | Spherical |
F1 | Flat | +803.517 | Prime focus | — | Flat |
M2 | -7961.34 | -4233.515 | 620 | -36.84 | Aspherical, Df = 0.025 mm |
M3 | +6888.43 | +14784.875 | 2960 | -1.413 | Aspherical, Df = 2.33 mm |
FP | +4791.78 | — | 109.09 | 0.000 | Spherical |
M2 |
A = 1.73400 × 10
-11
|
B = -2.14090 × 10
-16
|
C = 1.2962 × 10
-20
| |
D = -3.46076 × 10
-24
|
M3 |
A = -1.32963 × 10
-12
|
B = -3.94137 × 10
-20
|
C = 8.99992 × 10
-28
| |
D = T-2.37205 × 10
-34
|
FP is the focal plane and the plate scale is
S =
1.65 arc sec/mm.
A,
B,
C, and
D are
the fourth-, sixth-, eighth-, and tenth-order deformation coefficients,
respectively, for the M2 and M3 aspherical surfaces.
Table 4
ELT f/5 Single-Axis Three-Mirror Design
Parameters Optimized across a 6 arc min
FOVa
Mi
| Curvature Radius (mm)
| Thickness from Mi to Mi + 1
| Optical Clear Aperture (mm)
| Conic
| Figure Deviation (Df) from BFS
|
---|
M1 | -71000.00 | -37801.612 | 25000 | 0.000 | Spherical |
M2 | +6909.69 | +2880.279 | 2200 | -1.802 | Aspherical, Df = 0.105 mm |
M3 | -5408.37 | -2956.237 | 2400 | -1.990 | Aspherical, Df = 2.83 mm |
M4 | -2318.54 | +1201.699 | 560 | 3.716 | Prolate ellipsoid, D = 0.060 mm |
F1 | Flat | -1202.006 | 560 (350 OBS) | — | Flat |
FP | +5107.41 | — | 218.18 | 0.000 | Spherical |
M2 |
A = 9.43074 × 10
-13
|
B = 1.67840 × 10
-20
| |
C = 1.674180 × 10
-27
|
M3 |
A = 6.91822 × 10
-12
|
B = 2.78349 × 10
-19
| |
C =-5.23827 × 10
-27
|
FP is the focal plane and the plate scale is
S =
1.65 arc sec/mm.
A,
B, and
C are the
fourth-, sixth-, and eighth-order deformation coefficients,
respectively, for the M2 and M3 aspherical surfaces. OBS is the
obscuration diameter.
Table 5
Possible Corrector Designs for f/5
ELTa
Design
| FOV (arc min)
|
D
80 (arc sec)
| Maximum Area Obscuration (%)
| Corrector Cylindrical Box (m × m)
| Stronger Df for Aspherical Mirror (mm)
|
---|
1 × 4 | 6.0 | 0.09 | 8.5 | 4.4 × 9.0 | 1.18 M with Df = 1.50 |
Short | 3.0 | 0.06 | 7.0 | 2.8 × 6.7 | 0.84 M with Df = 0.88 |
2 × 2 | 3.0 | 0.09 | 8.0 | 3.0 × 4.5 | 2.96 M with Df = 2.33 |
1 × 3 | 6.0 | 0.03 | 9.0 | 2.5 × 3.0 | 2.40 M with Df = 2.83 |
D80 is the circle diameter with 80% encircled energy,
Df is the figure deviation from the BFS. 1 × 4 indicates
single-axis four-mirror corrector.