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Introduction of SONG telescope design. Guomin Wang, Bozhong Gu, Xiangyan Yuan Zhiyong Zhang, Xiang Jiang, Shihai Yang The Third Workshop of SONG 2010-3-30 Beijing. Outline:. General requirements. Structure design introduction. Conclusions. SONG Optical layout. - PowerPoint PPT Presentation
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Introduction of SONG
telescope design
Guomin Wang, Bozhong Gu, Xiangyan YuanGuomin Wang, Bozhong Gu, Xiangyan YuanZhiyong Zhang, Xiang Jiang, Shihai Yang Zhiyong Zhang, Xiang Jiang, Shihai Yang
The Third Workshop of SONGThe Third Workshop of SONG2010-3-302010-3-30
Beijing Beijing
Outline:
General requirements.
Structure design introduction.
Conclusions.
SONG Optical layout
Design specifications
Primary mirror diameter: 1.0m;
Alt-az mount;
Two Nasmyth foci;
FOV at Nasmyth focus: 15′;
System focal ratio (Nasmyth focus): F/36.7
Design specifications
M3 is used to direct light to two Nasmyth foci;
Distance of M3 above M1: 250mm;
Diameter of M3: 206mm;
M2 is supported using active positioning system;
Diameter of M2: 122mm;
Distance between M1 and M2: 2669.926mm;
Mount is compatible with the Coude system;
Azimuth axis specifications
Azimuth rotation range: ±270°(TBD);
Slew speed: > 20°/sec;
Acceleration/deceleration of rotation: >2°/s2;
Resolution of rotation: < 0.01arcsec;
Elevation axis specifications
Elevation rotation range:
5°to 89.5°in operation (TBD)
0°to 90°in maintenance Slew speed: > 20°/sec; Acceleration/deceleration of rotation:
> 2°/s2; Resolution of rotation: < 0.01arcsec; Blind spot: < 1°;
Pointing and tracking specifications
Pointing accuracy:
≤ 5″over all sky, ZD < 70°,with pointing model;
≤ 0.5″over 1.5 degree;
Tracking accuracy(without AGU):
< 1″ RMS over 30min;
< 0.3″over 90 sec;
First resonance frequency: > 10 Hz;
2. Structure design
4584mm
2460mm
1880mm
Baffle style is TBD
Animate of telescope
Gimbal structure
Pier
Base
Fork
Elevation axis
Azi
mu
th
axis
Azimuth axis structure
800×1080×120mm 345×450×110.5m
m
ERA 880C
Basement FEM calculation
Max. deformation: 0.0764mm ;
Max. stress: 39.9Mpa;
Fork structure
single part, easy to mount and alignment, and to ensure the position accuracy of elevation axis;
welded structure with steel plates; thermal treatment to relieve stress;
Fork FEM calculation
Max. deformation: 0.0123mm ;
Max. stress: 2.36Mpa;
Elevation axis structure
Bearing BearingTape
encoder
Driving motor
OSS (Tube) structure
Serrurier truss; Primary mirror supporting: vertical: 18-point whiffletree; lateral: counterweight lever;
OSS FEM calculation
M1-M2 relative offset calculation
uy ( mm) uz ( mm) rotx (″)
0 4.53E-05 -1.57E-02 0.00
10 -3.07E-02 -1.54E-02 -0.89
20 -6.13E-02 -1.47E-02 -1.67
30 -9.09E-02 -1.36E-02 -2.34
40 -1.18E-01 -1.20E-02 -2.90
50 -1.42E-01 -1.00E-02 -3.33
60 -1.62E-01 -7.78E-03 -3.65
70 -1.77E-01 -5.31E-03 -3.88
80 -1.86E-01 -2.71E-03 -4.01
90 -1.90E-01 -5.36E-05 -4.05
-0. 2
-0. 15
-0. 1
-0. 05
0
0. 05
0 10 20 30 40 50 60 70 80 90
el evati on angl e(degree)
uy(m
m)
-0. 018
-0. 016
-0. 014
-0. 012
-0. 01
-0. 008
-0. 006
-0. 004
-0. 002
00 10 20 30 40 50 60 70 80 90
el el vati on angl e(degree)
uz(m
m)
-4. 50
-4. 00
-3. 50
-3. 00
-2. 50
-2. 00
-1. 50
-1. 00
-0. 50
0. 00
0. 50
0 10 20 30 40 50 60 70 80 90
el evati on angl e(degree)
rotx
(arc
)
M2 supporting structure
4 vanes connecting to top-ring; Active positioning system: δx, δy,
δz, θx, θy; Baffle for stray light;
M3 supporting structure
4 vanes connecting to center section;
Motorized to achieve rotation for two Nasmyth foci;
M3
reducer
motor and encoder
bearing
connecting part to center section
Modal calculation
Mode Frequency (Hz) Mode shape
1 31.36 Truss lateral
2 39.14 Truss fore-and-aft
3 48.26 Vanes torsion
4 50.85 Fork lateral
5 52.62 Fork fore-and-aft
6 61.77 Fork torsion
Control system
Conclusions:
It is just conceptual design. More detail calculation is needed, such as the motor torque, bearing stiffness, etc. and more innovative structure is needed to improve the performance further.
The preliminary structure design and calculation show that the telescope requirements can be met;
Thank you !!!Thank you !!!