WIYN MISSION

The WIYN Observatory supports the current and future research and
education needs of its scientists by operating and maintaining the
WIYN facilities at a superb level of performance, and by developing
opportunities to enable frontier astrophysical research.
       
  Topics
   · 

Optics General
  ·  Primary
  ·  Secondary Mirror
  ·  Tertiary Mirror
   · 

Bare RC Telescope
   · 

MOS Corrector
   · 

Modified Cass Port
   · 

ADC Corrector
   · 

Active Optics
   · 

DIQ
   · 

Telescope
   · 

Dome
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 WIYN Facts
Optics General
Optics  
Primary Diameter 3498.85mm (137.75")
Primary Focal Ratio 1.7505
Tertiary Location Above Primary 475.4mm (18.72")
Baffle Diameter 1446.2mm (56.94") 17.1%
Primary Mirror
Primary Mirror  
   
Blank Diameter 3511.55mm (138.25")
Diameter (to bevels) 3498.85m (137.75")
Edge Thickness 463.9mm (18.264")
Center Hole Diamter 965.2mm (38")
Sagitta 124.92mm (4.918")
Cass Hole Sagitta 9.4mm (0.370")
Glass Borosilcate
Mirror Weight 1964Kg (4320lbs)
Cell Weight 5854Kg (12,280lbs)
CG Location 468mm (18.43") from vertex
Surface Quality 0.025 waves rms
0.34 waves P-V
0.09 arcseconds FWHM @ 500nm
Surface Roughness 8 Angstrom average
Secondary Mirror
Secondary  
   
Diameter 1200mm (47.25")
Center Thickness 156mm (6.142")
Glass Zerodur
Weight 119.5Kg (263lbs)
Cell Weight 110Kg
Surface quality 0.024 waves rms
0.26 waves P-V
Surface Roughness 11.6 Angstroms average
   
Secondary Articulation  
Focus Travel 1.5cm
Linear Resolution 0.125 micron steps
Pivot Point Location 310mm (12.23") above secondary
Tilt Resolution 0.014 arcsec angular image displacement
Speed 1600 steps per second
Tertiary Mirror
Tertiary
   
Ellipse Dimensions 1101mm x 776mm
(43.35" x 30.55")
Thickness 101.6mm (4.00")
Weight 60Kg (132 lbs)
Cell Weight 79Kg (173 lbs)
Glass Zerodur
Surface Quality 0.026 waves rms
0.428 waves P-V
0.022 arcseconds FWHM
Surface Roughness Bettern than 20 Angstroms
As Built Optical Prescriptions
Bare RC Telescope (WIYN and Folded Cass ports)
Ports
   
Effective Focal Length 22004.5
Total Track 4202.87
Image Space F/# 6.28906
Exit Pupil Diameter 1361.08
Exit Pupil Position -8559.89
Back Focal Distance 2706.81
Plate Scale (On Axis) 9.372 arcseconds/mm
Distortion 0.002%
0.2 degree off axis
Magnification 3.5915
Field of View 12 arcminute (approximate)
Wavelength Coverage Panchromatic
Lens Units Millimeters
Surface Radius Thickness Glass Diameter Conic
STO -12253.5 -4202.869 MIRROR 3500 -1.0708
2 -5332 4202.869 MIRROR 1136.592 -3.74
3 Infinity -475.4   536.8658 0
4 Infinity 0   797.9691 0
5 Infinity -3182.21 MIRROR 604.2212 0
IMA 0   15.653 0
 
Wide Field Corrector (MOS port)
   
Effective Focal Length 21980.8
Total Track 6902.25
Image Space F/# 6.28024
Exit Pupil Diameter 1177.87
Exit Pupil Position -7399.59
Back Focal Distance 2699.01
Plate Scale (On Axis) 9.384 arcseconds/mm
Plate Scale (63% field R) 9.408 arcseconds/mm
Distortion 0.635%
0.5 degree off axis
Magnification 3.5877
Field of View 1 degree
Wavelength Coverage 0.49 to 1.1 microns
Lens Units Millimeters
Surface Radius Thickness Glass Diameter Conic
STOP -12253.5 MIRROR 3498/85 -1.0708
2 4203.239 MIRROR 1118.326 -3.74
3 Infinity -475.4   693.5089 0
4 Infinity 2267.51   748.2776 0
5 20 SILICA 484.655 0
6 1   482.0019 0
7 20 SILICA 476.3526 0
8 0   466.5941 0
9 Infinity 865.9   472.1198 0
10 Infinity 0   386.6157 0
IMA 0   385.9148 0
 
FEL

Autocad cross section of the two element corrector.
   
The corrector consists of two fused silica lenses with all spherical surfaces in an elastomeric mounting to a PH-17 stainless steel cell.
Lens Diameter 500mm (19.685")
Cell Diameter 543.8mm (21.41")
Wavefront Quality 0.074 waves rms
0.38 waves P-V
This is the full aperture wavefront quality, however the wavefront to any one image is much smaller, hence the wavefront error contribution is negligible.
 
Modified Cass Port
 (An Axi-Symmetric Focus for Polarimetry)
Effective Focal Length 47819.86mm
Image Space F/# 13.665
Exit Pupil Diameter 88.9mm
Exit Pupil Position -1227mm
Back Focal Distance 485.417mm
Plate Scale (On Axis) 4.314 arcseconds/mm
Magnification 2.173 f(13.7)/f(6.3)
Field of View 10 arcminutes (approx. diam.)
Radius of Focal Plane -190.64mm
Wavelength Coverage Panchromatic
Surface Radius Thickness Glass Diameter Conic
-2000 0 MIRROR 359.0 -3.799155(-e2)
-354.85 -517.44 MIRROR 100.0 -1.44617
-190.64 1002.84   130.0 0
   
Reimager




Autocad cross-section of the two element f/6.3 to f/13.665 reimager.
The reimager provides a four-reflection focus at higher magnification with low polarization optics (i.e. no 45 degree fold mirror). The f/13.665 focus is equipped with an instrument rotator and can support an instrument up to 200 lbs. The floor-to-focus clearance is approximately one meter.
 
   
ADC Corrector
(Can be installed or removed on WIYN port only)
1 -2000
2 -354.85
IMA -190.64
Effective Focal Length 22369.4
Total Track 6910.89
Exit Pupil Diameter 562.13
Exit Pupil Position -3593.94
Back Focal Distance 2706.81
Plate Scale (On Axis) 9.221 arcseconds/mm
Plate Scale (63% R) 9.232
Distortion 0.246%
(0.25 degrees off axis)
Magnification 3.6511
Field of View 0.5 degrees
Wavelength Coverage 0.35 to 1.05 microns
Lens Units Millimeters
Surface Radius Thickness Glass Diameter Conic Angle
STO -4203.868 MIRROR 3498.85 -1.0708  
-12253.5 4203.868 MIRROR 1143.869 -3.74  
2 -5332.5 -475.4   561.7073 0  
3 Infinity 2671.42   627.0687 0  
4 Infinity 18 LLF1 259.7828 0  
5 Infinity 28 PSK3 258.2231 0  
6 Infinity 64   256.7133 0 2.608
7 -777.899 15 PSK3 235.3227 0  
8 -603.869 19 LLF1 233.6373 0  
9 Infinity 367   232.4383 0 3.400
10 Infinity 0   195.7279 0  
IMA Infinity          
   
ADC lens is mounted on a slide for remotely controllable deployment or removal from the beam. The two lenses are mounted on rotating stages with 0.1 degree step resolution.
   
Active Optics
Active Optics


Francois Roddier inspects the active optics hardware on the back of the primary mirror cell.
   
Lateral Actuators 24 passive
Axial Actuators 66 passive - active
Active Force Range Push 1110 Nt (250 lb)
Active Force Range Pull to 876 Nt (197 lb)
Correction Modes Astigmatism, trefoil
   
Delivered Image Quality (DIQ)
Images taken with WIYN
Images taken with the WIYN telescope.
   
Best FWHM measured 0.30 arcseconds
Median FWHM (72 samples) 0.65 arcseconds
Typical profile 80% ee 1.89 x FWHM
Typical Profile 90% ee 2.45 x FWHM
   
Telescope
Telescope  
   
Total Moving Weight 33,060 Kg (72,740 lb)
Elevation Axis Weight 16,170 Kb (35,580 lb)
Component Weights Fixed:  
Az Square Frame 7440 lb
Az Bearing 350
Az Brg Pedestal 1938
Sole Plate 1510
Fixed Total 11,238
Azimuth  
Cone 11,160
Fork 21,000
El Pillow Blocks (2) 5000
Nasmyth Instruments (2) 3000
Az Total: 37,160
Elevation  
Cass Instrument 400
Center Section 8950
Motor counterweights (2) 880
Elevation Sectors (2) 1240
Main Truss 2576
Head Frame 1057
Felxion bars (4) 696
Primary Cell 11,039
Primary Mirror 4321
Tertiary Pedestal 450
Cell Fixed Weights 400
Mirror Cover 425
PM Cell Weights 1282
El Total: 35,578
MOI Elevation Axis 6.4 E5 in-lb-sec2
MOI Azimuth Axis 1.16 E6 in-lb-sec2
Swing Radius 5370mm (211.44")
Height to El Axis 2517.8mm (99.125")
   
Dome
Telescope and Enclosure  
   
Polyhedral Shape Truncated Rhombi-cube Octahedron
Length Across Flats 15m (50 ft)
Volume 1007 m3 (1.340 cu yd)
Skin Insulation R12
Skin Surface Area 386 m2 (467 sq yd)
Moving Weight 40 tons
Slit Width 4.2m
Vent Area 55.5m2
Average Surface Density 0.10 tons/m2
   
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WIYN Interior Schematic

Additional Information
For more information contact:
WIYN Observatory
950 N. Cherry Ave.
Tucson, AZ 85719
E-mail: wiyn-contact@noao.edu

 

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