1. ZTF Optics Design 2013-02-01 ZTF Technical Meeting 1

2. Optics Outline Overview of Requirements Trade Studies Conceptual Design Future Work 2013-02-01ZTF Technical Meeting 2

3. Requirements Overview Use the Oschin Schmidt telescope primary and corrector Illuminate 12 CCD231-C6 e2v detectors (6k x 6k, 15 µm pixels (~ 1 arcsecond)) –16 detectors had large vignetting and worse imaging (see next slide) R band average FWHM < 1.1 arcseconds (final, including alignment and manufacturing) –Allow 1.0 arcseconds for the optical design G band average FWHM < 1.2 arcseconds (final, including alignment and manufacturing) –Allow 1.1 arcseconds for the optical design Use materials that transmit in the U and I band –May add these filters later 2013-02-01ZTF Technical Meeting 3

4. Requirements Overview (continued) 2013-02-01ZTF Technical Meeting 4 Detector Pattern (with vignetting) No Vignetting 10%Vignetting 20%Vignetting 30%Vignetting

5. Initial Trade Study Inputs Distance from flattener to CCD is >= 2mm Allow distance from Schmidt corrector to mirror to vary Window diameter/thickness <= 14.4 (same as QUEST camera) –Safe to have atmospheric pressure accross Window is Fused Silica All spherical surfaces –Aspheric surfaces did not change performance much Optimize over 5 wavelengths in the g’, r’ bands as below (allowing a focus change). Optimize over 9 field points Merit function is the 2D FWHM (RMS radius * 2.3548) 2013-02-01ZTF Technical Meeting 5

6. Bandpass Definition 2013-02-01ZTF Technical Meeting 6 u’g’r’i’ Wavelength (nm) Wavelength (nm) Wavelength (nm) Wavelength (nm) 325.0398.0593.0719.5 340.0432.5625.5770.75 355.0467.0658.0822.0 370.0501.5690.5873.25 385.0536.0723.0924.5

7. Initial Trade Study Initially did not include a filter in the trade study and concentrated only on the R band –Filter seemed to always make design worse Quicker to analyze to limit trade space 2013-02-01ZTF Technical Meeting 7

8. Initial Trade Study 2013-02-01ZTF Technical Meeting 8 DesignDescriptionG Band FWHM R Band FWHM Classical Schmidt (just for a limiting case) 0.78” 0.65” Curved Focal Plane Powered window 1.85” 1.48” Flat focal plane Powered window 2.20” 1.86” 4 segment focal plane 4 segment window 1.53” 1.21” No designs with flat detectors and vacuum windows met requirements

9. 12 Segment Focal Plane Schematic 2013-02-01ZTF Technical Meeting 9 Filter Window 12 flatteners 12 detectors

10. 12 Segment Focal Plane Schematic Each detector is flat but tilted with respect to the others (see previous slide) –12 chords on focal plane One vacuum window for all detectors (see previous slide) –After FEA center thickness fixed at ~22mm Each detector has its own field flattener (see previous slide) –Allow field flattener to be decentered and tilted 2013-02-01ZTF Technical Meeting 10

11. 12 Segment Focal Plane Inputs Distance from flattener to detector > 2mm (smaller preferred) Distance from flattener to window from 3 mm to 110 mm (larger preferred) Distance from window to filter from 15 mm to 110 mm (larger preferred) Filter, Window, and flatteners are Fused Silica –Good transmission in UV and IR Only Optimized G and R band simultaneously (allowing focus change) Optimize over 5 wavelengths in the g’, r’ bands Optimize over 9 field points in each detector Merit function is the average 2D FWHM (RMS radius * 2.3548) –Use RMS field map with 50 x 50 points 2013-02-01ZTF Technical Meeting 11

12. 12 Segment Focal Plane Trends Thicker Windows degrade optical performance –22mm center window thickness gives factor of safety of 8 (from FEA analysis) Thicker filter degrades optical performance Flat filter degrades optical performance Larger CCD – flattener spacing degrades optical performance 2013-02-01ZTF Technical Meeting 12

13. 12 Segment Trade Study PTF Corrector Distance = 6075.3 mm; Original Corrector Distance = 6122.4 mm (A) = asphere (S) = sphere 2013-02-01ZTF Technical Meeting 13 CaseFilterWindowFlattenerR Band FWHMG Band FWHM Corrector Distance IMeniscus (5mm)Meniscus(A)Off axis9.1µm (0.60”)13.2µm (0.88”)6263.6 mm IIMeniscus (5mm)Plano-Concave(S)Off axis9.1µm (0.61”)14.1µm (0.94”)6214.6 mm IIIMeniscus (5mm)Meniscus(A)On axis9.0µm (0.60”)14.1µm (0.94”)6263.9 mm IVMeniscus (5mm)Plano-Concave(S)On axis9.1µm (0.61”)14.0µm (0.93”)6215.0 mm VMeniscus (5mm)Meniscus(A)Identical9.0µm (0.60”)13.7µm (0.92”)6252.5 mm VIMeniscus (5mm)Plano-Concave(S)Identical9.4µm (0.63”)13.9µm (0.92”)6212.6 mm VIIPlano-Convex (5mm)Concave-Plano(S)Off axis9.4µm (0.63”)14.8µm (0.98”)6013.8 mm VIIIPlano-Convex (5mm)Concave-Plano(S)On axis9.4µm (0.63”)16.8µm (1.12”)6013.9 mm IXPlano-Convex (5mm)Concave-Plano(S)Identical9.5µm (0.63”)16.8µm (1.12”)6014.5 mm XMeniscus (10mm)Meniscus(A)Off axis9.7µm (0.65”)14.5µm (0.97”)6319.2 mm XIMeniscus (10mm)Meniscus(S)Off axis9.8µm (0.65”)15.5µm (1.04”)6250.9 mm XIIMeniscus (10mm)Meniscus(S)On axis9.8µm (0.65”)15.5µm (1.03”)6251.1 mm XIIIMeniscus (10mm)Meniscus(S)Identical10.1µm (0.67”)15.5µm (1.04”)6250.3 mm XIVPlano-Convex (10mm)Biconcave(S)Identical9.7µm (0.65”)16.8µm (1.12”)6108.7 mm XVPlano-Convex (5mm)Biconcave(S)Identical9.1µm (0.60”)14.9µm (1.00”)6107.1 mm XVIPlano-Plano(10mm)Meniscus(A)Identical20.5µm (1.37”)27.7µm (1.85”)6155.5 mm XVIIPlano-Plano(10mm)Meniscus(A)Off axis20.5µm (1.37”)28.0µm (1.86”)6160.9 mm XVIIIPlano-Plano(5mm)Meniscus(A)Off axis18.0µm (1.20”)24.6µm (1.64”)6154.6 mm

14. Case XV Imaging Results (1 Quadrant) R Band average FWHM = 0.60 arcseconds; maximum FWHM = 0.88 arcseconds G Band average FWHM = 1.00 arcseconds; maximum FWHM = 1.26 arcseconds 2013-02-01ZTF Technical Meeting 14 R BandG Band FWHM (arcseconds)

15. Future Work Finish I and U band results Complete optical tolerance analysis –Budget/split tolerances into telescope and cryostat sections E.g. filter location (part is telescope filter mechanism/ part is cryostat manufacture) Complete vignetting/obscuration analysis Complete ghosting/scattered light analysis Complete manufacturability/cost studies 2013-02-01ZTF Technical Meeting 15

16. BACKUP SLIDES 2013-02-01ZTF Technical Meeting 16

17. Detector Field Flattener Detector Gap If t is the thickness of the flattener, d is the distance from detector to the flattener, c is the chamfer of the flattener, g is the gap between the flatteners, f is the f/# of the beam, n is the index of refraction of the glass, and s is the spacing between the detectors, then For g = 2mm, c = 1mm, t = 5mm, d=2mm, f=2.5, n = 1.5 then s = 8.2 mm –I assumed 8.4 mm in the analysis 2013-02-01ZTF Technical Meeting 17

18. Detector Layout Two Detectors layouts have been considered –Minimize the gap in each direction (asymmetrical, need 3 detectors in Zemax) –Place detectors centers on a square grid (symmetrical, need 2 detectors in Zemax) 2013-02-01ZTF Technical Meeting 18 Only the minimize gap has been studied at the moment The square grid version will be a slight modification to the optics DetectorX (mm)Y (mm)xfield (°)yfield (°) 14.2 0.079 150.44.20.9450.079 196.64.21.8100.079 14.250.280.0790.942 150.450.280.9450.942 196.650.281.8100.942 14.296.360.0791.806 150.496.360.9451.806 196.696.361.8101.806 21054.21.9670.079 2151.24.22.8320.079 2197.44.23.6950.079 210550.281.9670.942 2151.250.282.8320.942 2197.450.283.6950.942 210596.361.9671.806 2151.296.362.8321.806 2197.496.363.6951.806 34.2104.760.0791.963 350.4104.760.9451.963 396.6104.761.8101.963 34.2150.840.0792.825 350.4150.840.9452.825 396.6150.841.8102.825 34.2196.920.0793.686 350.4196.920.9453.686 396.6196.921.8103.686 Field locations for minimum gap DetectorX (mm)Y (mm)xfield (°)yfield (°) 14.32 0.081 150.44.320.9450.081 196.484.321.8080.081 14.3250.40.0810.945 150.4 0.945 196.4850.41.8080.945 14.3296.480.0811.808 150.496.480.9451.808 196.48 1.808 2105.124.321.9700.081 2151.24.322.8320.081 2197.284.323.6930.081 2105.1250.41.9700.945 2151.250.42.8320.945 2197.2850.43.6930.945 2105.1296.481.9701.808 2151.296.482.8321.808 2197.2896.483.6931.808 Field locations for square grid

19. Minimize the gap (Zemax settings) RMS field map settings –Ray density = 6 –Data = Spot Radius –Wavelength = All –Method = Gauss Quad –Center field = 5 –Refer To = Centroid –X field size = 0.8655 –Y field size = 0.8655 –X field sampling = 50 –Y field sampling = 50 –Surface = Image Use the text->Window->Copy clipboard to place the data into excel for analysis 2013-02-01ZTF Technical Meeting 19

20. Case XV Optical Prescription (Detector 1) 2013-02-01ZTF Technical Meeting 20 #TypeSurface ROC = (1/c) (mm) Thickness (mm) Glass Diameter (mm) A2A2 A4A4 A6A6 A8A8 1STANDARDCORRECTOR117054.911.481LLF61244.75 2EVENASPHCORRECTOR64570.28517.221BK71245.400-5.68E-1200 3EVENASPHCORRECTOR173900.952850.000 1246.3202.25E-128.01E-200 4STANDARD Infinity3257.102 1501.99 5STANDARDM1-6123.94-2750.000MIRROR1803.40 6STANDARDR band FocusInfinity-39.996 427.63 7STANDARDG band FocusInfinity-40.077 0.00 8STANDARDfilter-2949.311-19.472SILICA403.85 9STANDARD Infinity-110.000 398.98 10EVENASPHwindow4808.0832-22.278SILICA337.210000 11EVENASPH -2123.604-110.000 325.740000 12STANDARDDet 1 focusInfinity-0.569 277.72 Decenter XDecenter YTilt XTilt Y 13COORDBRKFlat1 tiltInfinity0.000 0.0050.674750.5515-1.20431.2203 14STANDARDDet1 flat-731.0547-5.062SILICA132.45 15STANDARD Infinity-2.000 131.67 Decenter XDecenter YTilt XTilt Y 16COORDBRKDet1 TiltInfinity0.000 0.0000-0.05080.0376 27STANDARDFILMInfinity0.000 130.60

21. Case XV Optical Prescription (Detector 2) 2013-02-01ZTF Technical Meeting 21 #TypeSurface ROC = (1/c) (mm) Thickness (mm) Glass Diameter (mm) A2A2 A4A4 A6A6 A8A8 1STANDARDCORRECTOR117054.911.481LLF61244.75 2EVENASPHCORRECTOR64570.28517.221BK71245.400-5.68E-1200 3EVENASPHCORRECTOR173900.952850.000 1246.3202.25E-128.01E-200 4STANDARD Infinity3257.102 1501.99 5STANDARDM1-6123.94-2750.000MIRROR1803.40 6STANDARDR band FocusInfinity-39.996 427.63 7STANDARDG band FocusInfinity-40.077 0.00 8STANDARDfilter-2949.311-19.472SILICA403.85 9STANDARD Infinity-110.000 398.98 10EVENASPHwindow4808.0832-22.278SILICA337.210000 11EVENASPH -2123.604-110.000 325.740000 17STANDARDDet2 focusInfinity-5.000 447.66 Decenter XDecenter YTilt XTilt Y 18COORDBRKFlat2 tiltInfinity0.000 0.00151.532950.3696-0.27091.0101 19STANDARDDet2 flat-731.0547-5.062SILICA133.69 20STANDARD Infinity-2.000 132.98 Decenter XDecenter YTilt XTilt Y 21COORDBRKDet2 tiltInfinity0.000 0.0000-0.98432.7650 27STANDARDFILMInfinity0.000 130.60

22. Case XV Optical Prescription (Detector 3) 2013-02-01ZTF Technical Meeting 22 #TypeSurface ROC = (1/c) (mm) Thickness (mm) Glass Diameter (mm) A2A2 A4A4 A6A6 A8A8 1STANDARDCORRECTOR117054.911.481LLF61244.75 2EVENASPHCORRECTOR64570.28517.221BK71245.400-5.68E-1200 3EVENASPHCORRECTOR173900.952850.000 1246.3202.25E-128.01E-200 4STANDARD Infinity3257.102 1501.99 5STANDARDM1-6123.94-2750.000MIRROR1803.40 6STANDARDR band FocusInfinity-39.996 427.63 7STANDARDG band FocusInfinity-40.077 0.00 8STANDARDfilter-2949.311-19.472SILICA403.85 9STANDARD Infinity-110.000 398.98 10EVENASPHwindow4808.0832-22.278SILICA337.210000 11EVENASPH -2123.604-110.000 325.740000 22STANDARDDet3 focusInfinity-4.977 446.97 Decenter XDecenter YTilt XTilt Y 23COORDBRKFlat3 tiltInfinity0.000 0.0050.5132151.1392-0.95940.2161 24STANDARDDet3 flat-731.0547-5.062SILICA133.69 25STANDARD Infinity-2.000 132.98 Decenter XDecenter YTilt XTilt Y 26COORDBRKDet3 tiltInfinity0.000 0.0000-2.80591.0408 27STANDARDFILMInfinity0.000 130.60