Demetrio Magrin INAF – Astronomical Observatory of Padova demetrio.magrin@oapd.inaf.it

1. Demetrio Magrin INAF – Astronomical Observatory of Padova demetrio.magrin@oapd.inaf.it Optical Design Catania, 11/06/2014

2. 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

3. Design parameters

4. BK7 (G18) BK7 S-FPL51 N-KZFS11 KZFSN5 S-FPL53 CaF2 196.2 mm 368 mm Nominal DesignDefinition phase (18/03/2011)

5. Nominal DesignDefinition phase (18/03/2011)

6. Aspheric surface S-FPL51 Maximum deviation from BFS  1.050 mm See R.Ragazzoni presentation

7. Enclosed Energy G0V + detector QE 2x2 pixels

8. Enclosed Energy (through focus) -40 micron +40 micron

9. Spot diagrams and FoV 13.6 deg, 13.6 deg 4x4 pixels 14.3 deg, 14.3 deg

10. About vignetting Natural vignetting 9.0% at the edge of the full FoV 7.5% at the edge of the ‘in spec’ FoV

11. About vignetting Mechanical vignetting 6.4% at the edge of the full FoV 4.2% at the edge of the ‘in spec’ FoV

12. About vignetting Natural + Mechanical vignetting 15.4% at the edge of the full FoV 11.7% at the edge of the ‘in spec’ FoV

13. Polychromatic PSFs PLATOSim

14. Sensitivity Analysis Optical elements defocus  30-50 micron Merit Function: 80%EE< 2×2 pixel2 over the corrected FoV

15. 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.

16. BreadBoard/Prototype Design 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. (J.Farinato / V.Viotto / M.Bergomi presentations)

17. My last ‘New Baseline’… 21/05/2011 • A physical stop in front of L3 (at about 2.84 mm edge to edge). • New weights for the wavelengths used in the Zemax merit function provided by P. Levacher - P. Bernardi. • Change the glass of L5 from KZFSN5 to N-KZFS5 (almost no optical impact and facilitate the procurement). • Change the thicknesses of L5 and L6 from 5mm to 7mm (all the industries suggested to increase these numbers). • Change on all lenses apertures from 1mm to 2mm with respect to the clear aperture. It should help to minimize the mechanical vignetting.

18. 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.