Spectral range500 – 1000 nm Entrance Pupil Diameter120 mm Working F/#2.06 @ 700 nm Field of View1151.5 degree 2 Image quality 90% Enclosed energy < 2×2 pixel 2 over 1108.3 degree 2 Maximum Field Distortion5.043% Plate scale15 arcsec/pixel Pixel size18 micron CCD format4510×4510 (×4) pixel 2 FPA size164.36 mm (2 mm CCDs gap) Optical elements weight 5 Kg (<6 Kg) Working Temperature-80°C Working Pressure0 atm Design parameters
Nominal Design Definition phase (18/03/2011) BK7 (G18) S-FPL51 N-KZFS11 CaF2 S-FPL53 KZFSN5 BK7 368 mm 196.2 mm
ElementDecentering (+/- in micron) Tilt (+/- in degrees) L1800.07 L21000.05 L3300.03 L4600.03 L5600.05 L61000.10 Sensitivity Analysis Optical elements defocus 30-50 micron Merit Function: 80%EE< 2×2 pixel 2 over the corrected FoV
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.
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)
1)A physical stop in front of L3 (at about 2.84 mm edge to edge). 2)New weights for the wavelengths used in the Zemax merit function provided by P. Levacher - P. Bernardi. 3)Change the glass of L5 from KZFSN5 to N- KZFS5 (almost no optical impact and facilitate the procurement). 4)Change the thicknesses of L5 and L6 from 5mm to 7mm (all the industries suggested to increase these numbers). 5)Change on all lenses apertures from 1mm to 2mm with respect to the clear aperture. It should help to minimize the mechanical vignetting. My last ‘New Baseline’… 21/05/2011
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. Open Issues