1. 1 Maestro Lens Mounting Lenses 4 and 6 –Mounting method: Potted on OD with elastomer (athermalized) –Lens diameter = 10.63 inches –Lens CTE (  l ) = 3.5x10 -6 /  F –Elastomer CTE (  e ) = 178.0x10 -6 /  F = 0.4992 –Cell, Aluminum (to match L5 CTE) CTE (  c ) = 13.0x10 -6 /  F

2. 2 Athermalization Calculation Assume elastomer layer is constrained –Thermal expansion of elastomer (h = thickness of elastomer layer) =  e *((1+ )/(1- ))*  T*h = 2.994  e  T*h –Thermal expansion of cell (D = diameter of lens) =  c *  T*(D/2+h) –Thermal expansion of lens =  l *(D/2)*  T –The mounting is athermalized if the expansion of the elastomer equals the cell expansion less the lens expansion: –2.994  e  T*h =  c *  T*(D/2+h) -  l *(D/2)*  T This is true if: –h = (  c -  l )*(D/2)/(2.994  e -  c ) = 0.097 inches After adjusting for shape effects (finite width) –h = 0.102” for L4 and 0.102” for L6

3. 3 Finite Element Model of Lens L4 Lens L4 Elastomer Layer

4. 4 Finite Element Model of Lens L6 Lens L6

5. 5 Lens L4 Results, No Axial Locators –1 g Z cases are on elastomer and on elastomer supplemented by axial supports. –1 g Y and Z hydro cases do not include gravitational acceleration

6. 6 Lens L6 Results, No Axial Locators 1 g Z cases are on elastomer and on elastomer supplemented by axial supports. 1 g Y and Z hydro cases do not include gravitational acceleration

7. 7 Lens L4 Results, Three Axial Locators 1 g Y and Z hydro cases do not include gravitational acceleration

8. 8 Lens L6 Results, Three Axial Locators 1 g Y and Z hydro cases do not include gravitational acceleration

9. 9 Lens L4 Results, Six Axial Locators 1 g Y and Z hydro cases do not include gravitational acceleration

10. 10 Lens L6 Results, Six Axial Locators 1 g Y and Z hydro cases do not include gravitational acceleration

11. 11 Residual Deformation if Bonded on Three Points Assume 500*sin(3*  )  -inch deformation when bonded (Actual 1 g trifoil is < 1.75  -inch) Residual trifoil in lens L4 is 2.7  -inch (0.54%) Residual trifoil in lens L6 is 3.05  -inch (0.61%) Conclusion: The lens can be supported on 3 OD points while bonding. When the weight is removed from the 3 support points 99.4% of the trifoil present during bonding will disappear.

12. 12 Thermal Stress and Elastomer Thickness Lens 4

13. 13 Thermal Distortion, 100 deg F Change, L4 Cell Lens and Cell Elastomer (a narrow strip with the same shape factor is required). Lens and Cell

14. 14 Thermal Results, 100 deg F Change, L4 To investigate large thermal distortions an aluminum cell was added to the model and the methodology revised to allow accurate distortion calculation (I.e. normalize CTE’s to the glass value to remove large dimensional changes related only to thermal expansion). Results for various configurations of the elastomer layer: – Case Lens distortion –Full lens height0.81 waves P-V –Half lens height0.092 waves P-V –Half height, half circumf.0.058 waves P-V