2. SKY BACKGROUND CALIBRATION and CORRECTION José Eduardo Costa

3. Correction by Sky Background ● Standard procedure ● Correction: STAR – SKY

4. CoRoT Sky Background Windows ● SISMO (1s): 5 windows / CCD 50x50 ● EXO (32s): 10 windows / CCD 10x10 ● EXO (512s): 40 windows / CCD 10x10

5. Sky Background ● Straylight from the Earth ● SAA ● Moonlight ● Other sources of light ● Diffusion and reflection SKY BACKGROUND = ADJACENT SKY + PARASITE LIGHT PARASITE LIGHT:

6. Straylight From Earth ● h = 896 km ● P = 1h 42.9min ● f = 162 uHz

7. Straylight and Orbital Position

8. South Atlantic Anomaly (SAA)

9. Effects on SISMO and EXO SISMO EXO

10. Corrections of the Sky Background ● Correction On Board Outline points (cosmic rays) ● Correction On Ground Outline points, SAA and Discontinuity Sky Background Gradient

11. Correction On Board

12. Correction of Outline Points and Discontinuity

13. Asymmetrical Optical System

14. Non-Homogeneous Sky Background

15. Residual Sky Light Curve

16. SBC Program

17. Modelization of the Sky Background Gradient

18. Sky Background Characterization Sky Background Homogeneous Non-homogeneous Regular Irregular f(x,y) = cte f(x,y; t) Local Triang.

19. Irregular Sky Background Local Triangularization

20. SBC – Sky Background Gradient

21. Thank you

22. Zodiacal Light (scattering of the solar light by thin particles of dust)