SKY BACKGROUND CALIBRATION and CORRECTION José Eduardo Costa

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

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

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

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

Straylight and Orbital Position

South Atlantic Anomaly (SAA)

Effects on SISMO and EXO SISMO EXO

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

Correction On Board

Correction of Outline Points and Discontinuity

Asymmetrical Optical System

Non-Homogeneous Sky Background

Residual Sky Light Curve

SBC Program

Modelization of the Sky Background Gradient

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

Irregular Sky Background Local Triangularization

SBC – Sky Background Gradient

Thank you

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