SKY BACKGROUND CALIBRATION and CORRECTION

SKY BACKGROUNDCALIBRATION and CORRECTION

José Eduardo Costa

Correction by Sky Background

● Standard procedure

● Correction: STAR – SKY

CoRoT Sky Background Windows

● SISMO (1s):5 windows / CCD50x50

● EXO (32s):10 windows / CCD10x10

● EXO (512s):40 windows / CCD10x10

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 BoardOutline points (cosmic rays)

● Correction On GroundOutline points, SAA and

DiscontinuitySky 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 BackgroundLocal Triangularization

SBC – Sky Background Gradient

Thank you

Zodiacal Light

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