Transcript ASTEROSEISMOLOGY and SEARCH for EXOPLANETS ACHIEVABLE CHARACTERIZATIONS ON THE INSTRUMENT Optical performance characterization Point Spread Function (PSF) : Telescope + Dioptric Objectif Sensitivity of.

ASTEROSEISMOLOGY and SEARCH for EXOPLANETS
ACHIEVABLE CHARACTERIZATIONS ON THE INSTRUMENT
Optical performance characterization
Point Spread Function (PSF) : Telescope + Dioptric Objectif
Sensitivity of the PSF with temperature (in 12 points of the field)
Baffle performance characterization
Modelisation of the straylight attenuation achieved with technical manufacturing hypothesis
(coating diffusion, diffraction and quality of the chicanes against grazing incidence reflections, contamination)
Caracterisation of this hypothesis after manufacture
No possible measurement of the attenuation factor (10 -13)
Vienna - September 18th 2001
ASTEROSEISMOLOGY and SEARCH for EXOPLANETS
ACHIEVABLE CHARACTERISATIONS ON THE INSTRUMENT
Camera performance characterization
To adjust interface between Objective and Focal Plane and to obtain the good PSF : Two optical system simulators
- star simulator with the best representativity of the spectral response
- colimator to simulate performances of telescope
Caracterisation of the PSF sensitivity with temperature
CCD Calibration : dark signal, uniformity, spectral quantum efficiency ...
Electronic performance characterization
Noise value (rms and frequency determinist)
Offset and gain
Electronic performances (stability) are not compliant with the need of the mission : Corrections are necessary
 Gain and offset sensitivity with temperature
Vienna - September 18th 2001
ASTEROSEISMOLOGY and SEARCH for EXOPLANETS
Why a need of modelisation ?
•Technical difficulties to measure performances on the integrated instrument
•Attenuation of light for the baffle
•Quality and stability with the temperature of the PSF when the instrument is complitely integrated
(in vacuum, at -40°C and class 100)
•Cost and delay for the instrument tests
•The modelisation allows :
•To assemble the performances of different sub-systems :
•Telescope + Dioptric Objectif
•Camera
•Electronic
•Scientific processing (with calibration data)
•To model the variation of performances with :
the variation of temperature along the orbit
the fluctuation of the pointing system
•To validate the expected gain with the ground correction
Vienna - September 18th 2001