Aspects of error budgeting for coronagraphic differential imaging:Effects of dust and cosmetic errors

摘要

The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) planet finder instrument for ESO's VLTtelescope, scheduled for first light in 2011, aims to detect giant extra-solar planets in the vicinity of bright stars by the aidof an extreme-AO turbulence compensation system and coronagraphic diffraction suppression. Objects found will becharacterized through spectroscopic and polarimetric observations. I consider here the effects of micro-obstructions ofthe beam due to dust and cosmetic defects on the SPHERE image quality.