Calibration
Astrometry and Photometry
A grid of artificial speckles can be created with a precisely calibrated amplitude that can be used to calibrate the photometry and astrometry to the companion. The speckles are created by the deformable mirror and can be placed at any location/orientation (within the control region of the DM) in the focal plane. Their brightness can also be controlled. This enables astrometry behind the coronagraph and offers a unique avenue to contrast calibration.Calibration source
The internal calibration source consists of a Fianium super continuum source and 2 laser diodes centered at 650 and 1550 nm. The light from the source is delivered via an endlessely single-mode fiber to the bench ensuring a diffraction-limited calibration PSF from the visible to K-band. The brightness and spectral bands of the injected light can be easily controlled. In addition there is a turbulence simulator that can be used for realistic simulations of on-sky performance in the laboratory.
(Left) Internal calibration source unit (a.k.a rainbow maker). (Middle) Super continuum laser source attached to source box. (Right) Internals of
calibration source box. There is a shutter to turn the light on/off, and three wheels to control the ND in the vis/IR and spectral content.
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