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NICI Schematic

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The NICI components described in the following sections are arranged as shown in this block diagram. For additional drawings see the NICI Optical Diagrams page.

NICI Block Diagram

Fiber Optic Calibration Source

The Calibration Source is a 4-position slide carrying single-mode fibersfor AO and science detector characterization and calibration.

AO Relay

The AO relay is an 85-element curvature AO system with an APD (Avalanche PhotoDiode) wavefront sensor.

Pre-Dichroic Optics

After the AO system, the beam reaches the Focal Plane Mask wheel which provides coronagraphicmasks. The beam then enters the science camera cryostat and is collimated by an off-axis paraboloid. All poweredoptics in the NICI science camera are mirrors to minimize ghosting. The collimator forms an image of thepupil on the Spider Mask and Pupil Mask wheels, which stop down the pupil image. The beam is thensplit by the Dichroic/Beamsplitter wheel into the two science channels:Channel 1 (or "Red") which receivesthe transmitted light and Channel 2 (or "Blue") which receives the reflected light.

Post-Dichroic Dual Channels

After the beam-splitter, the light in each channel passes through a Filter wheelbefore proceeding to the camera mirrors and detectors. In addition, Channel 1 has a pupil imagingcapability used primarily to align the science camera's pupil with the telescope.

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