NICI: combining coronagraphy, ADI, and SDI
  The Near-Infrared Coronagraphic Imager (NICI) is a high-contrast AO imager at the Gemini South telescope. The camera includes a coronagraphic mask and dual channel imaging for Spectral Differential Imaging (SDI). The instrument can also be used in a fixed Cassegrain Rotator mode for Angular Differential Imaging (ADI). While coronagraphy, SDI, and ADI have been applied before in direct imaging searches for exoplanets. NICI represents the first time that these 3 techniques can be combined. We present preliminary NICI commissioning data using these techniques and show that combining SDI and ADI results in significant gains. 
Etienne Artigau, Beth A. Biller, Zahed Wahhaj, Markus Hartung, Thomas   L. Hayward, Laird M. Close, Mark R. Chun, Michael C....