Some performance results from NIRCam's coronagraphic prototype masks

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) is one of the four science instruments installed into the Integrated Science Instrument Module (ISIM) on JWST intended to conduct scientific observations over a five year mission lifetime. NIRCam's requirements include operation at 37 kelvins (K) to produce high resolution images in two wave bands encompassing the range from 0.6 microns to 5 microns. In addition NIRCam is used as a metrology instrument during the JWST observatory commissioning on orbit, during the initial and subsequent precision alignments of the observatory's multiple-segment 6.3 meter primary mirror. This paper describes some preliminary performance results of prototype coronagraph masks.