Imaging

NIRISS was designed with imaging capabilities in mind. It harbours a sub-set of the NIRCam filter set. Imaging is currently limited to field imaging through the blue filters (<2.5 microns) in the context of WFSS use, to have reference direct images of a spectroscopically studied field. However, NIRISS imaging could in principle be carried as parallel observing, in conjunction with another JWST instrument. For cycle 1, NIRISS Imaging will not be offered for parallel observing.

The plate scale is 0.065 arc seconds per pixel for a field of view (2048×2048 pixels) of 2.2 x 2.2 arc minutes. The detector is read out using four amplifiers so the fame readout time is 10.7 seconds so the duty cycle for a CDS (reset+read+read) is 32.1 seconds.

The detailed filter transmission curves can be found here . Below is the throughput (telescope+instrument+filter+detector) for all 12 filters.