JWST's Near Infrared Imager and Slitless Spectrograph (NIRISS) has observing modes for imaging, low resolution wide-field grism spectroscopy, single object grism spectroscopy, and high spatial resolution imaging using aperture masking interferometry.
The JWST Near Infrared Imager and Slitless Spectrograph (NIRISS) has 4 observing modes with unique capabilities for imaging and spectroscopy.
- Wide field slitless spectroscopy (0.8–2.2μm) over a 2.2' × 2.2' field of view using two identical orthogonal grisms with R = λ/Δλ = 150.
- Single object slitless spectroscopy (0.6–2.8μm) for bright targets in two cross-dispersed orders using the R = λ/Δλ = 700 grism.
- Aperture masking interferometry which offers the highest spatial resolution imaging on the JWST, using a non-redundant mask (NRM), reaching a contrast of 10-4 for separations of 70–400 mas.
- Imaging (0.8–5.0μm) over a 2.2' × 2.2' field of view with pixel scale ≈ 0.065"/pixel.
Table 1. Specific properties of NIRISS observing modes
|0.8–2.2||133 × 133||0.065||150 @ 1.4 μm||...|
|...||0.065||700 @ 1.4 μm||...||Subarrays are standard; |
|Aperture masking |
|5.2 × 5.2||0.065||...||...||Subarray is standard; |
|Imaging||0.8–5.0||133 × 133||0.065||4–10||2 pix @3.4 μm|
Full-frame standard; only used in parallel mode
Published November 16, 2016