NIRCam Observing Modes
JWST Near Infrared Camera (NIRCam) has 5 observing modes: imaging, coronagraphy, grism wide field slitless spectroscopy, time-series imaging, and grism time series.
NIRCam's 5 observing modes for science, from 0.6 to 5.0 µm, have corresponding templates in the Astronomer's Proposal Tool (APT):
- Imaging of two 2.2' × 2.2' fields separated by 44" covering 9.7 arcmin² in total
- Coronagraphic imaging using focal plane occulting masks and pupil plane Lyot stops
- Wide field slitless spectroscopy (2.4–5.0 µm) using R = λ/Δλ ~ 1,600 (at 4 µm) grisms
- Time-series imaging (photometric monitoring)
- Grism time series (spectroscopic monitoring, now including grism spectroscopy in the short wavelength channel for Cycle 4)
Simultaneous observations of the same field of view are available in the short wavelength channel (0.6–2.3 µm) and long wavelength channel (2.4–5.0 µm).
Table 1. Properties of NIRCam observing modes
Observing mode | Wavelength | Field of view§ | Pixel | Notes |
|---|---|---|---|---|
| 0.6–2.3 | 2 × 132" × 132" | 0.031 | FWHM 2 pix at 2.0 µm | |
| 2.4–5.0 | 2 × 129" × 129" | 0.063 | FWHM 2 pix at 4.0 µm | |
1.8–2.2 | 20" × 20" | 0.031 0.063 | ||
| Wide field slitless spectroscopy | 2.4–5.0 | 2 × 129" × 129" | 0.063 | R ~ 1,600 at 4 µm |
| Time-series imaging | 0.6–2.3 2.4–5.0 | 129" × 129" | 0.031 0.063 | |
| Grism time series | 0.6–2.3 2.4–5.0 | 129" × 129" | 0.031 0.063 | R ~ 300 |
§ Smaller fields of view are available using subarrays in the imaging, time series imaging, and grism time-series modes.