NIRCam Observing Modes
JWST Near Infrared Camera (NIRCam) has 5 science observing modes: imaging, coronagraphy, grism wide field slitless spectroscopy, time-series imaging, and grism time series.
NIRCam's 5 observing modes have corresponding templates in the Astronomer's Proposal Tool (APT):
- Imaging using 10 detectors of two 2.2' × 2.2' fields separated by 44" covering 9.7 arcmin² in total, or using subsets of the detectors and/or subarrays for bright targets
- 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 provided in the short wavelength channel (0.6–2.3 µm) and long wavelength channel (2.4–5.0 µm) in all observing modes.
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, or imaging |
§ Smaller fields of view are available using subarrays in the imaging, time series imaging, and grism time-series modes. Conversely, the coronagraphic FOV here assumes subarrays are used, but full-frame observation are also supported.